Log D versus HPLC derived hydrophobicity: The development of predictive tools to aid in the rational design of bioactive peptoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bolt, H. L.; Williams, C. E. J.; Brooks, R. V.

Hydrophobicity has proven to be an extremely useful parameter in small molecule drug discovery programmes given that it can be used as a predictive tool to enable rational design. For larger molecules, including peptoids, where folding is possible, the situation is more complicated and the average hydrophobicity (as determined by RP-HPLC retention time) may not always provide an effective predictive tool for rational design. Herein, we report the first ever application of partitioning experiments to determine the log D values for a series of peptoids. By comparing log D and average hydrophobicities we highlight the potential advantage of employing themore » former as a predictive tool in the rational design of biologically active peptoids.« less

Surface-Directed Assembly of Sequence-Defined Synthetic Polymers into Networks of Hexagonally Patterned Nanoribbons with Controlled Functionalities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chun-Long; Zuckermann, Ronald N.; DeYoreo, James J.

The exquisite self-assembly of proteins and peptides in nature into highly ordered functional materials has inspired innovative approaches to biomimetic materials design and synthesis. Here we report the assembly of peptoids—a class of highly stable sequence-defined synthetic polymers—into biomimetic materials on mica surfaces. The assembling 12-mer peptoid contains alternating acidic and aromatic residues, and the presence of Ca2+ cations creates peptoid-peptoid and peptoid-mica interactions that drive assembly. In situ atomic force microscopy (AFM) shows that peptoids first assemble into discrete nanoparticles, these particles then transform into hexagonally-patterned nanoribbons on mica surfaces. AFM-based dynamic force spectroscopy (DFS) studies show that peptoid-micamore » interactions are much stronger than peptoidpeptoid interactions in the presence of Ca2+, illuminating the physical parameters that drive peptoid assembly. We further demonstrate the display of functional groups at the N-terminus of assembling peptoid sequence to produce biomimetic materials with similar hierarchical structures. This research demonstrates that surface-directed peptoid assembly can be used as a robust platform to develop biomimetic coating materials for applications.« less

Peptoid-Substituted Hybrid Antimicrobial Peptide Derived from Papiliocin and Magainin 2 with Enhanced Bacterial Selectivity and Anti-inflammatory Activity.

PubMed

Shin, Areum; Lee, Eunjung; Jeon, Dasom; Park, Young-Guen; Bang, Jeong Kyu; Park, Yong-Sun; Shin, Song Yub; Kim, Yangmee

2015-06-30

Antimicrobial peptides (AMPs) are important components of the host innate immune system. Papiliocin is a 37-residue AMP purified from larvae of the swallowtail butterfly Papilio xuthus. Magainin 2 is a 23-residue AMP purified from the skin of the African clawed frog Xenopus laevis. We designed an 18-residue hybrid peptide (PapMA) incorporating N-terminal residues 1-8 of papiliocin and N-terminal residues 4-12 of magainin 2, joined by a proline (Pro) hinge. PapMA showed high antimicrobial activity but was cytotoxic to mammalian cells. To decrease PapMA cytotoxicity, we designed a lysine (Lys) peptoid analogue, PapMA-k, which retained high antimicrobial activity but displayed cytotoxicity lower than that of PapMA. Fluorescent dye leakage experiments and confocal microscopy showed that PapMA targeted bacterial cell membranes whereas PapMA-k penetrated bacterial cell membranes. Nuclear magnetic resonance experiments revealed that PapMA contained an N-terminal α-helix from Lys(3) to Lys(7) and a C-terminal α-helix from Lys(10) to Lys(17), with a Pro(9) hinge between them. PapMA-k also had two α-helical structures in the same region connected with a flexible hinge residue at Nlys(9), which existed in a dynamic equilibrium of cis and trans conformers. Using lipopolysaccharide-stimulated RAW264.7 macrophages, the anti-inflammatory activity of PapMA and PapMA-k was confirmed by inhibition of nitric oxide and inflammatory cytokine production. In addition, treatment with PapMA and PapMA-k decreased the level of ultraviolet irradiation-induced expression of genes encoding matrix metalloproteinase-1 (MMP-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in human keratinocyte HaCaT cells. Thus, PapMA and PapMA-k are potent peptide antibiotics with antimicrobial and anti-inflammatory activity, with PapMA-k displaying enhanced bacterial selectivity.

In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents.

PubMed

Czyzewski, Ann M; Jenssen, Håvard; Fjell, Christopher D; Waldbrook, Matt; Chongsiriwatana, Nathaniel P; Yuen, Eddie; Hancock, Robert E W; Barron, Annelise E

2016-01-01

Bacterial resistance to conventional antibiotics is a global threat that has spurred the development of antimicrobial peptides (AMPs) and their mimetics as novel anti-infective agents. While the bioavailability of AMPs is often reduced due to protease activity, the non-natural structure of AMP mimetics renders them robust to proteolytic degradation, thus offering a distinct advantage for their clinical application. We explore the therapeutic potential of N-substituted glycines, or peptoids, as AMP mimics using a multi-faceted approach that includes in silico, in vitro, and in vivo techniques. We report a new QSAR model that we developed based on 27 diverse peptoid sequences, which accurately correlates antimicrobial peptoid structure with antimicrobial activity. We have identified a number of peptoids that have potent, broad-spectrum in vitro activity against multi-drug resistant bacterial strains. Lastly, using a murine model of invasive S. aureus infection, we demonstrate that one of the best candidate peptoids at 4 mg/kg significantly reduces with a two-log order the bacterial counts compared with saline-treated controls. Taken together, our results demonstrate the promising therapeutic potential of peptoids as antimicrobial agents.

Cyclization improves membrane permeation by antimicrobial peptoids

DOE PAGES

Andreev, Konstantin; Martynowycz, Michael W.; Ivankin, Andrey; ...

2016-10-28

The peptidomimetic approach has emerged as a powerful tool for overcoming the inherent limitations of natural antimicrobial peptides, where the therapeutic potential can be improved by increasing the selectivity and bioavailability. Restraining the conformational flexibility of a molecule may reduce the entropy loss upon its binding to the membrane. Experimental findings demonstrate that the cyclization of linear antimicrobial peptoids increases their bactericidal activity against Staphylococcus aureus while maintaining high hemolytic concentrations. Surface X-ray scattering shows that macrocyclic peptoids intercalate into Langmuir monolayers of anionic lipids with greater efficacy than for their linear analogues. Lastly, it is suggested that cyclization maymore » increase peptoid activity by allowing the macrocycle to better penetrate the bacterial cell membrane.« less

Cyclization improves membrane permeation by antimicrobial peptoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, Konstantin; Martynowycz, Michael W.; Ivankin, Andrey

The peptidomimetic approach has emerged as a powerful tool for overcoming the inherent limitations of natural antimicrobial peptides, where the therapeutic potential can be improved by increasing the selectivity and bioavailability. Restraining the conformational flexibility of a molecule may reduce the entropy loss upon its binding to the membrane. Experimental findings demonstrate that the cyclization of linear antimicrobial peptoids increases their bactericidal activity against Staphylococcus aureus while maintaining high hemolytic concentrations. Surface X-ray scattering shows that macrocyclic peptoids intercalate into Langmuir monolayers of anionic lipids with greater efficacy than for their linear analogues. Lastly, it is suggested that cyclization maymore » increase peptoid activity by allowing the macrocycle to better penetrate the bacterial cell membrane.« less

Identification of the minimum pharmacophore of lipid-phosphatidylserine (PS) binding peptide-peptoid hybrid PPS1D1.

PubMed

Singh, Jaspal; Shukla, Satya Prakash; Desai, Tanvi J; Udugamasooriya, D Gomika

2016-09-15

We previously reported a unique peptide-peptoid hybrid, PPS1 that specifically recognizes lipid-phosphatidylserine (PS) and a few other negatively charged phospholipids, but not neutral phospholipids, on the cell membrane. The dimeric version of PPS1, i.e., PPS1D1 triggers strong cancer cell cytotoxicity and has been validated in lung cancer models both in vitro and in vivo. Given that PS and other negatively charged phospholipids are abundant in almost all tumor microenvironments, PPS1D1 is an attractive drug lead that can be developed into a globally applicable anti-cancer agent. Therefore, it is extremely important to identify the minimum pharmacophore of PPS1D1. In this study, we have synthesized alanine/sarcosine derivatives as well as truncated derivatives of PPS1D1. We performed ELISA-like competitive binding assay to evaluate the PS-recognition potential and standard MTS cell viability assay on HCC4017 lung cancer cells to validate the cell cytotoxicity effects of these derivatives. Our studies indicate that positively charged residues at the second and third positions, as well as four hydrophobic residues at the fifth through eighth positions, are imperative for the binding and activity of PPS1D1. Methionine at the first position was not essential, whereas the positively charged Nlys at the fourth position was minimally needed, as two derivatives that were synthesized replacing this residue were almost as active as PPS1D1. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fragmentation Patterns and Mechanisms of Singly and Doubly Protonated Peptoids Studied by Collision Induced Dissociation

NASA Astrophysics Data System (ADS)

Ren, Jianhua; Tian, Yuan; Hossain, Ekram; Connolly, Michael D.

2016-04-01

Peptoids are peptide-mimicking oligomers consisting of N-alkylated glycine units. The fragmentation patterns for six singly and doubly protonated model peptoids were studied via collision-induced dissociation tandem mass spectrometry. The experiments were carried out on a triple quadrupole mass spectrometer with an electrospray ionization source. Both singly and doubly protonated peptoids were found to fragment mainly at the backbone amide bonds to produce peptoid B-type N-terminal fragment ions and Y-type C-terminal fragment ions. However, the relative abundances of B- versus Y-ions were significantly different. The singly protonated peptoids fragmented by producing highly abundant Y-ions and lesser abundant B-ions. The Y-ion formation mechanism was studied through calculating the energetics of truncated peptoid fragment ions using density functional theory and by controlled experiments. The results indicated that Y-ions were likely formed by transferring a proton from the C-H bond of the N-terminal fragments to the secondary amine of the C-terminal fragments. This proton transfer is energetically favored, and is in accord with the observation of abundant Y-ions. The calculations also indicated that doubly protonated peptoids would fragment at an amide bond close to the N-terminus to yield a high abundance of low-mass B-ions and high-mass Y-ions. The results of this study provide further understanding of the mechanisms of peptoid fragmentation and, therefore, are a valuable guide for de novo sequencing of peptoid libraries synthesized via combinatorial chemistry.

In Vivo, In Vitro, and In Silico Characterization of Peptoids as Antimicrobial Agents

PubMed Central

Fjell, Christopher D.; Waldbrook, Matt; Chongsiriwatana, Nathaniel P.; Yuen, Eddie; Hancock, Robert E. W.; Barron, Annelise E.

2016-01-01

Bacterial resistance to conventional antibiotics is a global threat that has spurred the development of antimicrobial peptides (AMPs) and their mimetics as novel anti-infective agents. While the bioavailability of AMPs is often reduced due to protease activity, the non-natural structure of AMP mimetics renders them robust to proteolytic degradation, thus offering a distinct advantage for their clinical application. We explore the therapeutic potential of N-substituted glycines, or peptoids, as AMP mimics using a multi-faceted approach that includes in silico, in vitro, and in vivo techniques. We report a new QSAR model that we developed based on 27 diverse peptoid sequences, which accurately correlates antimicrobial peptoid structure with antimicrobial activity. We have identified a number of peptoids that have potent, broad-spectrum in vitro activity against multi-drug resistant bacterial strains. Lastly, using a murine model of invasive S. aureus infection, we demonstrate that one of the best candidate peptoids at 4 mg/kg significantly reduces with a two-log order the bacterial counts compared with saline-treated controls. Taken together, our results demonstrate the promising therapeutic potential of peptoids as antimicrobial agents. PMID:26849681

Pyrimidinone-Peptoid Hybrid Molecules with Distinct Effects on Molecular Chaperone Function and Cell Proliferation

PubMed Central

Wright, Christine M.; Chovatiya, Raj J.; Jameson, Nora E.; Turner, David M.; Zhu, Guangyu; Werner, Stefan; Huryn, Donna M.; Pipas, James M.; Day, Billy W.; Wipf, Peter; Brodsky, Jeffrey L.

2008-01-01

The Hsp70 molecular chaperones are ATPases that play critical roles in the pathogenesis of many human diseases, including breast cancer. Hsp70 ATP hydrolysis is relatively weak, but is stimulated by J domain-containing proteins. We identified pyrimidinone-peptoid hybrid molecules that inhibit cell proliferation with greater potency than previously described Hsp70 modulators. In many cases, anti-proliferative activity correlated with inhibition of J domain stimulation of Hsp70. PMID:18164205

Targeting PCNA Phosphorylation in Breast Cancer

DTIC Science & Technology

2012-04-01

inhibitor and dyes. These basic peptides and polycationic peptoids were labeled with fluorescein and used to assess the effect of structure on cellular... substitution of a peptoid conjugate that was synthesized during the project period. Additional types of analogs were prepared as well each providing...Broceta, A., Diezmann, F., Ou-Yang, C. Y., Fara, M. A. & Bradley, M. Synthesis, penetrability and intracellular targeting of fluorescein -tagged

Investigating rhodamine B-labeled peptoids: scopes and limitations of its applications.

PubMed

Birtalan, Esther; Rudat, Birgit; Kölmel, Dominik K; Fritz, Daniel; Vollrath, Sidonie B L; Schepers, Ute; Bräse, Stefan

2011-01-01

The fluorophore rhodamine B is often used in biological assays. It is inexpensive, robust under a variety of reaction conditions, can be covalently linked to bioactive molecules, and has suitable spectral properties in terms of absorption and fluorescence wavelength. Nonetheless, there are some drawbacks: it can readily form a spirolactam compound, which is nonfluorescent, and therefore may not be the dye of choice for all fluorescence microscopy applications. Herein this spirolactam formation was observed by purifying such a labeled peptoid with high performance liquid chromatography (HPLC) and monitored in detail by making a series of analytical HPLC runs over time. Additionally, a small library of eight peptoids with rhodamine B as label was synthesized. Analysis of the absorption properties of these molecules demonstrated that the problem of fluorescence loss can be overcome by coupling secondary amines with rhodamine B.

Role of monomer sequence and backbone chemistry in polypeptoid copolymers for marine antifouling coatings

NASA Astrophysics Data System (ADS)

Patterson, Anastasia; Wenning, Brandon; Rizis, Georgios; Calabrese, David; Finlay, John; Franco, Sofia; Clare, Anthony; Kramer, Edward; Ober, Christopher; Segalman, Rachel

The design rules elucidated in this work suggest that antifouling coatings bearing pendant peptoid side chains perform better overall in marine fouling tests than those with peptide side chains, with extremely low attachment of N. incerta and high removal of U. linza. This difference in performance is likely due to the lack of a hydrogen bond donor in the peptoid backbone. Furthermore, we show that the bulk polymer material of these hierarchical coatings (based on PEO or PDMS) plays a key role in determining both surface presentation and fouling release performance. We demonstrate these trends utilizing a modular coating based on a triblock copolymer consisting of polystyrene and a vinyl-containing midblock, to which sequence-defined pendant oligomers (peptides or peptoids with sequences of oligo-PEO and fluoroalkyl groups) are attached via thiol-ene ``click'' chemistry. Surface presentation was analyzed with X-ray photoelectron spectroscopy and captive bubble water contact angle, and antifouling performance was evaluated with attachment and removal bioassays of the marine macroalga U. linza and diatom N. incerta. NSF GRFP and ONR PECASE.

Triangular prism-shaped β-peptoid helices as unique biomimetic scaffolds

NASA Astrophysics Data System (ADS)

Laursen, Jonas S.; Harris, Pernille; Fristrup, Peter; Olsen, Christian A.

2015-05-01

β-Peptoids are peptidomimetics based on N-alkylated β-aminopropionic acid residues (or N-alkyl-β-alanines). This type of peptide mimic has previously been incorporated in biologically active ligands and has been hypothesized to be able to exhibit foldamer properties. Here we show, for the first time, that β-peptoids can be tuned to fold into stable helical structures. We provide high-resolution X-ray crystal structures of homomeric β-peptoid hexamers, which reveal right-handed helical conformations with exactly three residues per turn and a helical pitch of 9.6-9.8 Å between turns. The presence of folded conformations in solution is supported by circular dichroism spectroscopy showing length- and solvent dependency, and molecular dynamics simulations provide further support for a stabilized helical secondary structure in organic solvent. We thus outline a framework for future design of novel biomimetics that display functional groups with high accuracy in three dimensions, which has potential for development of new functional materials.

Solid-phase submonomer synthesis of peptoid polymers and their self-assembly into highly-ordered nanosheets.

PubMed

Tran, Helen; Gael, Sarah L; Connolly, Michael D; Zuckermann, Ronald N

2011-11-02

Peptoids are a novel class of biomimetic, non-natural, sequence-specific heteropolymers that resist proteolysis, exhibit potent biological activity, and fold into higher order nanostructures. Structurally similar to peptides, peptoids are poly N-substituted glycines, where the side chains are attached to the nitrogen rather than the alpha-carbon. Their ease of synthesis and structural diversity allows testing of basic design principles to drive de novo design and engineering of new biologically-active and nanostructured materials. Here, a simple manual peptoid synthesis protocol is presented that allows the synthesis of long chain polypeptoids (up to 50mers) in excellent yields. Only basic equipment, simple techniques (e.g. liquid transfer, filtration), and commercially available reagents are required, making peptoids an accessible addition to many researchers' toolkits. The peptoid backbone is grown one monomer at a time via the submonomer method which consists of a two-step monomer addition cycle: acylation and displacement. First, bromoacetic acid activated in situ with N,N'-diisopropylcarbodiimide acylates a resin-bound secondary amine. Second, nucleophilic displacement of the bromide by a primary amine follows to introduce the side chain. The two-step cycle is iterated until the desired chain length is reached. The coupling efficiency of this two-step cycle routinely exceeds 98% and enables the synthesis of peptoids as long as 50 residues. Highly tunable, precise and chemically diverse sequences are achievable with the submonomer method as hundreds of readily available primary amines can be directly incorporated. Peptoids are emerging as a versatile biomimetic material for nanobioscience research because of their synthetic flexibility, robustness, and ordering at the atomic level. The folding of a single-chain, amphiphilic, information-rich polypeptoid into a highly-ordered nanosheet was recently demonstrated. This peptoid is a 36-mer that consists of only three different commercially available monomers: hydrophobic, cationic and anionic. The hydrophobic phenylethyl side chains are buried in the nanosheet core whereas the ionic amine and carboxyl side chains align on the hydrophilic faces. The peptoid nanosheets serve as a potential platform for membrane mimetics, protein mimetics, device fabrication, and sensors. Methods for peptoid synthesis, sheet formation, and microscopy imaging are described and provide a simple method to enable future peptoid nanosheet designs.

Divalent Ion Parameterization Strongly Affects Conformation and Interactions of an Anionic Biomimetic Polymer.

PubMed

Daily, Michael D; Baer, Marcel D; Mundy, Christopher J

2016-03-10

The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids using a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical force field (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through side chain-side chain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described.

Guanidino Groups Greatly Enhance the Action of Antimicrobial Peptidomimetics Against Bacterial Cytoplasmic Membranes

DTIC Science & Technology

2014-05-28

SECURITY CLASSIFICATION OF: Antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the...effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial ?- peptide ...P.O. Box 12211 Research Triangle Park, NC 27709-2211 Antimicrobial peptidomimetics; Peptide –peptoid chimeras; Guanidinium cation; Bacterial

Cryptic bioactivity capacitated by synthetic hybrid plant peptides

PubMed Central

Hirakawa, Yuki; Shinohara, Hidefumi; Welke, Kai; Irle, Stephan; Matsubayashi, Yoshikatsu; Torii, Keiko U.; Uchida, Naoyuki

2017-01-01

Evolution often diversifies a peptide hormone family into multiple subfamilies, which exert distinct activities by exclusive interaction with specific receptors. Here we show that systematic swapping of pre-existing variation in a subfamily of plant CLE peptide hormones leads to a synthetic bifunctional peptide that exerts activities beyond the original subfamily by interacting with multiple receptors. This approach provides new insights into the complexity and specificity of peptide signalling. PMID:28165456

Effects of hydrophobic helix length and side chain chemistry on biomimicry in peptoid analogues of SP-C.

PubMed

Brown, Nathan J; Wu, Cindy W; Seurynck-Servoss, Shannon L; Barron, Annelise E

2008-02-12

The hydrophobic proteins of lung surfactant (LS), SP-B and SP-C, are critical constituents of an effective surfactant replacement therapy for the treatment of respiratory distress syndrome. Because of concerns and difficulties associated with animal-derived surfactants, recent investigations have focused on the creation of synthetic analogues of the LS proteins. However, creating an accurate mimic of SP-C that retains its biophysical surface activity is extraordinarily challenging given the lipopeptide's extreme hydrophobicity and propensity to misfold and aggregate. One successful approach that overcomes these difficulties is the use of poly-N-substituted glycines, or peptoids, to mimic SP-C. To develop a non-natural, bioactive mimic of SP-C and to investigate the effects of side chain chemistry and length of the helical hydrophobic region, we synthesized, purified, and performed in vitro testing of two classes of peptoid SP-C mimics: those having a rigid alpha-chiral aromatic helix and those having a biomimetic alpha-chiral aliphatic helix. The length of the two classes of mimics was also systematically altered. Circular dichroism spectroscopy gave evidence that all of the peptoid-based mimics studied here emulated SP-C's secondary structure, forming stable helical structures in solution. Langmuir-Wilhelmy surface balance, fluorescence microscopy, and pulsating bubble surfactometry experiments provide evidence that the aromatic-based SP-C peptoid mimics, in conjunction with a synthetic lipid mixture, have superior surface activity and biomimetic film morphology in comparison to the aliphatic-based mimics and that there is an increase in surface activity corresponding to increasing helical length.

Directed Evolution of a Cyclized Peptoid-Peptide Chimera against a Cell-Free Expressed Protein and Proteomic Profiling of the Interacting Proteins to Create a Protein-Protein Interaction Inhibitor.

PubMed

Kawakami, Takashi; Ogawa, Koji; Hatta, Tomohisa; Goshima, Naoki; Natsume, Tohru

2016-06-17

N-alkyl amino acids are useful building blocks for the in vitro display evolution of ribosomally synthesized peptides because they can increase the proteolytic stability and cell permeability of these peptides. However, the translation initiation substrate specificity of nonproteinogenic N-alkyl amino acids has not been investigated. In this study, we screened various N-alkyl amino acids and nonamino carboxylic acids for translation initiation with an Escherichia coli reconstituted cell-free translation system (PURE system) and identified those that efficiently initiated translation. Using seven of these efficiently initiating acids, we next performed in vitro display evolution of cyclized peptidomimetics against an arbitrarily chosen model human protein (β-catenin) cell-free expressed from its cloned cDNA (HUPEX) and identified a novel β-catenin-binding cyclized peptoid-peptide chimera. Furthermore, by a proteomic approach using direct nanoflow liquid chromatography-tandem mass spectrometry (DNLC-MS/MS), we successfully identified which protein-β-catenin interaction is inhibited by the chimera. The combination of in vitro display evolution of cyclized N-alkyl peptidomimetics and in vitro expression of human proteins would be a powerful approach for the high-speed discovery of diverse human protein-targeted cyclized N-alkyl peptidomimetics.

Peptide-laden mesoporous silica nanoparticles with promoted bioactivity and osteo-differentiation ability for bone tissue engineering.

PubMed

Luo, Zuyuan; Deng, Yi; Zhang, Ranran; Wang, Mengke; Bai, Yanjie; Zhao, Qiang; Lyu, Yalin; Wei, Jie; Wei, Shicheng

2015-07-01

Combination of mesoporous silica materials and bioactive factors is a promising niche-mimetic solution as a hybrid bone substitution for bone tissue engineering. In this work, we have synthesized biocompatible silica-based nanoparticles with abundant mesoporous structure, and incorporated bone-forming peptide (BFP) derived from bone morphogenetic protein-7 (BMP-7) into the mesoporous silica nanoparticles (MSNs) to obtain a slow-release system for osteogenic factor delivery. The chemical characterization demonstrates that the small osteogenic peptide is encapsulated in the mesoporous successfully, and the nitrogen adsorption-desorption isotherms suggest that the peptide encapsulation has no influence on mesoporous structure of MSNs. In the cell experiment, the peptide-laden MSNs (p-MSNs) show higher MG-63 cell proliferation, spreading and alkaline phosphatase (ALP) activity than the bare MSNs, indicating good in vitro cytocompatibility. Simultaneously, the osteogenesis-related proteins expression and calcium mineral deposition disclose enhanced osteo-differentiation of human mesenchymal stem cells (hMSCs) under the stimulation of the p-MSNs, confirming that BFP released from MSNs could significantly promote the osteogenic differentiation of hMSCs, especially at 500μg/mL of p-MSNs concentration. The peptide-modified MSNs with better bioactivity and osteogenic differentiation make it a potential candidate as bioactive material for bone repairing, bone regeneration, and bio-implant coating applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Solid-Phase Synthesis of Diverse Peptide Tertiary Amides By Reductive Amination

PubMed Central

Pels, Kevin; Kodadek, Thomas

2015-01-01

The synthesis of libraries of conformationally-constrained peptide-like oligomers is an important goal in combinatorial chemistry. In this regard an attractive building block is the N-alkylated peptide, also known as peptide tertiary amide (PTA). PTAs are strongly biased conformationally due to allylic 1,3 strain interactions. We report here an improved synthesis of these species on solid supports through the use of reductive amination chemistry using amino acid-terminated, bead-displayed oligomers and diverse aldehydes. The utility of this chemistry is demonstrated by the synthesis of a library of 10,000 mixed peptoid-PTA oligomers. PMID:25695359

Solid-phase synthesis of diverse peptide tertiary amides by reductive amination.

PubMed

Pels, Kevin; Kodadek, Thomas

2015-03-09

The synthesis of libraries of conformationally constrained peptide-like oligomers is an important goal in combinatorial chemistry. In this regard an attractive building block is the N-alkylated peptide, also known as a peptide tertiary amide (PTA). PTAs are conformationally constrained because of allylic 1,3 strain interactions. We report here an improved synthesis of these species on solid supports through the use of reductive amination chemistry using amino acid-terminated, bead-displayed oligomers and diverse aldehydes. The utility of this chemistry is demonstrated by the synthesis of a library of 10,000 mixed peptoid-PTA oligomers.

Transition metal ions mediated tyrosine based short peptide amphiphile nanostructures inhibit bacterial growth.

PubMed

Joshi, Khashti Ballabh; Singh, Ramesh; Mishra, Narendra Kumar; Kumar, Vikas; Vinayak, Vandana

2018-05-17

We report the design and synthesis of biocompatible small peptide based molecule for the controlled and targeted delivery of the encapsulated bioactive metal ions via transforming their internal nanostructures. Tyrosine based short peptide amphiphile (sPA) was synthesized which self-assembled into β-sheet like secondary structures. The self assembly of the designed sPA was modulated by using different bioactive transition metal ions which is confirmed by spectroscopic and microscopic techniques. These bioactive metal ions conjugated sPA hybrid structures are further used to develop antibacterial materials. It is due to the excellent antibacterial activity of zinc ions that the growth of clinically relevant bacteria such as E. Coli was inhibited in the presence of zinc-sPA conjugate. The bacterial test demonstrated that owing to high biocompatibility with bacterial cell, the designed sPA worked as metal ions delivery agent and therefore it can show great potential in locally addressing bacterial infections. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Collagenolytic Matrix Metalloproteinase Activities toward Peptomeric Triple-Helical Substrates.

PubMed

Stawikowski, Maciej J; Stawikowska, Roma; Fields, Gregg B

2015-05-19

Although collagenolytic matrix metalloproteinases (MMPs) possess common domain organizations, there are subtle differences in their processing of collagenous triple-helical substrates. In this study, we have incorporated peptoid residues into collagen model triple-helical peptides and examined MMP activities toward these peptomeric chimeras. Several different peptoid residues were incorporated into triple-helical substrates at subsites P3, P1, P1', and P10' individually or in combination, and the effects of the peptoid residues were evaluated on the activities of full-length MMP-1, MMP-8, MMP-13, and MMP-14/MT1-MMP. Most peptomers showed little discrimination between MMPs. However, a peptomer containing N-methyl Gly (sarcosine) in the P1' subsite and N-isobutyl Gly (NLeu) in the P10' subsite was hydrolyzed efficiently only by MMP-13 [nomenclature relative to the α1(I)772-786 sequence]. Cleavage site analysis showed hydrolysis at the Gly-Gln bond, indicating a shifted binding of the triple helix compared to the parent sequence. Favorable hydrolysis by MMP-13 was not due to sequence specificity or instability of the substrate triple helix but rather was based on the specific interactions of the P7' peptoid residue with the MMP-13 hemopexin-like domain. A fluorescence resonance energy transfer triple-helical peptomer was constructed and found to be readily processed by MMP-13, not cleaved by MMP-1 and MMP-8, and weakly hydrolyzed by MT1-MMP. The influence of the triple-helical structure containing peptoid residues on the interaction between MMP subsites and individual substrate residues may provide additional information about the mechanism of collagenolysis, the understanding of collagen specificity, and the design of selective MMP probes.

Selectivity in the potentiation of antibacterial activity of α-peptide/β-peptoid peptidomimetics and antimicrobial peptides by human blood plasma.

PubMed

Hein-Kristensen, Line; Knapp, Kolja M; Franzyk, Henrik; Gram, Lone

2013-11-01

Antimicrobial peptides (AMPs) are promising leads for novel antibiotics; however, their activity is often compromised under physiological conditions. The purpose of this study was to determine the activity of α-peptide/β-peptoid peptidomimetics and AMPs against Escherichia coli and Staphylococcus aureus in the presence of human blood-derived matrices and immune effectors. The minimum inhibitory concentration (MIC) of two peptidomimetics against E. coli decreased by up to one order of magnitude when determined in 50% blood plasma as compared to MHB media. The MIC of a membrane-active AMP, LL-I/3, also decreased, whereas two intracellularly acting AMPs were not potentiated by plasma. Blood serum had no effect on activity against E. coli and neither matrix had an effect on activity against S. aureus. Unexpectedly, physiological concentrations of human serum albumin did not influence activity. Plasma potentiation was not mediated by an LL-37 analogue, lysozyme or hydrogen peroxide; however, plasma potentiation of activity was abolished when the complement system was heat-inactivated. Time-course experiments indicated that potentiation was due to plasma-mediated effects on bacterial cells prior to activities of peptidomimetics. The unexpected enhancement of antibacterial activity of peptidomimetics and AMPs under physiological conditions significantly increases the therapeutic potential of these compounds. Copyright © 2013 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Mass Spectrometry and Ion Mobility Characterization of Bioactive Peptide-Synthetic Polymer Conjugates.

PubMed

Alalwiat, Ahlam; Tang, Wen; Gerişlioğlu, Selim; Becker, Matthew L; Wesdemiotis, Chrys

2017-01-17

The bioconjugate BMP2-(PEO-HA) 2 , composed of a dendron with two monodisperse poly(ethylene oxide) (PEO) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone growth stimulating peptide (BMP2), has been comprehensively characterized by mass spectrometry (MS) methods, encompassing matrix-assisted laser desorption ionization (MALDI), electrospray ionization (ESI), tandem mass spectrometry (MS 2 ), and ion mobility mass spectrometry (IM-MS). MS 2 experiments using different ion activation techniques validated the sequences of the synthetic, bioactive peptides HA and BMP2, which contained highly basic amino acid residues either at the N-terminus (BMP2) or C-terminus (HA). Application of MALDI-MS, ESI-MS, and IM-MS to the polymer-peptide biomaterial confirmed its composition. Collision cross-section measurements and molecular modeling indicated that BMP2-(PEO-HA) 2 exists in several folded and extended conformations, depending on the degree of protonation. Protonation of all basic sites of the hybrid material nearly doubles its conformational space and accessible surface area.

Peptides, polypeptides and peptide-polymer hybrids as nucleic acid carriers.

PubMed

Ahmed, Marya

2017-10-24

Cell penetrating peptides (CPPs), and protein transduction domains (PTDs) of viruses and other natural proteins serve as a template for the development of efficient peptide based gene delivery vectors. PTDs are sequences of acidic or basic amphipathic amino acids, with superior membrane trespassing efficacies. Gene delivery vectors derived from these natural, cationic and cationic amphipathic peptides, however, offer little flexibility in tailoring the physicochemical properties of single chain peptide based systems. Owing to significant advances in the field of peptide chemistry, synthetic mimics of natural peptides are often prepared and have been evaluated for their gene expression, as a function of amino acid functionalities, architecture and net cationic content of peptide chains. Moreover, chimeric single polypeptide chains are prepared by a combination of multiple small natural or synthetic peptides, which imparts distinct physiological properties to peptide based gene delivery therapeutics. In order to obtain multivalency and improve the gene delivery efficacies of low molecular weight cationic peptides, bioactive peptides are often incorporated into a polymeric architecture to obtain novel 'polymer-peptide hybrids' with improved gene delivery efficacies. Peptide modified polymers prepared by physical or chemical modifications exhibit enhanced endosomal escape, stimuli responsive degradation and targeting efficacies, as a function of physicochemical and biological activities of peptides attached onto a polymeric scaffold. The focus of this review is to provide comprehensive and step-wise progress in major natural and synthetic peptides, chimeric polypeptides, and peptide-polymer hybrids for nucleic acid delivery applications.

Physics and chemistry-driven artificial neural network for predicting bioactivity of peptides and proteins and their design.

PubMed

Huang, Ri-Bo; Du, Qi-Shi; Wei, Yu-Tuo; Pang, Zong-Wen; Wei, Hang; Chou, Kuo-Chen

2009-02-07

Predicting the bioactivity of peptides and proteins is an important challenge in drug development and protein engineering. In this study we introduce a novel approach, the so-called "physics and chemistry-driven artificial neural network (Phys-Chem ANN)", to deal with such a problem. Unlike the existing ANN approaches, which were designed under the inspiration of biological neural system, the Phys-Chem ANN approach is based on the physical and chemical principles, as well as the structural features of proteins. In the Phys-Chem ANN model the "hidden layers" are no longer virtual "neurons", but real structural units of proteins and peptides. It is a hybridization approach, which combines the linear free energy concept of quantitative structure-activity relationship (QSAR) with the advanced mathematical technique of ANN. The Phys-Chem ANN approach has adopted an iterative and feedback procedure, incorporating both machine-learning and artificial intelligence capabilities. In addition to making more accurate predictions for the bioactivities of proteins and peptides than is possible with the traditional QSAR approach, the Phys-Chem ANN approach can also provide more insights about the relationship between bioactivities and the structures involved than the ANN approach does. As an example of the application of the Phys-Chem ANN approach, a predictive model for the conformational stability of human lysozyme is presented.

Monosaccharides as Scaffolds for the Synthesis of Novel Compounds

NASA Astrophysics Data System (ADS)

Murphy, Paul V.; Velasco-Torrijos, Trinidad

This chapter focuses on monosaccharides and scaffolds their derivatives as scaffolds for the synthesis of primarily bioactive compounds. Such carbohydrate derivatives have been designed to modulate mainly protein-protein and peptide-protein interactions although modulators of carbohydrate-protein and carbohydrate-nucleic acid interactions have also been of interest. The multiple hydroxyl groups that are present on saccharides have made pyranose, furanose and iminosugars ideal templates or scaffolds to which recognition or pharmacophoric groups can be grafted to generate novel compounds for medicinal chemistry. The synthesis of compounds for evaluations require strategies for regioselective reactions of saccharide hydroxyl groups and use of orthogonally stable protecting groups. Syntheses have been carried out on the solid phase and in solution. Also the use of uronic acids, amino sugars and sugar amino acids has facilitated the synthesis of peptidomimetics and prospecting libraries as they enable, through presence of amino or carboxylic acid groups, chemoselective approaches to be employed in solution and on solid phase. Sugar amino acids are readily incorporated, as peptide isosteres, to generate sugar-peptide hybrids or for the synthesis of novel carbopeptoids . The synthesis of new cyclic compounds, derived in part from saccharides, and their application as scaffolds is an emerging area and recent examples include spirocyclic compounds, benzodiazepine-saccharide hybrids and macrolide-saccharide hybrids. Potent bioactive saccharide derivatives have been identified that include enzyme inhibitors , somatostatin receptor ligands, integrin ligands, anti-viral compounds, shiga toxin inhibitors and cell growth inhibitors. Some saccharide derivatives have demonstrated improved cellular permeability when compared with peptides and are in clinical trials.

Divalent Ion Parameterization Strongly Affects Conformation and Interactions of an Anionic Biomimetic Polymer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daily, Michael D.; Baer, Marcel D.; Mundy, Christopher J.

2016-03-10

The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids usingmore » a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical forcefield (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through sidechain-sidechain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described. MDD was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. Research was funded by the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MDB acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Material & Engineering. CJM acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. PNNL is a multiprogram national laboratory operated by Battelle for the U.S. Department of Energy.« less

Hybrid bone implants: self-assembly of peptide amphiphile nanofibers within porous titanium.

PubMed

Sargeant, Timothy D; Guler, Mustafa O; Oppenheimer, Scott M; Mata, Alvaro; Satcher, Robert L; Dunand, David C; Stupp, Samuel I

2008-01-01

Over the past few decades there has been great interest in the use of orthopedic and dental implants that integrate into tissue by promoting bone ingrowth or bone adhesion, thereby eliminating the need for cement fixation. However, strategies to create bioactive implant surfaces to direct cellular activity and mineralization leading to osteointegration are lacking. We report here on a method to prepare a hybrid bone implant material consisting of a Ti-6Al-4V foam, whose 52% porosity is filled with a peptide amphiphile (PA) nanofiber matrix. These PA nanofibers can be highly bioactive by molecular design, and are used here as a strategy to transform an inert titanium foam into a potentially bioactive implant. Using scanning electron microscopy (SEM) and confocal microscopy, we show that PA molecules self-assemble into a nanofiber matrix within the pores of the metallic foam, fully occupying the foam's interconnected porosity. Furthermore, the method allows the encapsulation of cells within the bioactive matrix, and under appropriate conditions the nanofibers can nucleate mineralization of calcium phosphate phases with a Ca:P ratio that corresponds to that of hydroxyapatite. Cell encapsulation was quantified using a DNA measuring assay and qualitatively verified by SEM and confocal microscopy. An in vivo experiment was performed using a bone plug model in the diaphysis of the hind femurs of a Sprague Dawley rat and examined by histology to evaluate the performance of these hybrid systems after 4 weeks of implantation. Preliminary results demonstrate de novo bone formation around and inside the implant, vascularization around the implant, as well as the absence of a cytotoxic response. The PA-Ti hybrid strategy could be potentially tailored to initiate mineralization and direct a cellular response from the host tissue into porous implants to form new bone and thereby improve fixation, osteointegration, and long term stability of implants.

Highly efficient, nonpeptidic oligoguanidinium vectors that selectively internalize into mitochondria.

PubMed

Fernández-Carneado, Jimena; Van Gool, Michiel; Martos, Vera; Castel, Susanna; Prados, Pilar; de Mendoza, Javier; Giralt, Ernest

2005-01-26

Oligoguanidinium-based cell delivery systems have gained broad interest in the drug delivery field since one decade ago. Thus, arginine-containing peptides as Tat or Antp, oligoarginine peptides, and derived peptoids have been described as shuttles for delivering nonpermeant drugs inside cancer cells. Herein we report a new family of tetraguanidinium cell penetrating vectors efficiently internalized in human tumor cells. Their high internalization, studied by confocal microscopy and flow cytometry, as well as their specific accumulation in mitochondria makes these new vectors likely vehicles for the targeted delivery of anticancer drugs to mitochondria.

Bio-inspired synthesis of hybrid silica nanoparticles templated from elastin-like polypeptide micelles

NASA Astrophysics Data System (ADS)

Han, Wei; MacEwan, Sarah R.; Chilkoti, Ashutosh; López, Gabriel P.

2015-07-01

The programmed self-assembly of block copolymers into higher order nanoscale structures offers many attractive attributes for the development of new nanomaterials for numerous applications including drug delivery and biosensing. The incorporation of biomimetic silaffin peptides in these block copolymers enables the formation of hybrid organic-inorganic materials, which can potentially enhance the utility and stability of self-assembled nanostructures. We demonstrate the design, synthesis and characterization of amphiphilic elastin-like polypeptide (ELP) diblock copolymers that undergo temperature-triggered self-assembly into well-defined spherical micelles. Genetically encoded incorporation of the silaffin R5 peptide at the hydrophilic terminus of the diblock ELP leads to presentation of the silaffin R5 peptide on the coronae of the micelles, which results in localized condensation of silica and the formation of near-monodisperse, discrete, sub-100 nm diameter hybrid ELP-silica particles. This synthesis method, can be carried out under mild reaction conditions suitable for bioactive materials, and will serve as the basis for the development and application of functional nanomaterials. Beyond silicification, the general strategies described herein may also be adapted for the synthesis of other biohybrid nanomaterials as well.The programmed self-assembly of block copolymers into higher order nanoscale structures offers many attractive attributes for the development of new nanomaterials for numerous applications including drug delivery and biosensing. The incorporation of biomimetic silaffin peptides in these block copolymers enables the formation of hybrid organic-inorganic materials, which can potentially enhance the utility and stability of self-assembled nanostructures. We demonstrate the design, synthesis and characterization of amphiphilic elastin-like polypeptide (ELP) diblock copolymers that undergo temperature-triggered self-assembly into well-defined spherical micelles. Genetically encoded incorporation of the silaffin R5 peptide at the hydrophilic terminus of the diblock ELP leads to presentation of the silaffin R5 peptide on the coronae of the micelles, which results in localized condensation of silica and the formation of near-monodisperse, discrete, sub-100 nm diameter hybrid ELP-silica particles. This synthesis method, can be carried out under mild reaction conditions suitable for bioactive materials, and will serve as the basis for the development and application of functional nanomaterials. Beyond silicification, the general strategies described herein may also be adapted for the synthesis of other biohybrid nanomaterials as well. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr01407g

Incorporation of a Bio-Active Reverse-Turn Heterocycle into a Peptide Template Using Solid-Phase Synthesis to Probe Melanocortin Receptor Selectivity and Ligand Conformations by 2D 1H NMR

PubMed Central

Singh, Anamika; Wilczynski, Andrzej; Holder, Jerry R.; Witek, Rachel M.; Dirain, Marvin L.; Xiang, Zhimin; Edison, Arthur S.; Haskell-Luevano, Carrie

2011-01-01

Using a solid-phase synthetic approach, a bioactive reverse turn heterocyclic was incorporated into a cyclic peptide template to probe melanocortin receptor potency and ligand structural conformations. The five melanocortin receptor isoforms (MC1R-MC5R) are G-protein coupled receptors (GPCRs) that are regulated by endogenous agonists and antagonists. This pathway is involved in pigmentation, weight, and energy homeostasis. Herein, we report novel analogues of the chimeric AGRP-melanocortin peptide template integrated with a small molecule moiety to probe the structural and functional consequences of the core His-Phe-Arg-Trp peptide domain using a reverse-turn heterocycle. A series of six compounds are reported that result in inactive to full agonists with nM potency. Biophysical structural analysis [2D 1H NMR and computer-assisted molecular modeling (CAMM)] were performed on selected analogues, resulting in the identification that these peptide-small molecule hybrids possessed increased flexibility and fewer discrete conformational families as compared to the reference peptide and result in a novel template for further structure-function studies. PMID:21306168

Design-Based Peptidomimetic Ligand Discovery to Target HIV TAR RNA Using Comparative Analysis of Different Docking Methods.

PubMed

Fu, Junjie; Xia, Amy; Dai, Yao; Qi, Xin

2016-01-01

Discovering molecules capable of binding to HIV trans-activation responsive region (TAR) RNA thereby disrupting its interaction with Tat protein is an attractive strategy for developing novel antiviral drugs. Computational docking is considered as a useful tool for predicting binding affinity and conducting virtual screening. Although great progress in predicting protein-ligand interactions has been achieved in the past few decades, modeling RNA-ligand interactions is still largely unexplored due to the highly flexible nature of RNA. In this work, we performed molecular docking study with HIV TAR RNA using previously identified cyclic peptide L22 and its analogues with varying affinities toward HIV-1 TAR RNA. Furthermore, sarcosine scan was conducted to generate derivatives of CGP64222, a peptide-peptoid hybrid with inhibitory activity on Tat/TAR RNA interaction. Each compound was docked using CDOCKER, Surflex-Dock and FlexiDock to compare the effectiveness of each method. It was found that FlexiDock energy values correlated well with the experimental Kd values and could be used to predict the affinity of the ligands toward HIV-1 TAR RNA with a superior accuracy. Our results based on comparative analysis of different docking methods in RNA-ligand modeling will facilitate the structure-based discovery of HIV TAR RNA ligands for antiviral therapy.

StraPep: a structure database of bioactive peptides

PubMed Central

Wang, Jian; Yin, Tailang; Xiao, Xuwen; He, Dan; Xue, Zhidong; Jiang, Xinnong; Wang, Yan

2018-01-01

Abstract Bioactive peptides, with a variety of biological activities and wide distribution in nature, have attracted great research interest in biological and medical fields, especially in pharmaceutical industry. The structural information of bioactive peptide is important for the development of peptide-based drugs. Many databases have been developed cataloguing bioactive peptides. However, to our knowledge, database dedicated to collect all the bioactive peptides with known structure is not available yet. Thus, we developed StraPep, a structure database of bioactive peptides. StraPep holds 3791 bioactive peptide structures, which belong to 1312 unique bioactive peptide sequences. About 905 out of 1312 (68%) bioactive peptides in StraPep contain disulfide bonds, which is significantly higher than that (21%) of PDB. Interestingly, 150 out of 616 (24%) bioactive peptides with three or more disulfide bonds form a structural motif known as cystine knot, which confers considerable structural stability on proteins and is an attractive scaffold for drug design. Detailed information of each peptide, including the experimental structure, the location of disulfide bonds, secondary structure, classification, post-translational modification and so on, has been provided. A wide range of user-friendly tools, such as browsing, sequence and structure-based searching and so on, has been incorporated into StraPep. We hope that this database will be helpful for the research community. Database URL: http://isyslab.info/StraPep PMID:29688386

Bioactive peptides derived from traditional Chinese medicine and traditional Chinese food: A review.

PubMed

Liu, Ming; Wang, Yunpu; Liu, Yuhuan; Ruan, Roger

2016-11-01

There is an urgent treat of numerous chronic diseases including heart disease, stroke, cancer, chronic respiratory diseases and diabetes, which have a significant influence on the health of people worldwide. In addition to numerous preventive and therapeutic drug treatments, important advances have been achieved in the identification of bioactive peptides that may contribute to long-term health. Although bioactive peptides with various biological activities received unprecedented attention, as a new source of bioactive peptides, the significant role of bioactive peptides from traditional Chinese medicine and traditional Chinese food has not fully appreciated compared to other bioactive components. Hence, identification and bioactivity assessment of these peptides could benefit the pharmaceutical and food industry. Furthermore, the functional properties of bioactive peptides help to demystify drug properties and health benefits of traditional Chinese medicine and traditional Chinese food. This paper reviews the generation and biofunctional properties of various bioactive peptides derived from traditional Chinese medicine and traditional Chinese food. Mechanisms of digestion, bioavailability of bioactive peptides and interactions between traditional Chinese medicine and traditional Chinese food are also summarized in this review. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards the Improved Discovery and Design of Functional Peptides: Common Features of Diverse Classes Permit Generalized Prediction of Bioactivity

PubMed Central

Mooney, Catherine; Haslam, Niall J.; Pollastri, Gianluca; Shields, Denis C.

2012-01-01

The conventional wisdom is that certain classes of bioactive peptides have specific structural features that endow their particular functions. Accordingly, predictions of bioactivity have focused on particular subgroups, such as antimicrobial peptides. We hypothesized that bioactive peptides may share more general features, and assessed this by contrasting the predictive power of existing antimicrobial predictors as well as a novel general predictor, PeptideRanker, across different classes of peptides. We observed that existing antimicrobial predictors had reasonable predictive power to identify peptides of certain other classes i.e. toxin and venom peptides. We trained two general predictors of peptide bioactivity, one focused on short peptides (4–20 amino acids) and one focused on long peptides ( amino acids). These general predictors had performance that was typically as good as, or better than, that of specific predictors. We noted some striking differences in the features of short peptide and long peptide predictions, in particular, high scoring short peptides favour phenylalanine. This is consistent with the hypothesis that short and long peptides have different functional constraints, perhaps reflecting the difficulty for typical short peptides in supporting independent tertiary structure. We conclude that there are general shared features of bioactive peptides across different functional classes, indicating that computational prediction may accelerate the discovery of novel bioactive peptides and aid in the improved design of existing peptides, across many functional classes. An implementation of the predictive method, PeptideRanker, may be used to identify among a set of peptides those that may be more likely to be bioactive. PMID:23056189

Design and Conformational Analysis of Peptoids Containing N-Hydroxy Amides Reveals a Unique Sheet-Like Secondary Structure

PubMed Central

Crapster, J. Aaron; Stringer, Joseph R.; Guzei, Ilia A.; Blackwell, Helen E.

2011-01-01

N-hydroxy amides can be found in many naturally occurring and synthetic compounds and are known to act as both strong proton donors and chelators of metal cations. We have initiated studies of peptoids, or N-substituted glycines, that contain N-hydroxy amide side chains to investigate the potential effects of these functional groups on peptoid backbone amide rotamer equilibria and local conformations. We reasoned that the propensity of these functional groups to participate in hydrogen bonding could be exploited to enforce intramolecular or intermolecular interactions that yield new peptoid structures. Here, we report the design, synthesis, and detailed conformational analysis of a series of model N-hydroxy peptoids. These peptoids were readily synthesized, and their structures were analyzed in solution by 1D and 2D NMR and in the solid-state by X-ray crystallography. The N-hydroxy amides were found to strongly favor trans conformations with respect to the peptoid backbone in chloroform. More notably, unique sheet-like structures held together via intermolecular hydrogen bonds were observed in the X-ray crystal structures of an N-hydroxy amide peptoid dimer, which to our knowledge represent the first structure of this type reported for peptoids. These results suggest that the N-hydroxy amide can be utilized to control both local backbone geometries and longer-range intermolecular interactions in peptoids, and represents a new functional group in the peptoid design toolbox. PMID:22180908

Characterization of bioactive peptides obtained from marine invertebrates.

PubMed

Lee, Jung Kwon; Jeon, Joong-Kyun; Kim, Se-Kwon; Byun, Hee-Guk

2012-01-01

Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and by-products, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed. Copyright © 2012 Elsevier Inc. All rights reserved.

Biomimetic peptoid polymers

DOEpatents

Zuckermann, Ronald N.; Chu, Tammy K.; Nam, Ki Tae

2015-07-07

The present invention provides for novel peptoid oligomers that are capable of self-assembling into two-dimensional sheet structures. The peptoid oligomers can have alternately hydrophilic or polar side-chains and hydrophobic or apolar side-chains. The peptoid oligomers, and the two-dimensional sheet structures, can be applied to biological applications where the peptoid plays a role as a biological scaffold or building block. Also, the two-dimensional sheet structures of the present invention can be used as two-dimensional nanostructures in device applications.

Bioactive peptides derived from human milk proteins--mechanisms of action.

PubMed

Wada, Yasuaki; Lönnerdal, Bo

2014-05-01

Human milk contains a multitude of bioactive proteins with very diverse functions, which are beneficial for the rapidly growing neonate. The large variety of bioactivities is accomplished by the combination of bioactive proteins per se and gastrointestinal release of bioactive peptides derived from them. The bioactivities exerted by these peptides include enhancement of mineral absorption, immunomodulation, opioid, antihypertensive and antimicrobial activities. Notably, several of the activities are not attributed to the parental proteins, but exclusively to released bioactive peptides. This article reviews studies on bioactive peptides derived from major human milk proteins, such as caseins, α-lactalbumin and lactoferrin, during gastrointestinal digestion. Studies of bovine milk counterparts are also cited as a comparison. Copyright © 2014. Published by Elsevier Inc.

Bioactive peptides released from in vitro digestion of human milk with or without pasteurization.

PubMed

Wada, Yasuaki; Lönnerdal, Bo

2015-04-01

Pasteurized donor human milk (HM) serves as the best alternative for breast-feeding when availability of mother's milk is limited. Pasteurization is also applied to mother's own milk for very low birth weight infants, who are vulnerable to microbial infection. Whether pasteurization affects protein digestibility and therefore modulates the profile of bioactive peptides released from HM proteins by gastrointestinal digestion, has not been examined to date. HM with and without pasteurization (62.5 °C for 30 min) were subjected to in vitro gastrointestinal digestion, followed by peptidomic analysis to compare the formation of bioactive peptides. Some of the bioactive peptides, such as caseinophosphopeptide homologues, a possible opioid peptide (or propeptide), and an antibacterial peptide, were present in undigested HM and showed resistance to in vitro digestion, suggesting that these peptides are likely to exert their bioactivities in the gastrointestinal lumen, or be stably transported to target organs. In vitro digestion of HM released a large variety of bioactive peptides such as angiotensin I-converting enzyme-inhibitory, antioxidative, and immunomodulatory peptides. Bioactive peptides were released largely in the same manner with and without pasteurization. Provision of pasteurized HM may be as beneficial as breast-feeding in terms of milk protein-derived bioactive peptides.

Production of Bioactive Secondary Metabolites by Marine Vibrionaceae

PubMed Central

Mansson, Maria; Gram, Lone; Larsen, Thomas O.

2011-01-01

Bacteria belonging to the Vibrionaceae family are widespread in the marine environment. Today, 128 species of vibrios are known. Several of them are infamous for their pathogenicity or symbiotic relationships. Despite their ability to interact with eukaryotes, the vibrios are greatly underexplored for their ability to produce bioactive secondary metabolites and studies have been limited to only a few species. Most of the compounds isolated from vibrios so far are non-ribosomal peptides or hybrids thereof, with examples of N-containing compounds produced independent of nonribosomal peptide synthetases (NRPS). Though covering a limited chemical space, vibrios produce compounds with attractive biological activities, including antibacterial, anticancer, and antivirulence activities. This review highlights some of the most interesting structures from this group of bacteria. Many compounds found in vibrios have also been isolated from other distantly related bacteria. This cosmopolitan occurrence of metabolites indicates a high incidence of horizontal gene transfer, which raises interesting questions concerning the ecological function of some of these molecules. This account underlines the pending potential for exploring new bacterial sources of bioactive compounds and the challenges related to their investigation. PMID:22131950

Osteogenic differentiation of 3D cultured mesenchymal stem cells induced by bioactive peptides.

PubMed

Lukasova, Vera; Buzgo, Matej; Sovkova, Vera; Dankova, Jana; Rampichova, Michala; Amler, Evzen

2017-08-01

Bioactive peptides derived from receptor binding motifs of native proteins are a potent source of bioactive molecules that can induce signalling pathways. These peptides could substitute for osteogenesis promoting supplements. The work presented here compares three kinds of bioactive peptides derived from collagen III, bone morphogenetic protein 7 (BMP-7) and BMP-2 with their potential osteogenic activity on the model of porcine mesenchymal stem cells (pMSCs). pMSCs were cultured on electrospun polycaprolactone nanofibrous scaffolds with different concentrations of the bioactive peptides without addition of any osteogenic supplement. Analysis of pMSCs cultures included measurement of the metabolic activity and proliferation, immunofluorescence staining and also qPCR. Results showed no detrimental effect of the bioactive peptides to cultured pMSCs. Based on qPCR analysis, the bioactive peptides are specific for osteogenic differentiation with no detectable expression of collagen II. Our results further indicate that peptide derived from BMP-2 protein promoted the expression of mRNA for osteocalcin (OCN) and collagen I significantly compared to control groups and also supported deposition of OCN as observed by immunostaining method. The data suggest that bioactive peptide with an amino acid sequence of KIPKASSVPTELSAISTLYL derived from BMP-2 protein was the most potent for triggering osteogenic differentiation of pMSCs. © 2017 John Wiley & Sons Ltd.

Peptide profiling and the bioactivity character of yogurt in the simulated gastrointestinal digestion.

PubMed

Jin, Yan; Yu, Yang; Qi, Yanxia; Wang, Fangjun; Yan, Jiaze; Zou, Hanfa

2016-06-01

This study investigated the relationship between peptide profiles and the bioactivity character of yogurt in simulated gastrointestinal trials. A total of 250, 434 and 466 peptides were identified by LC-MS/MS analyses of yogurt, gastric digest and pancreatic digest. Forty peptides of yogurt survived in gastrointestinal digestion. κ-CN and β-CN contributed the diversity of peptides during the fermentation process and gastrointestinal digestion, respectively. The favorite of κ-CN by lactic acid bacteria complemented gut digestion by hydrolyzing κ-CN, the low abundance milk proteins. The potential bioactivities were evaluated by in vitro ACE and DPP-IV inhibition assays. The ACE inhibition rate of the pancreatic digests was ~4 - and ~2 - fold greater than that of yogurt and the gastric digests. The ACE inhibitory peptides generated during gastrointestinal digestion improved the ACE inhibitory activity of the gastric and pancreatic digests. The DPP-IV inhibition rate of the pancreatic digest was ~6 - and ~3 - fold greater than that of yogurt and the gastric digest. The numbers of potential DPP-IV inhibitory peptides were positively correlated to the DPP-IV inhibitory activity of the gastric and pancreatic digests. The present study describes the characters and bioactivities of peptides from yogurt in a simulated gastrointestinal digestion. The number of peptides identified from yogurt and gastrointestinal digests by LC-MS/MS increased in the simulated gastrointestinal trials. The in vitro ACE and DPP-IV inhibition bioactivities revealed that the bioactivity of yogurt was enhanced during gastrointestinal digestion. The correlation between peptides and bioactivity in vitro indicated that not only the peptides amount but also the proportion of peptides with high bioactivities contributed to increased bioactivity during gastrointestinal digestion. The study of peptides identified from yogurt and digests revealed that the number of released peptides was not determined by the abundance of the parent proteins but by whether the enzymes favored the protein. In summary, peptide profiling and bioactivities of yogurt in simulated gastrointestinal digestion helped to elucidate the health benefits of yogurt peptides. The results further revealed that pre-digestion of milk by lactic acid bacteria are complementary to generate bioactive peptides and to provide particular yogurt functions. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization, Preparation, and Purification of Marine Bioactive Peptides

PubMed Central

Wang, Xueqin; Yu, Huahua; Xing, Ronge

2017-01-01

Marine bioactive peptides, as a source of unique bioactive compounds, are the focus of current research. They exert various biological roles, some of the most crucial of which are antioxidant activity, antimicrobial activity, anticancer activity, antihypertensive activity, anti-inflammatory activity, and so forth, and specific characteristics of the bioactivities are described. This review also describes various manufacturing techniques for marine bioactive peptides using organic synthesis, microwave assisted extraction, chemical hydrolysis, and enzymes hydrolysis. Finally, purification of marine bioactive peptides is described, including gel or size exclusion chromatography, ion-exchange column chromatography, and reversed-phase high-performance liquid chromatography, which are aimed at finding a fast, simple, and effective method to obtain the target peptides. PMID:28761878

Evaluating the Effect of Peptoid Lipophilicity on Antimicrobial Potency, Cytotoxicity, and Combinatorial Library Design.

PubMed

Turkett, Jeremy A; Bicker, Kevin L

2017-04-10

Growing prevalence of antibiotic resistant bacterial infections necessitates novel antimicrobials, which could be rapidly identified from combinatorial libraries. We report the use of the peptoid library agar diffusion (PLAD) assay to screen peptoid libraries against the ESKAPE pathogens, including the optimization of assay conditions for each pathogen. Work presented here focuses on the tailoring of combinatorial peptoid library design through a detailed study of how peptoid lipophilicity relates to antibacterial potency and mammalian cell toxicity. The information gleaned from this optimization was then applied using the aforementioned screening method to examine the relative potency of peptoid libraries against Staphylococcus aureus, Acinetobacter baumannii, and Enterococcus faecalis prior to and following functionalization with long alkyl tails. The data indicate that overall peptoid hydrophobicity and not simply alkyl tail length is strongly correlated with mammalian cell toxicity. Furthermore, this work demonstrates the utility of the PLAD assay in rapidly evaluating the effect of molecular property changes in similar libraries.

Bioinformatics and peptidomics approaches to the discovery and analysis of food-derived bioactive peptides.

PubMed

Agyei, Dominic; Tsopmo, Apollinaire; Udenigwe, Chibuike C

2018-06-01

There are emerging advancements in the strategies used for the discovery and development of food-derived bioactive peptides because of their multiple food and health applications. Bioinformatics and peptidomics are two computational and analytical techniques that have the potential to speed up the development of bioactive peptides from bench to market. Structure-activity relationships observed in peptides form the basis for bioinformatics and in silico prediction of bioactive sequences encrypted in food proteins. Peptidomics, on the other hand, relies on "hyphenated" (liquid chromatography-mass spectrometry-based) techniques for the detection, profiling, and quantitation of peptides. Together, bioinformatics and peptidomics approaches provide a low-cost and effective means of predicting, profiling, and screening bioactive protein hydrolysates and peptides from food. This article discuses the basis, strengths, and limitations of bioinformatics and peptidomics approaches currently used for the discovery and analysis of food-derived bioactive peptides.

Enhancing bioactive peptide release and identification using targeted enzymatic hydrolysis of milk proteins.

PubMed

Nongonierma, Alice B; FitzGerald, Richard J

2018-06-01

Milk proteins have been extensively studied for their ability to yield a range of bioactive peptides following enzymatic hydrolysis/digestion. However, many hurdles still exist regarding the widespread utilization of milk protein-derived bioactive peptides as health enhancing agents for humans. These mostly arise from the fact that most milk protein-derived bioactive peptides are not highly potent. In addition, they may be degraded during gastrointestinal digestion and/or have a low intestinal permeability. The targeted release of bioactive peptides during the enzymatic hydrolysis of milk proteins may allow the generation of particularly potent bioactive hydrolysates and peptides. Therefore, the development of milk protein hydrolysates capable of improving human health requires, in the first instance, optimized targeted release of specific bioactive peptides. The targeted hydrolysis of milk proteins has been aided by a range of in silico tools. These include peptide cutters and predictive modeling linking bioactivity to peptide structure [i.e., molecular docking, quantitative structure activity relationship (QSAR)], or hydrolysis parameters [design of experiments (DOE)]. Different targeted enzymatic release strategies employed during the generation of milk protein hydrolysates are reviewed herein and their limitations are outlined. In addition, specific examples are provided to demonstrate how in silico tools may help in the identification and discovery of potent milk protein-derived peptides. It is anticipated that the development of novel strategies employing a range of in silico tools may help in the generation of milk protein hydrolysates containing potent and bioavailable peptides, which in turn may be used to validate their health promoting effects in humans. Graphical abstract The targeted enzymatic hydrolysis of milk proteins may allow the generation of highly potent and bioavailable bioactive peptides.

Bioactive peptides released by in vitro digestion of standard and hydrolyzed infant formulas.

PubMed

Wada, Yasuaki; Lönnerdal, Bo

2015-11-01

Hydrolyzed infant formulas serve as appropriate nutritional sources for infants afflicted with cow's milk allergy, and milk proteins in hydrolyzed formulas are industrially hydrolyzed extensively or partially. To investigate whether industrial hydrolysis may modulate the digestive trajectory of milk proteins, thereby releasing different profiles of bioactive peptides compared with standard formulas, both standard and hydrolyzed formulas were subjected to in vitro digestion and formation of bioactive peptides were compared. One standard, one extensively hydrolyzed, and one partially hydrolyzed infant formula were digested in vitro with pepsin and pancreatin, taking into account the higher gastric pH of infants, and the digesta were subjected to peptidomic analysis. The standard formula released a larger variety of bioactive peptides than from the hydrolyzed formulas, indicating that industrial hydrolysis of milk proteins may generally attenuate their indigenous bioactivities such as antibacterial, immuno-regulatory, and anti-oxidative activities. Conversely, industrial hydrolysis may facilitate the formation of bioactive peptides from hydrophobic proteins/regions such as β-LG and the "strategic zone" of β-CN, which encrypt bioactive peptides including a dipeptidyl dipeptidase-4-inhibitory, hypocholesterolemic, and opioid peptides. Infants fed hydrolyzed infant formulas may be influenced by milk protein-derived bioactive peptides in a manner different from those fed standard formula. Copyright © 2015 Elsevier Inc. All rights reserved.

Meat and fermented meat products as a source of bioactive peptides.

PubMed

Stadnik, Joanna; Kęska, Paulina

2015-01-01

Bioactive peptides are short amino acid sequences, that upon release from the parent protein may play different physiological roles, including antioxidant, antihypertensive, antimicrobial, and other bioactivities. They have been identified from a range of foods, including those of animal origin, e.g., milk and muscle sources (with pork, beef, or chicken and various species of fish and marine organism). Bioactive peptides are encrypted within the sequence of the parent protein molecule and latent until released and activated by enzymatic proteolysis, e.g. during gastrointestinal digestion or food processing. Bioactive peptides derived from food sources have the potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an overview of the muscle-derived bioactive peptides, especially those of fermented meats and the potential benefits of these bioactive compounds to human health.

Prospects in the use of aptamers for characterizing the structure and stability of bioactive proteins and peptides in food.

PubMed

Agyei, Dominic; Acquah, Caleb; Tan, Kei Xian; Hii, Hieng Kok; Rajendran, Subin R C K; Udenigwe, Chibuike C; Danquah, Michael K

2018-01-01

Food-derived bioactive proteins and peptides have gained acceptance among researchers, food manufacturers and consumers as health-enhancing functional food components that also serve as natural alternatives for disease prevention and/or management. Bioactivity in food proteins and peptides is determined by their conformations and binding characteristics, which in turn depend on their primary and secondary structures. To maintain their bioactivities, the molecular integrity of bioactive peptides must remain intact, and this warrants the study of peptide form and structure, ideally with robust, highly specific and sensitive techniques. Short single-stranded nucleic acids (i.e. aptamers) are known to have high affinity for cognate targets such as proteins and peptides. Aptamers can be produced cost-effectively and chemically derivatized to increase their stability and shelf life. Their improved binding characteristics and minimal modification of the target molecular signature suggests their suitability for real-time detection of conformational changes in both proteins and peptides. This review discusses the developmental progress of systematic evolution of ligands by exponential enrichment (SELEX), an iterative technology for generating cost-effective aptamers with low dissociation constants (K d ) for monitoring the form and structure of bioactive proteins and peptides. The review also presents case studies of this technique in monitoring the structural stability of bioactive peptide formulations to encourage applications in functional foods. The challenges and potential of aptamers in this research field are also discussed. Graphical abstract Advancing bioactive proteins and peptide functionality via aptameric ligands.

BioPepDB: an integrated data platform for food-derived bioactive peptides.

PubMed

Li, Qilin; Zhang, Chao; Chen, Hongjun; Xue, Jitong; Guo, Xiaolei; Liang, Ming; Chen, Ming

2018-03-12

Food-derived bioactive peptides play critical roles in regulating most biological processes and have considerable biological, medical and industrial importance. However, a large number of active peptides data, including sequence, function, source, commercial product information, references and other information are poorly integrated. BioPepDB is a searchable database of food-derived bioactive peptides and their related articles, including more than four thousand bioactive peptide entries. Moreover, BioPepDB provides modules of prediction and hydrolysis-simulation for discovering novel peptides. It can serve as a reference database to investigate the function of different bioactive peptides. BioPepDB is available at http://bis.zju.edu.cn/biopepdbr/ . The web page utilises Apache, PHP5 and MySQL to provide the user interface for accessing the database and predict novel peptides. The database itself is operated on a specialised server.

Bioactivation of particles

DOEpatents

Pinaud, Fabien [Berkeley, CA; King, David [San Francisco, CA; Weiss, Shimon [Los Angeles, CA

2011-08-16

Particles are bioactivated by attaching bioactivation peptides to the particle surface. The bioactivation peptides are peptide-based compounds that impart one or more biologically important functions to the particles. Each bioactivation peptide includes a molecular or surface recognition part that binds with the surface of the particle and one or more functional parts. The surface recognition part includes an amino-end and a carboxy-end and is composed of one or more hydrophobic spacers and one or more binding clusters. The functional part(s) is attached to the surface recognition part at the amino-end and/or said carboxy-end.

Bioactive Peptide of Marine Origin for the Prevention and Treatment of Non-Communicable Diseases

PubMed Central

Pangestuti, Ratih; Kim, Se-Kwon

2017-01-01

Non-communicable diseases (NCD) are the leading cause of death and disability worldwide. The four main leading causes of NCD are cardiovascular diseases, cancers, respiratory diseases and diabetes. Recognizing the devastating impact of NCD, novel prevention and treatment strategies are extensively sought. Marine organisms are considered as an important source of bioactive peptides that can exert biological functions to prevent and treatment of NCD. Recent pharmacological investigations reported cardio protective, anticancer, antioxidative, anti-diabetic, and anti-obesity effects of marine-derived bioactive peptides. Moreover, there is available evidence supporting the utilization of marine organisms and its bioactive peptides to alleviate NCD. Marine-derived bioactive peptides are alternative sources for synthetic ingredients that can contribute to a consumer’s well-being, as a part of nutraceuticals and functional foods. This contribution focus on the bioactive peptides derived from marine organisms and elaborates its possible prevention and therapeutic roles in NCD. PMID:28282929

Bioactive peptides from meat muscle and by-products: generation, functionality and application as functional ingredients.

PubMed

Lafarga, Tomas; Hayes, Maria

2014-10-01

Bioactive peptides are sequences of between 2-30 amino acids in length that impart a positive health effect to the consumer when ingested. They have been identified from a range of foods, including milk and muscle sources including beef, chicken, pork and marine muscles. The myriad of peptides identified from these sources have known antihypertensive, opioid, antioxidant, antithrombotic and other bioactivities. Indeed, bioactive peptides could play a role in the prevention of diseases associated with the development of metabolic syndrome and mental health diseases. The aim of this work is to present an overview of the bioactive peptides identified in muscle proteins and by-products generated during the processing of meat. The paper looks at the isolation, enrichment and characterisation strategies that have been employed to date to generate bioactive peptides and the potential future applications of these peptides in functional foods for the prevention of heart and mental health problems and obesity. Copyright © 2014 Elsevier Ltd. All rights reserved.

A Thermodynamic Description of the Adsorption of Simple Water-Soluble Peptoids to Silica.

PubMed

Calkins, Anna L; Yin, Jennifer; Rangel, Jacenda L; Landry, Madeleine R; Fuller, Amelia A; Stokes, Grace Y

2016-11-08

The first report of a water-soluble peptoid adsorbed to silica monitored by second harmonic generation (SHG) at the liquid/solid interface is presented here. The molecular insights gained from these studies will inform the design and preparation of novel peptoid coatings. Simple 6- and 15-residue peptoids were dissolved in phosphate buffered saline and adsorbed to bare silica surfaces. Equilibrium binding constants and relative surface concentrations of adsorbed peptoids were determined from fits to the Langmuir model. Complementary fluorescence spectroscopy studies were used to quantify the maximum surface excess. Binding constants, determined here by SHG, were comparable to those previously reported for cationic proteins and small molecules. Enthalpies and free energies of adsorption were determined to elucidate thermodynamic driving forces. Circular dichroism spectra confirm that minimal conformational changes occur when peptoids are adsorbed to silica while pH studies indicate that electrostatic interactions impact adsorption.

Identification and Relative Quantification of Bioactive Peptides Sequentially Released during Simulated Gastrointestinal Digestion of Commercial Kefir.

PubMed

Liu, Yufang; Pischetsrieder, Monika

2017-03-08

Health-promoting effects of kefir may be partially caused by bioactive peptides. To evaluate their formation or degradation during gastrointestinal digestion, we monitored changes of the peptide profile in a model of (1) oral, (2) gastric, and (3) small intestinal digestion of kefir. Matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy analyses revealed clearly different profiles between digests 2/3 and kefir/digest 1. Subsequent ultraperformance liquid chromatography-electrospray ionization-tandem mass spectrometry identified 92 peptides in total (25, 25, 43, and 30, partly overlapping in kefir and digests 1, 2, and 3, respectively), including 16 peptides with ascribed bioactivity. Relative quantification in scheduled multiple reaction monitoring mode showed that many bioactive peptides were released by simulated digestion. Most prominently, the concentration of angiotensin-converting enzyme inhibitor β-casein 203-209 increased approximately 10 000-fold after combined oral, gastric, and intestinal digestion. Thus, physiological digestive processes may promote bioactive peptide formation from proteins and oligopeptides in kefir. Furthermore, bioactive peptides present in certain compartments of the gastrointestinal tract may exert local physiological effects.

A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste

PubMed Central

Lemes, Ailton Cesar; Sala, Luisa; Ores, Joana da Costa; Braga, Anna Rafaela Cavalcante; Egea, Mariana Buranelo; Fernandes, Kátia Flávia

2016-01-01

Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries. PMID:27322241

SpirPep: an in silico digestion-based platform to assist bioactive peptides discovery from a genome-wide database.

PubMed

Anekthanakul, Krittima; Hongsthong, Apiradee; Senachak, Jittisak; Ruengjitchatchawalya, Marasri

2018-04-20

Bioactive peptides, including biological sources-derived peptides with different biological activities, are protein fragments that influence the functions or conditions of organisms, in particular humans and animals. Conventional methods of identifying bioactive peptides are time-consuming and costly. To quicken the processes, several bioinformatics tools are recently used to facilitate screening of the potential peptides prior their activity assessment in vitro and/or in vivo. In this study, we developed an efficient computational method, SpirPep, which offers many advantages over the currently available tools. The SpirPep web application tool is a one-stop analysis and visualization facility to assist bioactive peptide discovery. The tool is equipped with 15 customized enzymes and 1-3 miscleavage options, which allows in silico digestion of protein sequences encoded by protein-coding genes from single, multiple, or genome-wide scaling, and then directly classifies the peptides by bioactivity using an in-house database that contains bioactive peptides collected from 13 public databases. With this tool, the resulting peptides are categorized by each selected enzyme, and shown in a tabular format where the peptide sequences can be tracked back to their original proteins. The developed tool and webpages are coded in PHP and HTML with CSS/JavaScript. Moreover, the tool allows protein-peptide alignment visualization by Generic Genome Browser (GBrowse) to display the region and details of the proteins and peptides within each parameter, while considering digestion design for the desirable bioactivity. SpirPep is efficient; it takes less than 20 min to digest 3000 proteins (751,860 amino acids) with 15 enzymes and three miscleavages for each enzyme, and only a few seconds for single enzyme digestion. Obviously, the tool identified more bioactive peptides than that of the benchmarked tool; an example of validated pentapeptide (FLPIL) from LC-MS/MS was demonstrated. The web and database server are available at http://spirpepapp.sbi.kmutt.ac.th . SpirPep, a web-based bioactive peptide discovery application, is an in silico-based tool with an overview of the results. The platform is a one-stop analysis and visualization facility; and offers advantages over the currently available tools. This tool may be useful for further bioactivity analysis and the quantitative discovery of desirable peptides.

Gastrointestinal Endogenous Proteins as a Source of Bioactive Peptides - An In Silico Study

PubMed Central

Dave, Lakshmi A.; Montoya, Carlos A.; Rutherfurd, Shane M.; Moughan, Paul J.

2014-01-01

Dietary proteins are known to contain bioactive peptides that are released during digestion. Endogenous proteins secreted into the gastrointestinal tract represent a quantitatively greater supply of protein to the gut lumen than those of dietary origin. Many of these endogenous proteins are digested in the gastrointestinal tract but the possibility that these are also a source of bioactive peptides has not been considered. An in silico prediction method was used to test if bioactive peptides could be derived from the gastrointestinal digestion of gut endogenous proteins. Twenty six gut endogenous proteins and seven dietary proteins were evaluated. The peptides present after gastric and intestinal digestion were predicted based on the amino acid sequence of the proteins and the known specificities of the major gastrointestinal proteases. The predicted resultant peptides possessing amino acid sequences identical to those of known bioactive peptides were identified. After gastrointestinal digestion (based on the in silico simulation), the total number of bioactive peptides predicted to be released ranged from 1 (gliadin) to 55 (myosin) for the selected dietary proteins and from 1 (secretin) to 39 (mucin-5AC) for the selected gut endogenous proteins. Within the intact proteins and after simulated gastrointestinal digestion, angiotensin converting enzyme (ACE)-inhibitory peptide sequences were the most frequently observed in both the dietary and endogenous proteins. Among the dietary proteins, after in silico simulated gastrointestinal digestion, myosin was found to have the highest number of ACE-inhibitory peptide sequences (49 peptides), while for the gut endogenous proteins, mucin-5AC had the greatest number of ACE-inhibitory peptide sequences (38 peptides). Gut endogenous proteins may be an important source of bioactive peptides in the gut particularly since gut endogenous proteins represent a quantitatively large and consistent source of protein. PMID:24901416

Characterization and production of multifunctional cationic peptides derived from rice proteins.

PubMed

Taniguchi, Masayuki; Ochiai, Akihito

2017-04-01

Food proteins have been identified as a source of bioactive peptides. These peptides are inactive within the sequence of the parent protein and must be released during gastrointestinal digestion, fermentation, or food processing. Of bioactive peptides, multifunctional cationic peptides are more useful than other peptides that have specific activity in promotion of health and/or the treatment of diseases. We have identified and characterized cationic peptides from rice enzymes and proteins that possess multiple functions, including antimicrobial, endotoxin-neutralizing, arginine gingipain-inhibitory, and/or angiogenic activities. In particular, we have elucidated the contribution of cationic amino acids (arginine and lysine) in the peptides to their bioactivities. Further, we have discussed the critical parameters, particularly proteinase preparations and fractionation or purification, in the enzymatic hydrolysis process for producing bioactive peptides from food proteins. Using an ampholyte-free isoelectric focusing (autofocusing) technique as a tool for fractionation, we successfully prepared fractions containing cationic peptides with multiple functions.

Bioactive Carbohydrates and Peptides in Foods: An Overview of Sources, Downstream Processing Steps and Associated Bioactivities.

PubMed

Hayes, Maria; Tiwari, Brijesh K

2015-09-17

Bioactive peptides and carbohydrates are sourced from a myriad of plant, animal and insects and have huge potential for use as food ingredients and pharmaceuticals. However, downstream processing bottlenecks hinder the potential use of these natural bioactive compounds and add cost to production processes. This review discusses the health benefits and bioactivities associated with peptides and carbohydrates of natural origin and downstream processing methodologies and novel processes which may be used to overcome these.

Bioactive Carbohydrates and Peptides in Foods: An Overview of Sources, Downstream Processing Steps and Associated Bioactivities

PubMed Central

Hayes, Maria; Tiwari, Brijesh K.

2015-01-01

Bioactive peptides and carbohydrates are sourced from a myriad of plant, animal and insects and have huge potential for use as food ingredients and pharmaceuticals. However, downstream processing bottlenecks hinder the potential use of these natural bioactive compounds and add cost to production processes. This review discusses the health benefits and bioactivities associated with peptides and carbohydrates of natural origin and downstream processing methodologies and novel processes which may be used to overcome these. PMID:26393573

Investigating Endogenous Peptides and Peptidases using Peptidomics

PubMed Central

Tinoco, Arthur D.; Saghatelian, Alan

2012-01-01

Rather than simply being protein degradation products, peptides have proven to be important bioactive molecules. Bioactive peptides act as hormones, neurotransmitters and antimicrobial agents in vivo. The dysregulation of bioactive peptide signaling is also known to be involved in disease, and targeting peptide hormone pathways has been successful strategy in the development of novel therapeutics. The importance of bioactive peptides in biology has spurred research to elucidate the function and regulation of these molecules. Classical methods for peptide analysis have relied on targeted immunoassays, but certain scientific questions necessitated a broader and more detailed view of the peptidome–all the peptides in a cell, tissue or organism. In this review we discuss how peptidomics has emerged to fill this need through the application of advanced liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods that provide unique insights into peptide activity and regulation. PMID:21786763

Bioactive Properties of Maillard Reaction Products Generated From Food Protein-derived Peptides.

PubMed

Arihara, K; Zhou, L; Ohata, M

Food protein-derived peptides are promising food ingredients for developing functional foods, since various bioactive peptides are released from food proteins. The Maillard reaction, which plays an important role in most processed foods, generates various chemical components during processing. Although changes of amino acids or proteins and reduced sugars by the Maillard reaction have been studied extensively, such changes of peptides by the Maillard reaction are still not resolved enough. Since food protein-derived peptides are widely utilized in many processed foods, it deserves concern and research on the changes of peptides by the Maillard reaction in foods during processing or storage. This chapter initially overviewed food protein-derived bioactive peptides. Then, Maillard reaction products generated from peptides are discussed. We focused particularly on their bioactivities. © 2017 Elsevier Inc. All rights reserved.

Milk derived bioactive peptides and their impact on human health - A review.

PubMed

Mohanty, D P; Mohapatra, S; Misra, S; Sahu, P S

2016-09-01

Milk-derived bioactive peptides have been identified as potential ingredients of health-promoting functional foods. These bioactive peptides are targeted at diet-related chronic diseases especially the non-communicable diseases viz., obesity, cardiovascular diseases and diabetes. Peptides derived from the milk of cow, goat, sheep, buffalo and camel exert multifunctional properties, including anti-microbial, immune modulatory, anti-oxidant, inhibitory effect on enzymes, anti-thrombotic, and antagonistic activities against various toxic agents. Majority of those regulate immunological, gastrointestinal, hormonal and neurological responses, thereby playing a vital role in the prevention of cancer, osteoporosis, hypertension and other disorders as discussed in this review. For the commercial production of such novel bioactive peptides large scale technologies based on membrane separation and ion exchange chromatography methods have been developed. Separation and identification of those peptides and their pharmacodynamic parameters are necessary to transfer their potent functional properties into food applications. The present review summarizes the preliminary classes of bioactive milk-derived peptides along with their physiological functions, general characteristics and potential applications in health-care.

Self-Repair and Patterning of 2D Membrane-Like Peptoid Materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiao, Fang; Chen, Yulin; Jin, Haibao

2016-08-31

Two-dimensional materials are of increasing interest for use in filtration, sensing, nanoelectronics, and biomedical devices. Peptoids are a class of biomimetic sequence-defined polymers for which certain amphiphillic sequences self-assemble into 2D crystalline materials with properties that mimic those of cell membranes. Using in situ AFM to both dissect these membrane-like materials and image their subsequent behavior, we explore their ability to self-repair on a range of solid substrates. We show that, in a suitable range of pH, self-repair occurs on both negatively and positively charged substrates and can even occur in the absence of an underlying surface. Following dissection ofmore » pre-assembled peptoid membranes and upon introduction of a peptoid monomer solution, peptoids repair the damage by assembling at the newly created edges. The speed of the advancing edge depends on the edge orientation, reflecting the two-fold symmetry of the underlying peptoid lattice. Moreover, because the membranes are stabilized by hydrophobic interactions, if the solution contains peptoids possessing an identical sequence in the hydrophobic block but a distinct hydrophilic block, filling of the defects creates membranes that are patterned at the nanoscale. Consequently, we can utilize this ability to create nm-sized patterns of distinct functional groups within a single coherent membrane.« less

Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry.

PubMed

Kwok, Wai Him; Ho, Emmie N M; Lau, Ming Yip; Leung, Gary N W; Wong, April S Y; Wan, Terence S M

2013-03-01

In recent years, there has been an ongoing focus for both human and equine doping control laboratories on developing detection methods to control the misuse of peptide therapeutics. Immunoaffinity purification is a common extraction method to isolate peptides from biological matrices and obtain sufficient detectability in subsequent instrumental analysis. However, monoclonal or polyclonal antibodies for immunoaffinity purification may not be commercially available, and even if available, such antibodies are usually very costly. In our study, a simple mixed-mode anion exchange solid-phase extraction cartridge was employed for the extraction of seven target peptides (GHRP-1, GHRP-2, GHRP-6, ipamorelin, hexarelin, CJC-1295, and N-acetylated LKKTETQ (active ingredient of TB-500)) and their in vitro metabolites from horse plasma. The final extract was subject to ultra-high-performance liquid chromatographic separation and analysed with a hybrid high-resolution mass spectrometer. The limits of detection for all seven peptides were estimated to be less than 50 pg/mL. Method validation was performed with respect to specificity, precision, and recovery. The applicability of this multi-analyte method was demonstrated by the detection of N-acetylated LKKTETQ and its metabolite N-acetylated LK from plasma samples obtained after subcutaneous administration of TB-500 (10 mg N-acetylated LKKTETQ) to two thoroughbred geldings. This method could easily be modified to cover more bioactive peptides, such as dermorphin, β-casomorphin, and desmopressin. With the use of high-resolution mass spectrometry, the full-scan data acquired can also be re-processed retrospectively to search for peptides and their metabolites that have not been targeted at the time of analysis. To our knowledge, this is the first identification of in vitro metabolites of all the studied peptides other than TB-500 in horses.

Plant proteases for bioactive peptides release: A review.

PubMed

Mazorra-Manzano, M A; Ramírez-Suarez, J C; Yada, R Y

2017-04-10

Proteins are a potential source of health-promoting biomolecules with medical, nutraceutical, and food applications. Nowadays, bioactive peptides production, its isolation, characterization, and strategies for its delivery to target sites are a matter of intensive research. In vitro and in vivo studies regarding the bioactivity of peptides has generated strong evidence of their health benefits. Dairy proteins are considered the richest source of bioactive peptides, however proteins from animal and vegetable origin also have been shown to be important sources. Enzymatic hydrolysis has been the process most commonly used for bioactive peptide production. Most commercial enzymatic preparations frequently used are from animal (e.g., trypsin and pepsin) and microbial (e.g., Alcalase® and Neutrase®) sources. Although the use of plant proteases is still relatively limited to papain and bromelain from papaya and pineapple, respectively, the application of new plant proteases is increasing. This review presents the latest knowledge in the use and diversity of plant proteases for bioactive peptides release from food proteins including both available commercial plant proteases as well as new potential plant sources. Furthermore, the properties of peptides released by plant proteases and health benefits associated in the control of disorders such as hypertension, diabetes, obesity, and cancer are reviewed.

Functional significance of bioactive peptides derived from soybean.

PubMed

Singh, Brij Pal; Vij, Shilpa; Hati, Subrota

2014-04-01

Biologically active peptides play an important role in metabolic regulation and modulation. Several studies have shown that during gastrointestinal digestion, food processing and microbial proteolysis of various animals and plant proteins, small peptides can be released which possess biofunctional properties. These peptides are to prove potential health-enhancing nutraceutical for food and pharmaceutical applications. The beneficial health effects of bioactive peptides may be several like antihypertensive, antioxidative, antiobesity, immunomodulatory, antidiabetic, hypocholesterolemic and anticancer. Soybeans, one of the most abundant plant sources of dietary protein, contain 36-56% of protein. Recent studies showed that soy milk, an aqueous extract of soybean, and its fermented product have great biological properties and are a good source of bioactive peptides. This review focuses on bioactive peptides derived from soybean; we illustrate their production and biofunctional attributes. Copyright © 2014 Elsevier Inc. All rights reserved.

Peptoid nanosheets exhibit a new secondary-structure motif.

PubMed

Mannige, Ranjan V; Haxton, Thomas K; Proulx, Caroline; Robertson, Ellen J; Battigelli, Alessia; Butterfoss, Glenn L; Zuckermann, Ronald N; Whitelam, Stephen

2015-10-15

A promising route to the synthesis of protein-mimetic materials that are capable of complex functions, such as molecular recognition and catalysis, is provided by sequence-defined peptoid polymers--structural relatives of biologically occurring polypeptides. Peptoids, which are relatively non-toxic and resistant to degradation, can fold into defined structures through a combination of sequence-dependent interactions. However, the range of possible structures that are accessible to peptoids and other biological mimetics is unknown, and our ability to design protein-like architectures from these polymer classes is limited. Here we use molecular-dynamics simulations, together with scattering and microscopy data, to determine the atomic-resolution structure of the recently discovered peptoid nanosheet, an ordered supramolecular assembly that extends macroscopically in only two dimensions. Our simulations show that nanosheets are structurally and dynamically heterogeneous, can be formed only from peptoids of certain lengths, and are potentially porous to water and ions. Moreover, their formation is enabled by the peptoids' adoption of a secondary structure that is not seen in the natural world. This structure, a zigzag pattern that we call a Σ('sigma')-strand, results from the ability of adjacent backbone monomers to adopt opposed rotational states, thereby allowing the backbone to remain linear and untwisted. Linear backbones tiled in a brick-like way form an extended two-dimensional nanostructure, the Σ-sheet. The binary rotational-state motif of the Σ-strand is not seen in regular protein structures, which are usually built from one type of rotational state. We also show that the concept of building regular structures from multiple rotational states can be generalized beyond the peptoid nanosheet system.

Peptoid conformational free energy landscapes from implicit-solvent molecular simulations in AMBER.

PubMed

Voelz, Vincent A; Dill, Ken A; Chorny, Ilya

2011-01-01

To test the accuracy of existing AMBER force field models in predicting peptoid conformation and dynamics, we simulated a set of model peptoid molecules recently examined by Butterfoss et al. (JACS 2009, 131, 16798-16807) using QM methods as well as three peptoid sequences with experimentally determined structures. We found that AMBER force fields, when used with a Generalized Born/Surface Area (GBSA) implicit solvation model, could accurately reproduce the peptoid torsional landscape as well as the major conformers of known peptoid structures. Enhanced sampling by replica exchange molecular dynamics (REMD) using temperatures from 300 to 800 K was used to sample over cis-trans isomerization barriers. Compared to (Nrch)5 and cyclo-octasarcosyl, the free energy of N-(2-nitro-3-hydroxyl phenyl)glycine-N-(phenyl)glycine has the most "foldable" free energy landscape, due to deep trans-amide minima dictated by N-aryl sidechains. For peptoids with (S)-N (1-phenylethyl) (Nspe) side chains, we observe a discrepancy in backbone dihedral propensities between molecular simulations and QM calculations, which may be due to force field effects or the inability to capture n --> n* interactions. For these residues, an empirical phi-angle biasing potential can "rescue" the backbone propensities seen in QM. This approach can serve as a general strategy for addressing force fields without resorting to a complete reparameterization. Overall, this study demonstrates the utility of implicit-solvent REMD simulations for efficient sampling to predict peptoid conformational landscapes, providing a potential tool for first-principles design of sequences with specific folding properties.

Tuning calcite morphology and growth acceleration by a rational design of highly stable protein-mimetics

NASA Astrophysics Data System (ADS)

Chen, Chun-Long; Qi, Jiahui; Tao, Jinhui; Zuckermann, Ronald N.; Deyoreo, James J.

2014-09-01

In nature, proteins play a significant role in biomineral formation. One of the ultimate goals of bioinspired materials science is to develop highly stable synthetic molecules that mimic the function of these natural proteins by controlling crystal formation. Here, we demonstrate that both the morphology and the degree of acceleration or inhibition observed during growth of calcite in the presence of peptoids can be rationally tuned by balancing the electrostatic and hydrophobic interactions, with hydrophobic interactions playing the dominant role. While either strong electrostatic or hydrophobic interactions inhibit growth and reduces expression of the {104} faces, correlations between peptoid-crystal binding energies and observed changes in calcite growth indicate moderate electrostatic interactions allow peptoids to weakly adsorb while moderate hydrophobic interactions cause disruption of surface-adsorbed water layers, leading to growth acceleration with retained expression of the {104} faces. This study provides fundamental principles for designing peptoids as crystallization promoters, and offers a straightforward screening method based on macroscopic crystal morphology. Because peptoids are sequence-specific, highly stable, and easily synthesized, peptoid-enhanced crystallization offers a broad range of potential applications.

Tuning calcite morphology and growth acceleration by a rational design of highly stable protein-mimetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Chunlong; Qi, Jiahui; Tao, Jinhui

2014-09-05

In nature, proteins play a significant role in biomineral formation. One of the ultimate goals of bioinspired materials science is to develop highly stable synthetic molecules that mimic the function of these natural proteins by controlling crystal formation. Here, we demonstrate that both the morphology and the degree of acceleration or inhibition observed during growth of calcite in the presence of peptoids can be rationally tuned by balancing the electrostatic interactions (EI) and hydrophobic interactions (HI), with HI playing the dominant role. While either strong EI or HI inhibit growth and suppress (104) face expression, correlations between peptoid-crystal binding energiesmore » and observed changes in calcite growth indicate moderate EI allow peptoids to weakly adsorb while moderate HI cause disruption of surface-adsorbed water layers, leading to growth acceleration with retained expression of (104) faces. This study provides fundamental principles for designing peptoids as crystallization promoters, and offers a straightforward screening method based on macroscopic crystal morphology. Because peptoids are sequence-specific, highly stable, and easily synthesized, peptoid-enhanced crystallization offers a broad range of potential applications.« less

Tuning calcite morphology and growth acceleration by a rational design of highly stable protein-mimetics

PubMed Central

Chen, Chun-Long; Qi, Jiahui; Tao, Jinhui; Zuckermann, Ronald N.; DeYoreo, James J.

2014-01-01

In nature, proteins play a significant role in biomineral formation. One of the ultimate goals of bioinspired materials science is to develop highly stable synthetic molecules that mimic the function of these natural proteins by controlling crystal formation. Here, we demonstrate that both the morphology and the degree of acceleration or inhibition observed during growth of calcite in the presence of peptoids can be rationally tuned by balancing the electrostatic and hydrophobic interactions, with hydrophobic interactions playing the dominant role. While either strong electrostatic or hydrophobic interactions inhibit growth and reduces expression of the {104} faces, correlations between peptoid-crystal binding energies and observed changes in calcite growth indicate moderate electrostatic interactions allow peptoids to weakly adsorb while moderate hydrophobic interactions cause disruption of surface-adsorbed water layers, leading to growth acceleration with retained expression of the {104} faces. This study provides fundamental principles for designing peptoids as crystallization promoters, and offers a straightforward screening method based on macroscopic crystal morphology. Because peptoids are sequence-specific, highly stable, and easily synthesized, peptoid-enhanced crystallization offers a broad range of potential applications. PMID:25189418

Vegetable foods: a cheap source of proteins and peptides with antihypertensive, antioxidant, and other less occurrence bioactivities.

PubMed

García, M C; Puchalska, P; Esteve, C; Marina, M L

2013-03-15

Despite less explored than foods from animal origin, plant derived foods also contain biologically active proteins and peptides. Bioactive peptides can be present as an independent entity in the food or, more frequently, can be in a latent state as part of the sequence of a protein. Release from that protein requires protein hydrolysis by enzymatic digestion, fermentation or autolysis. Different methodologies have been used to test proteins and peptides bioactivities. Fractionation, separation, and identification techniques have also been employed for the isolation and identification of bioactive proteins or peptides. In this work, proteins and peptides from plant derived foods exerting antihypertensive, antioxidant, hypocholesterolemic, antithrombotic, and immunostimulating capacities or ability to reduce food intake have been reviewed. Copyright © 2013 Elsevier B.V. All rights reserved.

Peptidomics methods for the identification of peptidase-substrate interactions

PubMed Central

Lone, Anna Mari; Kim, Yun-Gon; Saghatelian, Alan

2013-01-01

Peptidases have important roles in controlling physiological signaling through their regulation of bioactive peptides. Understanding and controlling bioactive peptide regulation is of great biomedical interest and approaches that elucidate the interplay between peptidases and their substrates are vital for achieving this goal. Here, we highlight the utility of recent peptidomics approaches in identifying endogenous substrates of peptidases. These approaches reveal bioactive substrates and help characterize the biochemical functions of the enzyme. Most recently, peptidomics approaches have been applied to address the challenging question of identifying the peptidases responsible for regulating specific bioactive peptides. Since peptidases are of great biomedical interest, these approaches will begin to impact our ability to identify new drug targets that regulate important bioactive peptides. PMID:23332665

Therapeutic potential of dairy bioactive peptides: A contemporary perspective.

PubMed

Sultan, Saira; Huma, Nuzhat; Butt, Masood Sadiq; Aleem, Muhammad; Abbas, Munawar

2018-01-02

Dairy products are associated with numerous health benefits. These are a good source of nutrients such as carbohydrates, protein (bioactive peptides), lipids, minerals, and vitamins, which are essential for growth, development, and maintenance of the human body. Accordingly, dairy bioactive peptides are one of the targeted compounds present in different dairy products. Dairy bioactive compounds can be classified as antihypertensive, anti-oxidative, immmunomodulant, anti-mutagenic, antimicrobial, opoid, anti-thrombotic, anti-obesity, and mineral-binding agents, depending upon biological functions. These bioactive peptides can easily be produced by enzymatic hydrolysis, and during fermentation and gastrointestinal digestion. For this reason, fermented dairy products, such as yogurt, cheese, and sour milk, are gaining popularity worldwide, and are considered excellent source of dairy peptides. Furthermore, fermented and non-fermented dairy products are associated with lower risks of hypertension, coagulopathy, stroke, and cancer insurgences. The current review article is an attempt to disseminate general information about dairy peptides and their health claims to scientists, allied stakeholders, and, certainly, readers.

BIOPEP database and other programs for processing bioactive peptide sequences.

PubMed

Minkiewicz, Piotr; Dziuba, Jerzy; Iwaniak, Anna; Dziuba, Marta; Darewicz, Małgorzata

2008-01-01

This review presents the potential for application of computational tools in peptide science based on a sample BIOPEP database and program as well as other programs and databases available via the World Wide Web. The BIOPEP application contains a database of biologically active peptide sequences and a program enabling construction of profiles of the potential biological activity of protein fragments, calculation of quantitative descriptors as measures of the value of proteins as potential precursors of bioactive peptides, and prediction of bonds susceptible to hydrolysis by endopeptidases in a protein chain. Other bioactive and allergenic peptide sequence databases are also presented. Programs enabling the construction of binary and multiple alignments between peptide sequences, the construction of sequence motifs attributed to a given type of bioactivity, searching for potential precursors of bioactive peptides, and the prediction of sites susceptible to proteolytic cleavage in protein chains are available via the Internet as are other approaches concerning secondary structure prediction and calculation of physicochemical features based on amino acid sequence. Programs for prediction of allergenic and toxic properties have also been developed. This review explores the possibilities of cooperation between various programs.

Marine-Derived Bioactive Peptides for Biomedical Sectors: A Review.

PubMed

Ruiz-Ruiz, Federico; Mancera-Andrade, Elena I; Iqbal, Hafiz M N

2017-01-01

Marine-based resources such as algae and other marine by-products have been recognized as rich sources of structurally diverse bioactive peptides. Evidently, their structural characteristics including unique amino acid residues are responsible for their biological activity. Several of the above-mentioned marine-origin species show multi-functional bioactivities that are useful for a new discovery and/or reinvention of biologically active ingredients, nutraceuticals and/or pharmaceuticals. Therefore, in recent years, marine-derived bioactive peptides have gained a considerable attention with high-value biomedical and/or pharmaceutical potentials. Furthermore, a wider spectrum of bioactive peptides can be produced through proteolytic-assisted hydrolysis of various marine resources under controlled physicochemical (pH and temperature of the reaction media) environment. Owing to their numerous health-related beneficial effects and therapeutic potential in the treatment and/or prevention of many diseases, such marine-derived bioactive peptides exhibit a wider spectrum of biological activities such as anti-cancerous, anti-proliferative, anti-coagulant, antibacterial, antifungal, and anti-tumor activities among many others. Based on emerging evidence of marine-derived peptide mining, the above-mentioned marine resources contain noteworthy levels of high-value protein. The present review article mainly summarizes the marine-derived bioactive peptides and emphasizing their potential applications in biomedical and/or pharmaceutical sectors of the modern world. In conclusion, recent literature has provided evidence that marine-derived bioactive peptides play a critical role in human health along with many possibilities of designing new functional nutraceuticals and/or pharmaceuticals to clarify potent mechanisms of action for a wider spectrum of diseases. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Constructing bioactive peptides with pH-dependent activities.

PubMed

Tu, Zhigang; Volk, Melanie; Shah, Khushali; Clerkin, Kevin; Liang, Jun F

2009-08-01

Many bioactive peptides are featured by their arginine and lysine rich contents. In this study, lysine and arginine residues in lytic peptides were selectively replaced by histidines. Although resulting histidine-containing lytic peptides had decreased activity, they did show pH-dependent cytotoxicity. The activity of the constructed histidine-containing lytic peptides increased 2-8 times as the solution pH changed from 7.4 to 5.5. More importantly, these histidine-containing peptides maintain the same cell killing mechanism as their parent peptides by causing cell lysis. Both the activity and pH-sensitivity of histidine-containing peptides are tunable by adjusting histidine substitution numbers and positions. This study has presented a general strategy to create bioactive peptides with desired pH-sensitivity to meet the needs of various applications such as cancer treatments.

Fungal Secretome Analysis via PepSAVI-MS: Identification of the Bioactive Peptide KP4 from Ustilago maydis

NASA Astrophysics Data System (ADS)

Kirkpatrick, Christine L.; Parsley, Nicole C.; Bartges, Tessa E.; Cooke, Madeline E.; Evans, Wilaysha S.; Heil, Lilian R.; Smith, Thomas J.; Hicks, Leslie M.

2018-05-01

Fungal secondary metabolites represent a rich and largely untapped source for bioactive molecules, including peptides with substantial structural diversity and pharmacological potential. As methods proceed to take a deep dive into fungal genomes, complimentary methods to identify bioactive components are required to keep pace with the expanding fungal repertoire. We developed PepSAVI-MS to expedite the search for natural product bioactive peptides and herein demonstrate proof-of-principle applicability of the pipeline for the discovery of bioactive peptides from fungal secretomes via identification of the antifungal killer toxin KP4 from Ustilago maydis P4. This work opens the door to investigating microbial secretomes with a new lens, and could have broad applications across human health, agriculture, and food safety. [Figure not available: see fulltext.

Fungal Secretome Analysis via PepSAVI-MS: Identification of the Bioactive Peptide KP4 from Ustilago maydis

NASA Astrophysics Data System (ADS)

Kirkpatrick, Christine L.; Parsley, Nicole C.; Bartges, Tessa E.; Cooke, Madeline E.; Evans, Wilaysha S.; Heil, Lilian R.; Smith, Thomas J.; Hicks, Leslie M.

2018-02-01

Fungal secondary metabolites represent a rich and largely untapped source for bioactive molecules, including peptides with substantial structural diversity and pharmacological potential. As methods proceed to take a deep dive into fungal genomes, complimentary methods to identify bioactive components are required to keep pace with the expanding fungal repertoire. We developed PepSAVI-MS to expedite the search for natural product bioactive peptides and herein demonstrate proof-of-principle applicability of the pipeline for the discovery of bioactive peptides from fungal secretomes via identification of the antifungal killer toxin KP4 from Ustilago maydis P4. This work opens the door to investigating microbial secretomes with a new lens, and could have broad applications across human health, agriculture, and food safety. [Figure not available: see fulltext.

Bioactive peptides derived from natural proteins with respect to diversity of their receptors and physiological effects.

PubMed

Yoshikawa, Masaaki

2015-10-01

We have found various bioactive peptides derived from animal and plant proteins, which interact with receptors for endogenous bioactive peptides such as opioids, neurotensin, complements C3a and C5a, oxytocin, and formyl peptides etc. Among them, rubiscolin, a δ opioid peptide derived from plant RuBisCO, showed memory-consolidating, anxiolytic-like, and food intake-modulating effects. Soymorphin, a μ opioid peptide derived from β-conglycinin showed anxiolytic-like, anorexigenic, hypoglycemic, and hypotriglyceridemic effects. β-Lactotensin derived from β-lactoglobulin, the first natural ligand for the NTS2 receptor, showed memory-consolidating, anxiolytic-like, and hypocholesterolemic effects. Weak agonist peptides for the complements C3a and C5a receptors were released from many proteins and exerted various central effects. Peptides showing anxiolytic-like antihypertensive and anti-alopecia effects via different types of receptors such as OT, FPR and AT2 were also obtained. Based on these study, new functions and post-receptor mechanisms of receptor commom to endogenous and exogenous bioactive peptides have been clarified. Copyright © 2015 Elsevier Inc. All rights reserved.

Biologically Active and Antimicrobial Peptides from Plants

PubMed Central

Salas, Carlos E.; Badillo-Corona, Jesus A.; Ramírez-Sotelo, Guadalupe; Oliver-Salvador, Carmen

2015-01-01

Bioactive peptides are part of an innate response elicited by most living forms. In plants, they are produced ubiquitously in roots, seeds, flowers, stems, and leaves, highlighting their physiological importance. While most of the bioactive peptides produced in plants possess microbicide properties, there is evidence that they are also involved in cellular signaling. Structurally, there is an overall similarity when comparing them with those derived from animal or insect sources. The biological action of bioactive peptides initiates with the binding to the target membrane followed in most cases by membrane permeabilization and rupture. Here we present an overview of what is currently known about bioactive peptides from plants, focusing on their antimicrobial activity and their role in the plant signaling network and offering perspectives on their potential application. PMID:25815307

A Dereplication and Bioguided Discovery Approach to Reveal New Compounds from a Marine-Derived Fungus Stilbella fimetaria

PubMed Central

Kildgaard, Sara; Subko, Karolina; Phillips, Emma; Goidts, Violaine; de la Cruz, Mercedes; Díaz, Caridad; Gotfredsen, Charlotte H.; Frisvad, Jens C.; Nielsen, Kristian F.; Larsen, Thomas O.

2017-01-01

A marine-derived Stilbella fimetaria fungal strain was screened for new bioactive compounds based on two different approaches: (i) bio-guided approach using cytotoxicity and antimicrobial bioassays; and (ii) dereplication based approach using liquid chromatography with both diode array detection and high resolution mass spectrometry. This led to the discovery of several bioactive compound families with different biosynthetic origins, including pimarane-type diterpenoids and hybrid polyketide-non ribosomal peptide derived compounds. Prefractionation before bioassay screening proved to be a great aid in the dereplication process, since separate fractions displaying different bioactivities allowed a quick tentative identification of known antimicrobial compounds and of potential new analogues. A new pimarane-type diterpene, myrocin F, was discovered in trace amounts and displayed cytotoxicity towards various cancer cell lines. Further media optimization led to increased production followed by the purification and bioactivity screening of several new and known pimarane-type diterpenoids. A known broad-spectrum antifungal compound, ilicicolin H, was purified along with two new analogues, hydroxyl-ilicicolin H and ilicicolin I, and their antifungal activity was evaluated. PMID:28805711

Bioactive factor delivery strategies from engineered polymer hydrogels for therapeutic medicine

PubMed Central

Nguyen, Minh Khanh; Alsberg, Eben

2014-01-01

Polymer hydrogels have been widely explored as therapeutic delivery matrices because of their ability to present sustained, localized and controlled release of bioactive factors. Bioactive factor delivery from injectable biopolymer hydrogels provides a versatile approach to treat a wide variety of diseases, to direct cell function and to enhance tissue regeneration. The innovative development and modification of both natural-(e.g., alginate (ALG), chitosan, hyaluronic acid (HA), gelatin, heparin (HEP), etc.) and synthetic-(e.g., polyesters, polyethyleneimine (PEI), etc.) based polymers has resulted in a variety of approaches to design drug delivery hydrogel systems from which loaded therapeutics are released. This review presents the state-of-the-art in a wide range of hydrogels that are formed though self-assembly of polymers and peptides, chemical crosslinking, ionic crosslinking and biomolecule recognition. Hydrogel design for bioactive factor delivery is the focus of the first section. The second section then thoroughly discusses release strategies of payloads from hydrogels for therapeutic medicine, such as physical incorporation, covalent tethering, affinity interactions, on demand release and/or use of hybrid polymer scaffolds, with an emphasis on the last 5 years. PMID:25242831

Peptidomic strategy for purification and identification of potential ACE-inhibitory and antioxidant peptides in Tetradesmus obliquus microalgae.

PubMed

Montone, Carmela Maria; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Piovesana, Susy; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2018-06-01

Microalgae are unicellular marine organisms that have promoted complex biochemical pathways to survive in greatly competitive marine environments. They could contain significant amounts of high-quality proteins which, because of their structural diversity, contain a range of yet undiscovered novel bioactive peptides. In this work, a peptidomic platform was developed for the separation and identification of bioactive peptides in protein hydrolysates. In this work, a peptidomic platform was developed for the extraction, separation, and identification of bioactive peptides in protein hydrolysates. Indeed, extraction of proteins from recalcitrant tissues is still a challenge due to their strong cell walls and high levels of non-protein interfering compounds. Therefore, seven different protein extraction protocols, based on mechanical and chemical methods, were tested in order to produce high-quality protein extracts. Proteins obtained by means of the best protocol, consisting of milling the recalcitrant tissue with glass beads, were subjected to enzymatic digestion with Alcalase® and subsequently the hydrolysate was purified by two-dimensional semi-preparative reversed phase liquid chromatography. Fractions were assayed for antioxidant and antihypertensive activities and only the most active ones were finally analyzed by RP nanoHPLC-MS/MS. Around 500 peptide sequences were identified in these fractions. The identified peptides were subjected to an in silico analysis by PeptideRanker algorithm in order to assign a score of bioactivity probability. Twenty-five sequenced peptides were found with potential antioxidant and angiotensin-converting-enzyme-inhibitory activities. Four of these peptides, WPRGYFL, GPDRPKFLGPF, WYGPDRPKFL, SDWDRF, were selected for synthesis and in vitro tested for specific bioactivity, exhibiting good values of antioxidant and ACE-inhibitory activity. Graphical abstract Workflow showing the entire peptidomic approach developed for identification of bioactive peptides in microalgae.

Conformations of peptoids in nanosheets result from the interplay of backbone energetics and intermolecular interactions.

PubMed

Edison, John R; Spencer, Ryan K; Butterfoss, Glenn L; Hudson, Benjamin C; Hochbaum, Allon I; Paravastu, Anant K; Zuckermann, Ronald N; Whitelam, Stephen

2018-05-29

The conformations adopted by the molecular constituents of a supramolecular assembly influence its large-scale order. At the same time, the interactions made in assemblies by molecules can influence their conformations. Here we study this interplay in extended flat nanosheets made from nonnatural sequence-specific peptoid polymers. Nanosheets exist because individual polymers can be linear and untwisted, by virtue of polymer backbone elements adopting alternating rotational states whose twists oppose and cancel. Using molecular dynamics and quantum mechanical simulations, together with experimental data, we explore the design space of flat nanostructures built from peptoids. We show that several sets of peptoid backbone conformations are consistent with their being linear, but the specific combination observed in experiment is determined by a combination of backbone energetics and the interactions made within the nanosheet. Our results provide a molecular model of the peptoid nanosheet consistent with all available experimental data and show that its structure results from a combination of intra- and intermolecular interactions.

Photophysical properties of fluorescently-labeled peptoids.

PubMed

Rudat, Birgit; Birtalan, Esther; Vollrath, Sidonie B L; Fritz, Daniel; Kölmel, Dominik K; Nieger, Martin; Schepers, Ute; Müllen, Klaus; Eisler, Hans-Jürgen; Lemmer, Uli; Bräse, Stefan

2011-09-01

Fluorescently-labeled biomolecules are often utilized in biochemical or cellular experiments without further detailed spectroscopical characterization. This report is intended to narrow this gap and therefore presents the photophysical investigation of a library of 17 fluorescently-labeled molecules, namely peptoid transporters. First, one peptoid structure is labeled with seven different fluorophores and the spectroscopical properties are examined. Absorption and fluorescence maxima are almost identical for free dyes and conjugated dyes, suggesting free choice of a spectrally suitable fluorophore for different applications. Otherwise, extinction coefficients and quantum yields, and therefore the brightness of all seven dyes are strongly influenced. For the fluorophores, e.g. rhodamine B, the extent of this influence depends on the peptoid itself. This is shown by comparing different structures in the second part of this report. Especially the side chain functionalities influence the brightness. And finally, peptoids having two identical fluorescent labels are presented, which show decreased quantum yields. Possible reasons for the observed photophysical properties are discussed. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Antiamyloidogenic Activity of Aβ42-Binding Peptoid in Modulating Amyloid Oligomerization.

PubMed

Zhao, Zijian; Zhu, Ling; Li, Haiyun; Cheng, Peng; Peng, Jiaxi; Yin, Yudan; Yang, Yang; Wang, Chen; Hu, Zhiyuan; Yang, Yanlian

2017-01-01

The oligomerization and aggregation of amyloid β (Aβ) play central role in the pathogenesis of Alzheimer's disease (AD). Molecular binding agents for modulating the formation of Aβ oligomers and fibrils have promising application potential in AD therapies. By screening a peptoid library using surface plasmon resonance imaging, amyloid inhibitory peptoid 1 (AIP1) that has high affinity to Aβ42 is identified. AIP1 is demonstrated to inhibit Aβ42 oligomerization and fibrillation and to rescue Aβ42-induced cytotoxicity through decreasing the content of Aβ42 oligomers that is related to cell membrane permeability. Molecular docking suggests that the binding sites of AIP1 may be at the N-terminus of Aβ42. The blood-brain barrier (BBB) permeability of AIP1 using an in vitro BBB model is also revealed. This work provides a strategy for the design and development of peptoid-based antiamyloidogenic agents. The obtained amyloid inhibitory peptoid shows prospects in the therapeutic application in AD. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Highly stable and self-repairing membrane-mimetic 2D nanomaterials assembled from lipid-like peptoids

PubMed Central

Jin, Haibao; Jiao, Fang; Daily, Michael D.; Chen, Yulin; Yan, Feng; Ding, Yan-Huai; Zhang, Xin; Robertson, Ellen J.; Baer, Marcel D.; Chen, Chun-Long

2016-01-01

An ability to develop sequence-defined synthetic polymers that both mimic lipid amphiphilicity for self-assembly of highly stable membrane-mimetic 2D nanomaterials and exhibit protein-like functionality would revolutionize the development of biomimetic membranes. Here we report the assembly of lipid-like peptoids into highly stable, crystalline, free-standing and self-repairing membrane-mimetic 2D nanomaterials through a facile crystallization process. Both experimental and molecular dynamics simulation results show that peptoids assemble into membranes through an anisotropic formation process. We further demonstrated the use of peptoid membranes as a robust platform to incorporate and pattern functional objects through large side-chain diversity and/or co-crystallization approaches. Similar to lipid membranes, peptoid membranes exhibit changes in thickness upon exposure to external stimuli; they can coat surfaces in single layers and self-repair. We anticipate that this new class of membrane-mimetic 2D nanomaterials will provide a robust matrix for development of biomimetic membranes tailored to specific applications. PMID:27402325

Instructing cells with programmable peptide DNA hybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, Ronit; Stephanopoulos, Nicholas; Alvarez, Zaida

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the abilitymore » to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.« less

Instructing cells with programmable peptide DNA hybrids

DOE PAGES

Freeman, Ronit; Stephanopoulos, Nicholas; Alvarez, Zaida; ...

2017-07-10

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the abilitymore » to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.« less

Instructing cells with programmable peptide DNA hybrids

NASA Astrophysics Data System (ADS)

Freeman, Ronit; Stephanopoulos, Nicholas; Álvarez, Zaida; Lewis, Jacob A.; Sur, Shantanu; Serrano, Chris M.; Boekhoven, Job; Lee, Sungsoo S.; Stupp, Samuel I.

2017-07-01

The native extracellular matrix is a space in which signals can be displayed dynamically and reversibly, positioned with nanoscale precision, and combined synergistically to control cell function. Here we describe a molecular system that can be programmed to control these three characteristics. In this approach we immobilize peptide-DNA (P-DNA) molecules on a surface through complementary DNA tethers directing cells to adhere and spread reversibly over multiple cycles. The DNA can also serve as a molecular ruler to control the distance-dependent synergy between two peptides. Finally, we use two orthogonal DNA handles to regulate two different bioactive signals, with the ability to independently up- or downregulate each over time. This enabled us to discover that neural stem cells, derived from the murine spinal cord and organized as neurospheres, can be triggered to migrate out in response to an exogenous signal but then regroup into a neurosphere as the signal is removed.

Egg and Soy-Derived Peptides and Hydrolysates: A Review of Their Physiological Actions against Diabetes and Obesity.

PubMed

C de Campos Zani, Stepheny; Wu, Jianping; B Chan, Catherine

2018-04-28

Type 2 diabetes and obesity are two chronic conditions associated with the metabolic syndrome and their prevalences are increasing worldwide. The investigation of food protein-derived bioactive peptides that can improve the pathophysiology of diabetes or obesity while causing minimal side effects is desired. Egg and soy proteins generate bioactive peptides with multiple biological effects, exerting nutritional and physiological benefits. This review focuses on the anti-diabetic and anti-obesity effects of egg- and soy-derived peptides and hydrolysates in vivo and in vitro relevant to these conditions. Studies using the intact protein were considered only when comparing the results with the hydrolysate or peptides. In vivo evidence suggests that bioactive peptides from egg and soy can potentially be used to manage elements of glucose homeostasis in metabolic syndrome; however, the mechanisms of action on glucose and insulin metabolism, and the interaction between peptides and their molecular targets remain unclear. Optimizing the production of egg- and soy-derived peptides and standardizing the physiological models to study their effects on diabetes and obesity could help to clarify the effects of these bioactive peptides in metabolic syndrome-related conditions.

[Elaboration of Pseudo-natural Products Using Artificial In Vitro Biosynthesis Systems].

PubMed

Goto, Yuki

2018-01-01

 Peptidic natural products often consist of not only proteinogenic building blocks but also unique non-proteinogenic structures such as macrocyclic scaffolds and N-methylated backbones. Since such non-proteinogenic structures are important structural motifs that contribute to diverse bioactivity, we have proposed that peptides with non-proteinogenic structures should be attractive candidates as artificial bioactive peptides mimicking natural products, or so-called pseudo-natural products. We previously devised an engineered translation system for pseudo-natural peptides, referred to as the flexible in vitro translation (FIT) system. This system enabled "one-pot" synthesis of highly diverse pseudo-natural peptide libraries, which can be rapidly screened by mRNA display technology for the discovery of pseudo-natural peptides with diverse bioactivities.

Maize Bioactive Peptides against Cancer

NASA Astrophysics Data System (ADS)

Díaz-Gómez, Jorge L.; Castorena-Torres, Fabiola; Preciado-Ortiz, Ricardo E.; García-Lara, Silverio

2017-06-01

Cancer is one of the main chronic degenerative diseases worldwide. In recent years, consumption of whole-grain cereals and their derived food products has been associated with reduction risks of various types of cancer. Cereals main biomolecules includes proteins, peptides, and amino acids present in different quantities within the grain. The nutraceutical properties associated with peptides exerts biological functions that promote health and prevent this disease. In this review, we report the current status and advances on maize peptides regarding bioactive properties that have been reported such as antioxidant, antihypertensive, hepatoprotective, and anti-tumour activities. We also highlighted its biological potential through which maize bioactive peptides exert anti-cancer activity. Finally, we analyse and emphasize the possible areas of application for maize peptides.

Analysis of the proteolysis of bioactive peptides using a peptidomics approach

PubMed Central

Kim, Yun-Gon; Lone, Anna Mari; Saghatelian, Alan

2014-01-01

Identifying the peptidases that inactivate bioactive peptides (e.g. peptide hormones and neuropeptides) in mammals is an important unmet challenge. This protocol describes a recent approach that combines liquid chromatography-mass spectrometry peptidomics to identify endogenous cleavage sites of a bioactive peptide, the subsequent biochemical purification of a candidate peptidase based on these cleavage sites, and validation of the candidate peptidase’s role in the physiological regulation of the bioactive peptide by examining a peptidase knockout mouse. We highlight successful application of this protocol to discover that insulin-degrading enzyme (IDE) regulates physiological calcitonin gene-related peptide (CGRP) levels and detail the key stages and steps in this approach. This protocol requires 7 days of work; however, the total time for this protocol is highly variable because of its dependence on the availability of biological reagents, namely purified enzymes and knockout mice. The protocol is valuable because it expedites the characterization of mammalian peptidases, such as IDE, which in certain instances can be used to develop novel therapeutics. PMID:23949379

Marine Peptides as Potential Agents for the Management of Type 2 Diabetes Mellitus-A Prospect.

PubMed

Xia, En-Qin; Zhu, Shan-Shan; He, Min-Jing; Luo, Fei; Fu, Cheng-Zhan; Zou, Tang-Bin

2017-03-23

An increasing prevalence of diabetes is known as a main risk for human health in the last future worldwide. There is limited evidence on the potential management of type 2 diabetes mellitus using bioactive peptides from marine organisms, besides from milk and beans. We summarized here recent advances in our understanding of the regulation of glucose metabolism using bioactive peptides from natural proteins, including regulation of insulin-regulated glucose metabolism, such as protection and reparation of pancreatic β-cells, enhancing glucose-stimulated insulin secretion and influencing the sensitivity of insulin and the signaling pathways, and inhibition of bioactive peptides to dipeptidyl peptidase IV, α-amylase and α-glucosidase activities. The present paper tried to understand the underlying mechanism involved and the structure characteristics of bioactive peptides responsible for its antidiabetic activities to prospect the utilization of rich marine organism proteins.

Bioactive Proteins and Peptides from Soybeans.

PubMed

Agyei, Dominic

2015-01-01

Dietary proteins from soybeans have been shown to offer health benefits in vivo and/or in vitro either as intact proteins or in partially digested forms also called bioactive peptides. Upon oral administration and absorption, soy-derived bioactive peptides may induce several physiological responses such as antioxidative, antimicrobial, antihypertensive, anticancer and immunomodulatory effects. There has therefore been a mounting research interest in the therapeutic potential of soy protein hydrolysates and their subsequent incorporation in functional foods and 'Food for Specified Health Uses' (FOSHU) related products where their biological activities may assist in the promotion of good health or in the control and prevention of diseases. This mini review discusses relevant patents and gives an overview on bioactive proteins and peptides obtainable from soybeans. Processes for the production and formulation of these peptides are given, together with specific examples of their therapeutic potential and possible areas of application.

Marine Peptides as Potential Agents for the Management of Type 2 Diabetes Mellitus—A Prospect

PubMed Central

Xia, En-Qin; Zhu, Shan-Shan; He, Min-Jing; Luo, Fei; Fu, Cheng-Zhan; Zou, Tang-Bin

2017-01-01

An increasing prevalence of diabetes is known as a main risk for human health in the last future worldwide. There is limited evidence on the potential management of type 2 diabetes mellitus using bioactive peptides from marine organisms, besides from milk and beans. We summarized here recent advances in our understanding of the regulation of glucose metabolism using bioactive peptides from natural proteins, including regulation of insulin-regulated glucose metabolism, such as protection and reparation of pancreatic β-cells, enhancing glucose-stimulated insulin secretion and influencing the sensitivity of insulin and the signaling pathways, and inhibition of bioactive peptides to dipeptidyl peptidase IV, α-amylase and α-glucosidase activities. The present paper tried to understand the underlying mechanism involved and the structure characteristics of bioactive peptides responsible for its antidiabetic activities to prospect the utilization of rich marine organism proteins. PMID:28333091

In vivo digestomics of milk proteins in human milk and infant formula using a suckling rat pup model.

PubMed

Wada, Yasuaki; Phinney, Brett S; Weber, Darren; Lönnerdal, Bo

2017-02-01

Human milk is the optimal mode of infant feeding for the first several months of life, and infant formulas serve as an alternative when breast-feeding is not possible. Milk proteins have a balanced amino acid composition and some of them provide beneficial bioactivities in their intact forms. They also encrypt a variety of bioactive peptides, possibly contributing to infant health and growth. However, there is limited knowledge of how milk proteins are digested in the gastrointestinal tract and bioactive peptides are released in infants. A peptidomic analysis was conducted to identify peptides released from milk proteins in human milk and infant formula, using a suckling rat pup model. Among the major milk proteins targeted, α-lactalbumin and β-casein in human milk, and β-lactoglobulin and β-casein in infant formula were the main sources of peptides, and these peptides covered large parts of the parental proteins' sequences. Release of peptides was concentrated to specific regions, such as residues 70-92 of β-casein in human milk, residues 39-55 of β-lactoglobulin in infant formula, and residues 57-96 and 145-161 of β-CN in infant formula, where resistance to gastrointestinal digestion was suggested. In the context of bioactive peptides, release of fragments containing known bioactive peptides was confirmed, such as β-CN-derived opioid and antihypertensive peptides. It is therefore likely that these fragments are of biological significance in neonatal health and development. Copyright © 2016 Elsevier Inc. All rights reserved.

Variability of hydrolysis of β-, αs1-, and αs2-caseins by 10 strains of Streptococcus thermophilus and resulting bioactive peptides.

PubMed

Miclo, Laurent; Roux, Emeline; Genay, Magali; Brusseaux, Emilie; Poirson, Chantal; Jameh, Nawara; Perrin, Clarisse; Dary, Annie

2012-01-18

Milk proteins contain numerous potential bioactive peptides, which may be released by digestive proteases or by the proteolytic system of lactic acid bacteria during food processing. The capacity of Streptococcus thermophilus to generate peptides, especially bioactive peptides, from bovine caseins was investigated. Strains expressing various levels of the cell envelope proteinase, PrtS, were incubated with α(s1)-, α(s2)-, or β-casein. Analysis of the supernatants by LC-ESI-MS/MS showed that the β-casein was preferentially hydrolyzed, followed by α(s2)-casein and then α(s1)-casein. Numbers and types of peptides released were strain-dependent. Hydrolysis appeared to be linked with the accessibility of different casein regions by protease. Analysis of bonds hydrolyzed in the region 1-23 of α(s1)-casein suggests that PrtS is at least in part responsible for the peptide production. Finally, among the generated peptides, 13 peptides from β-casein, 5 from α(s2)-casein, and 2 from α(s1)-casein have been reported as bioactive, 15 of them being angiotensin-converting enzyme inhibitors.

Food-derived bioactive peptides on inflammation and oxidative stress.

PubMed

Chakrabarti, Subhadeep; Jahandideh, Forough; Wu, Jianping

2014-01-01

Chronic diseases such as atherosclerosis and cancer are now the leading causes of morbidity and mortality worldwide. Inflammatory processes and oxidative stress underlie the pathogenesis of these pathological conditions. Bioactive peptides derived from food proteins have been evaluated for various beneficial effects, including anti-inflammatory and antioxidant properties. In this review, we summarize the roles of various food-derived bioactive peptides in inflammation and oxidative stress and discuss the potential benefits and limitations of using these compounds against the burden of chronic diseases.

Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome

PubMed Central

Müller, Christina A.; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C. A.; Wellington, Elizabeth M. H.

2015-01-01

Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. PMID:26002894

Revealing the first uridyl peptide antibiotic biosynthetic gene cluster and probing pacidamycin biosynthesis.

PubMed

Rackham, Emma J; Grüschow, Sabine; Goss, Rebecca J M

2011-01-01

There is an urgent need for new antibiotics with resistance continuing to emerge toward existing classes. The pacidamycin antibiotics possess a novel scaffold and exhibit unexploited bioactivity rendering them attractive research targets. We recently reported the first identification of a biosynthetic cluster encoding uridyl peptide antibiotic assembly and the engineering of pacidamycin biosynthesis into a heterologous host. We report here our methods toward identifying the biosynthetic cluster. Our initial experiments employed conventional methods of probing a cosmid library using PCR and Southern blotting, however it became necessary to adopt a state-of-the-art genome scanning  and in silico hybridization approach  to pin point the cluster. Here we describe our "real" and "virtual" probing methods and contrast the benefits and pitfalls of each approach. 

Food-derived immunomodulatory peptides.

PubMed

Santiago-López, Lourdes; Hernández-Mendoza, Adrián; Vallejo-Cordoba, Belinda; Mata-Haro, Verónica; González-Córdova, Aarón F

2016-08-01

Food proteins contain specific amino acid sequences within their structures that may positively impact bodily functions and have multiple immunomodulatory effects. The functional properties of these specific sequences, also referred to as bioactive peptides, are revealed only after the degradation of native proteins during digestion processes. Currently, milk proteins have been the most explored source of bioactive peptides, which presents an interesting opportunity for the dairy industry. However, plant- and animal-derived proteins have also been shown to be important sources of bioactive peptides. This review summarizes the in vitro and in vivo evidence of the role of various food proteins as sources of immunomodulatory peptides and discusses the possible pathways involving these properties. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Characterization of GdFFD, a d-Amino Acid-containing Neuropeptide That Functions as an Extrinsic Modulator of the Aplysia Feeding Circuit*

PubMed Central

Bai, Lu; Livnat, Itamar; Romanova, Elena V.; Alexeeva, Vera; Yau, Peter M.; Vilim, Ferdinand S.; Weiss, Klaudiusz R.; Jing, Jian; Sweedler, Jonathan V.

2013-01-01

During eukaryotic translation, peptides/proteins are created using l-amino acids. However, a d-amino acid-containing peptide (DAACP) can be produced through post-translational modification via an isomerase enzyme. General approaches to identify novel DAACPs and investigate their function, particularly in specific neural circuits, are lacking. This is primarily due to the difficulty in characterizing this modification and due to the limited information on neural circuits in most species. We describe a multipronged approach to overcome these limitations using the sea slug Aplysia californica. Based on bioinformatics and homology to known DAACPs in the land snail Achatina fulica, we targeted two predicted peptides in Aplysia, GFFD, similar to achatin-I (GdFAD versus GFAD, where dF stands for d-phenylalanine), and YAEFLa, identical to fulyal (YdAEFLa versus YAEFLa), using stereoselective analytical methods, i.e. MALDI MS fragmentation analysis and LC-MS/MS. Although YAEFLa in Aplysia was detected only in an all l-form, we found that both GFFD and GdFFD were present in the Aplysia CNS. In situ hybridization and immunolabeling of GFFD/GdFFD-positive neurons and fibers suggested that GFFD/GdFFD might act as an extrinsic modulator of the feeding circuit. Consistent with this hypothesis, we found that GdFFD induced robust activity in the feeding circuit and elicited egestive motor patterns. In contrast, the peptide consisting of all l-amino acids, GFFD, was not bioactive. Our data indicate that the modification of an l-amino acid-containing neuropeptide to a DAACP is essential for peptide bioactivity in a motor circuit, and thus it provides a functional significance to this modification. PMID:24078634

Cell attachment functionality of bioactive conducting polymers for neural interfaces.

PubMed

Green, Rylie A; Lovell, Nigel H; Poole-Warren, Laura A

2009-08-01

Bioactive coatings for neural electrodes that are tailored for cell interactions have the potential to produce superior implants with improved charge transfer capabilities. In this study synthetically produced anionically modified laminin peptides DEDEDYFQRYLI and DCDPGYIGSR were used to dope poly(3,4-ethylenedioxythiophene) (PEDOT) electrodeposited on platinum (Pt) electrodes. Performance of peptide doped films was compared to conventional polymer PEDOT/paratoluene sulfonate (pTS) films using SEM, XPS, cyclic voltammetry, impedance spectroscopy, mechanical hardness and adherence. Bioactivity of incorporated peptides and their affect on cell growth was assessed using a PC12 neurite outgrowth assay. It was demonstrated that large peptide dopants produced softer PEDOT films with a minimal decrease in electrochemical stability, compared to the conventional dopant, pTS. Cell studies revealed that the YFQRYLI ligand retained neurite outgrowth bioactivity when DEDEDYFQRYLI was used as a dopant, but the effect was strongly dependant on initial cell attachment. Alternate peptide dopant, DCDPGYIGSR was found to impart superior cell attachment properties when compared to DEDEDYFQRYLI, but attachment on both peptide doped polymers could be enhanced by coating with whole native laminin.

Human gut endogenous proteins as a potential source of angiotensin-I-converting enzyme (ACE-I)-, renin inhibitory and antioxidant peptides.

PubMed

Dave, Lakshmi A; Hayes, Maria; Montoya, Carlos A; Rutherfurd, Shane M; Moughan, Paul J

2016-02-01

It is well known that endogenous bioactive proteins and peptides play a substantial role in the body's first line of immunological defence, immune-regulation and normal body functioning. Further, the peptides derived from the luminal digestion of proteins are also important for body function. For example, within the peptide database BIOPEP (http://www.uwm.edu.pl/biochemia/index.php/en/biopep) 12 endogenous antimicrobial and 64 angiotensin-I-converting enzyme (ACE-I) inhibitory peptides derived from human milk and plasma proteins are listed. The antimicrobial peptide database (http://aps.unmc.edu/AP/main.php) lists over 111 human host-defence peptides. Several endogenous proteins are secreted in the gut and are subject to the same gastrointestinal digestion processes as food proteins derived from the diet. The human gut endogenous proteins (GEP) include mucins, serum albumin, digestive enzymes, hormones, and proteins from sloughed off epithelial cells and gut microbiota, and numerous other secreted proteins. To date, much work has been carried out regarding the health altering effects of food-derived bioactive peptides but little attention has been paid to the possibility that GEP may also be a source of bioactive peptides. In this review, we discuss the potential of GEP to constitute a gut cryptome from which bioactive peptides such as ACE-I inhibitory, renin inhibitory and antioxidant peptides may be derived. Copyright © 2015 Elsevier Inc. All rights reserved.

Emerging concepts promising new horizons for marine biodiscovery and synthetic biology.

PubMed

Reen, F Jerry; Gutiérrez-Barranquero, José A; Dobson, Alan D W; Adams, Claire; O'Gara, Fergal

2015-05-13

The vast oceans of the world, which comprise a huge variety of unique ecosystems, are emerging as a rich and relatively untapped source of novel bioactive compounds with invaluable biotechnological and pharmaceutical potential. Evidence accumulated over the last decade has revealed that the diversity of marine microorganisms is enormous with many thousands of bacterial species detected that were previously unknown. Associated with this diversity is the production of diverse repertoires of bioactive compounds ranging from peptides and enzymes to more complex secondary metabolites that have significant bioactivity and thus the potential to be exploited for innovative biotechnology. Here we review the discovery and functional potential of marine bioactive peptides such as lantibiotics, nanoantibiotics and peptidomimetics, which have received particular attention in recent years in light of their broad spectrum of bioactivity. The significance of marine peptides in cell-to-cell communication and how this may be exploited in the discovery of novel bioactivity is also explored. Finally, with the recent advances in bioinformatics and synthetic biology, it is becoming clear that the integration of these disciplines with genetic and biochemical characterization of the novel marine peptides, offers the most potential in the development of the next generation of societal solutions.

Emerging Concepts Promising New Horizons for Marine Biodiscovery and Synthetic Biology

PubMed Central

Reen, F. Jerry; Gutiérrez-Barranquero, José A.; Dobson, Alan D. W.; Adams, Claire; O’Gara, Fergal

2015-01-01

The vast oceans of the world, which comprise a huge variety of unique ecosystems, are emerging as a rich and relatively untapped source of novel bioactive compounds with invaluable biotechnological and pharmaceutical potential. Evidence accumulated over the last decade has revealed that the diversity of marine microorganisms is enormous with many thousands of bacterial species detected that were previously unknown. Associated with this diversity is the production of diverse repertoires of bioactive compounds ranging from peptides and enzymes to more complex secondary metabolites that have significant bioactivity and thus the potential to be exploited for innovative biotechnology. Here we review the discovery and functional potential of marine bioactive peptides such as lantibiotics, nanoantibiotics and peptidomimetics, which have received particular attention in recent years in light of their broad spectrum of bioactivity. The significance of marine peptides in cell-to-cell communication and how this may be exploited in the discovery of novel bioactivity is also explored. Finally, with the recent advances in bioinformatics and synthetic biology, it is becoming clear that the integration of these disciplines with genetic and biochemical characterization of the novel marine peptides, offers the most potential in the development of the next generation of societal solutions. PMID:25984990

Bio-active molecules modified surfaces enhanced mesenchymal stem cell adhesion and proliferation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mobasseri, Rezvan; Center for Nanofibers & Nanotechnology, Department of Mechanical Engineering, National University of Singapore, 117576; Tian, Lingling

Surface modification of the substrate as a component of in vitro cell culture and tissue engineering, using bio-active molecules including extracellular matrix (ECM) proteins or peptides derived ECM proteins can modulate the surface properties and thereby induce the desired signaling pathways in cells. The aim of this study was to evaluate the behavior of human bone marrow mesenchymal stem cells (hBM-MSCs) on glass substrates modified with fibronectin (Fn), collagen (Coll), RGD peptides (RGD) and designed peptide (R-pept) as bio-active molecules. The glass coverslips were coated with fibronectin, collagen, RGD peptide and R-peptide. Bone marrow mesenchymal stem cells were cultured on differentmore » substrates and the adhesion behavior in early incubation times was investigated using scanning electron microscopy (SEM) and confocal microscopy. The MTT assay was performed to evaluate the effect of different bio-active molecules on MSCs proliferation rate during 24 and 72 h. Formation of filopodia and focal adhesion (FA) complexes, two steps of cell adhesion process, were observed in MSCs cultured on bio-active molecules modified coverslips, specifically in Fn coated and R-pept coated groups. SEM image showed well adhesion pattern for MSCs cultured on Fn and R-pept after 2 h incubation, while the shape of cells cultured on Coll and RGD substrates indicated that they might experience stress condition in early hours of culture. Investigation of adhesion behavior, as well as proliferation pattern, suggests R-peptide as a promising bio-active molecule to be used for surface modification of substrate in supporting and inducing cell adhesion and proliferation. - Highlights: • Bioactive molecules modified surface is a strategy to design biomimicry scaffold. • Bi-functional Tat-derived peptide (R-pept) enhanced MSCs adhesion and proliferation. • R-pept showed similar influences to fibronectin on FA formation and attachment.« less

Marine Peptides: Bioactivities and Applications

PubMed Central

Cheung, Randy Chi Fai; Ng, Tzi Bun; Wong, Jack Ho

2015-01-01

Peptides are important bioactive natural products which are present in many marine species. These marine peptides have high potential nutraceutical and medicinal values because of their broad spectra of bioactivities. Their antimicrobial, antiviral, antitumor, antioxidative, cardioprotective (antihypertensive, antiatherosclerotic and anticoagulant), immunomodulatory, analgesic, anxiolytic anti-diabetic, appetite suppressing and neuroprotective activities have attracted the attention of the pharmaceutical industry, which attempts to design them for use in the treatment or prevention of various diseases. Some marine peptides or their derivatives have high commercial values and had reached the pharmaceutical and nutraceutical markets. A large number of them are already in different phases of the clinical and preclinical pipeline. This review highlights the recent research in marine peptides and the trends and prospects for the future, with special emphasis on nutraceutical and pharmaceutical development into marketed products. PMID:26132844

In vitro and direct in vivo testing of mixture-based combinatorial libraries for the identification of highly active and specific opiate ligands.

PubMed

Houghten, Richard A; Dooley, Colette T; Appel, Jon R

2006-05-26

The use of combinatorial libraries for the identification of novel opiate and related ligands in opioid receptor assays is reviewed. Case studies involving opioid assays used to demonstrate the viability of combinatorial libraries are described. The identification of new opioid peptides composed of L-amino acids, D-amino acids, or L-, D-, and unnatural amino acids is reviewed. New opioid compounds have also been identified from peptidomimetic libraries, such as peptoids and alkylated dipeptides, and those identified from acyclic (eg, polyamine, urea) and heterocyclic (eg, bicyclic guanidine) libraries are reviewed.

Bioactive and Biodegradable Nanocomposites and Hybrid Biomaterials for Bone Regeneration

PubMed Central

Allo, Bedilu A.; Costa, Daniel O.; Dixon, S. Jeffrey; Mequanint, Kibret; Rizkalla, Amin S.

2012-01-01

Strategies for bone tissue engineering and regeneration rely on bioactive scaffolds to mimic the natural extracellular matrix and act as templates onto which cells attach, multiply, migrate and function. Of particular interest are nanocomposites and organic-inorganic (O/I) hybrid biomaterials based on selective combinations of biodegradable polymers and bioactive inorganic materials. In this paper, we review the current state of bioactive and biodegradable nanocomposite and O/I hybrid biomaterials and their applications in bone regeneration. We focus specifically on nanocomposites based on nano-sized hydroxyapatite (HA) and bioactive glass (BG) fillers in combination with biodegradable polyesters and their hybrid counterparts. Topics include 3D scaffold design, materials that are widely used in bone regeneration, and recent trends in next generation biomaterials. We conclude with a perspective on the future application of nanocomposites and O/I hybrid biomaterials for regeneration of bone. PMID:24955542

Marine natural product peptides with therapeutic potential: Chemistry, biosynthesis, and pharmacology.

PubMed

Gogineni, Vedanjali; Hamann, Mark T

2018-01-01

The oceans are a uniquely rich source of bioactive metabolites, of which sponges have been shown to be among the most prolific producers of diverse bioactive secondary metabolites with valuable therapeutic potential. Much attention has been focused on marine bioactive peptides due to their novel chemistry and diverse biological properties. As summarized in this review, marine peptides are known to exhibit various biological activities such as antiviral, anti-proliferative, antioxidant, anti-coagulant, anti-hypertensive, anti-cancer, antidiabetic, antiobesity, and calcium-binding activities. This review focuses on the chemistry and biology of peptides isolated from sponges, bacteria, cyanobacteria, fungi, ascidians, and other marine sources. The role of marine invertebrate microbiomes in natural products biosynthesis is discussed in this review along with the biosynthesis of modified peptides from different marine sources. The status of peptides in various phases of clinical trials is presented, as well as the development of modified peptides including optimization of PK and bioavailability. Copyright © 2017 Elsevier B.V. All rights reserved.

Impact of commercial precooking of common bean (Phaseolus vulgaris) on the generation of peptides, after pepsin-pancreatin hydrolysis, capable to inhibit dipeptidyl peptidase-IV.

PubMed

Mojica, Luis; Chen, Karen; de Mejía, Elvira González

2015-01-01

The objective of this research was to determine the bioactive properties of the released peptides from commercially available precook common beans (Phaseolus vulgaris). Bioactive properties and peptide profiles were evaluated in protein hydrolysates of raw and commercially precooked common beans. Five varieties (Black, Pinto, Red, Navy, and Great Northern) were selected for protein extraction, protein and peptide molecular mass profiles, and peptide sequences. Potential bioactivities of hydrolysates, including antioxidant capacity and inhibition of α-amylase, α-glucosidase, dipeptidyl peptidase-IV (DPP-IV), and angiotensin converting enzyme I (ACE) were analyzed after digestion with pepsin/pancreatin. Hydrolysates from Navy beans were the most potent inhibitors of DPP-IV with no statistical differences between precooked and raw (IC50 = 0.093 and 0.095 mg protein/mL, respectively). α-Amylase inhibition was higher for raw Red, Navy and Great Northern beans (36%, 31%, 27% relative to acarbose (rel ac)/mg protein, respectively). α-Glucosidase inhibition among all bean hydrolysates did not show significant differences; however, inhibition values were above 40% rel ac/mg protein. IC50 values for ACE were not significantly different among all bean hydrolysates (range 0.20 to 0.34 mg protein/mL), except for Red bean that presented higher IC50 values. Peptide molecular mass profile ranged from 500 to 3000 Da. A total of 11 and 17 biologically active peptide sequences were identified in raw and precooked beans, respectively. Peptide sequences YAGGS and YAAGS from raw Great Northern and precooked Pinto showed similar amino acid sequences and same potential ACE inhibition activity. Processing did not affect the bioactive properties of released peptides from precooked beans. Commercially precooked beans could contribute to the intake of bioactive peptides and promote health. © 2014 Institute of Food Technologists®

Identification and Characterization of Bioactive Peptides of Fermented Goat Milk as a Sources of Antioxidant as a Therapeutic Natural Product

NASA Astrophysics Data System (ADS)

Mahdi, Chanif; Untari, Handayu; Cendrakasih Padaga, Masdiana

2018-01-01

The increasing of functional food is rising in line with public awareness for healthy food consumption. Provision of functional food source is developed through enhanced bioactive that has a regulatory function for body. Bioactive peptides in milk is known have variety of beneficial function of the body such as immunomodulator, immunostimulatory, anti-hypertension, anti-hyper cholesterol, as well as a variety of other beneficial function. The aim of this study is to obtain fermentation methods to product functional dairy product contain bioactive peptides and beneficial of fermented goat milk. The result of this study showed that goat milk fermented using 3 % commercial starter able to produce the best yoghurt than using local yoghurt starter. Analysis of protein content showed that the fermentation processing increased the amount of protein in goat milk sample. Using SDS-PAGE showed that the breakdown of protein into fraction of fermented goat milk greater than unfermented goat milk. The result of fractional protein was analyzed by LC MS/MS and showed that there were three kind bioactive sequences of bioactive peptides. Each of which consist of 16 amino acids that safely protected from gastrointestinal animal model that fed by dietary treatment of hypercholesterolemia.

Bioactive compounds in dairy products and their relation to neurodegenerative disease

USDA-ARS?s Scientific Manuscript database

Enhancement of nervous system function and cognitive ability may be aided by bioactive compounds found in dairy products, including calcium-binding phosphopeptides and peptides derived from casein and beta-lactoglobulin. These peptides inhibit angiotensin converting enzyme I, scavenge radicals, red...

Mining for Nonribosomal Peptide Synthetase and Polyketide Synthase Genes Revealed a High Level of Diversity in the Sphagnum Bog Metagenome.

PubMed

Müller, Christina A; Oberauner-Wappis, Lisa; Peyman, Armin; Amos, Gregory C A; Wellington, Elizabeth M H; Berg, Gabriele

2015-08-01

Sphagnum bog ecosystems are among the oldest vegetation forms harboring a specific microbial community and are known to produce an exceptionally wide variety of bioactive substances. Although the Sphagnum metagenome shows a rich secondary metabolism, the genes have not yet been explored. To analyze nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs), the diversity of NRPS and PKS genes in Sphagnum-associated metagenomes was investigated by in silico data mining and sequence-based screening (PCR amplification of 9,500 fosmid clones). The in silico Illumina-based metagenomic approach resulted in the identification of 279 NRPSs and 346 PKSs, as well as 40 PKS-NRPS hybrid gene sequences. The occurrence of NRPS sequences was strongly dominated by the members of the Protebacteria phylum, especially by species of the Burkholderia genus, while PKS sequences were mainly affiliated with Actinobacteria. Thirteen novel NRPS-related sequences were identified by PCR amplification screening, displaying amino acid identities of 48% to 91% to annotated sequences of members of the phyla Proteobacteria, Actinobacteria, and Cyanobacteria. Some of the identified metagenomic clones showed the closest similarity to peptide synthases from Burkholderia or Lysobacter, which are emerging bacterial sources of as-yet-undescribed bioactive metabolites. This report highlights the role of the extreme natural ecosystems as a promising source for detection of secondary compounds and enzymes, serving as a source for biotechnological applications. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Seaweed as a source of novel nutraceuticals: sulfated polysaccharides and peptides.

PubMed

Jiménez-Escrig, A; Gómez-Ordóñez, E; Rupérez, P

2011-01-01

Seaweeds and seaweed-derived products are underexploited marine bioresources and a source of natural ingredients for functional foods. Nutritional studies on seaweeds indicate that brown and red seaweeds possess a good nutritional quality and could be used as an alternative source of dietary fiber, protein, and minerals. Moreover, bioactive sulfated polysaccharides are the main components of soluble fiber in seaweeds and also bioactive peptides can be prepared from seaweed protein. This chapter gives an overview of the main biological properties of sulfated polysaccharides and peptides from brown and red seaweeds. Recent studies have provided evidence that sulfated polysaccharides from seaweeds can play a vital role in human health and nutrition. Besides, peptides derived from algal protein are most promising as antihypertensive agents. Further research work, especially in vivo studies, are needed in order to gain a better knowledge of the relation structure-function by which bioactive compounds from seaweeds exert their bioactivity. Copyright © 2011 Elsevier Inc. All rights reserved.

Marine Peptides and Their Anti-Infective Activities

PubMed Central

Kang, Hee Kyoung; Seo, Chang Ho; Park, Yoonkyung

2015-01-01

Marine bioresources are a valuable source of bioactive compounds with industrial and nutraceutical potential. Numerous clinical trials evaluating novel chemotherapeutic agents derived from marine sources have revealed novel mechanisms of action. Recently, marine-derived bioactive peptides have attracted attention owing to their numerous beneficial effects. Moreover, several studies have reported that marine peptides exhibit various anti-infective activities, such as antimicrobial, antifungal, antimalarial, antiprotozoal, anti-tuberculosis, and antiviral activities. In the last several decades, studies of marine plants, animals, and microbes have revealed tremendous number of structurally diverse and bioactive secondary metabolites. However, the treatments available for many infectious diseases caused by bacteria, fungi, and viruses are limited. Thus, the identification of novel antimicrobial peptides should be continued, and all possible strategies should be explored. In this review, we will present the structures and anti-infective activity of peptides isolated from marine sources (sponges, algae, bacteria, fungi and fish) from 2006 to the present. PMID:25603351

The degradation of bioactive peptides and proteins by dipeptidyl peptidase IV from human placenta.

PubMed

Nausch, I; Mentlein, R; Heymann, E

1990-11-01

The degradation of several bioactive peptides and proteins by purified human dipeptidyl peptidase IV is reported. It was hitherto unknown that human gastrin-releasing peptide, human chorionic gonadotropin, human pancreatic polypeptide, sheep prolactin, aprotinin, corticotropin-like intermediate lobe peptide and (Tyr-)melanostatin are substrates of this peptidase. Kinetic constants were determined for the degradation of a number of other natural peptides, including substance P, the degradation of which has been described earlier in a qualitative manner. Generally, small peptides are degraded much more rapidly than proteins. However, the Km-values seem to be independent of the peptide chain length. The influence of the action of dipeptidyl peptidase IV on the biological function of peptides and proteins is discussed.

Evidence for cis Amide Bonds in Peptoid Nanosheets.

PubMed

Hudson, Benjamin C; Battigelli, Alessia; Connolly, Michael D; Edison, John; Spencer, Ryan K; Whitelam, Stephen; Zuckermann, Ronald N; Paravastu, Anant K

2018-05-17

Peptoid nanosheets are supramolecular protein-mimetic materials that form from amphiphilic polypeptoids with aromatic and ionic side chains. Nanosheets have been studied at the nanometer scale, but the molecular structure has been difficult to probe. We report the use of 13 C- 13 C dipolar recoupling solid-state NMR measurements to reveal the configuration of backbone amide bonds selected by 13 C isotopic labeling of adjacent α-carbons. Measurements on the same molecules in the amorphous state and in nanosheets revealed that amide bonds in the center of the amino block of peptoid (NaeNpe) 7 -(NceNpe) 7 (B28) favor the trans configuration in the amorphous state and the cis configuration in the nanosheet. This unexpected result contrasts with previous NMR and theoretical studies of short solvated peptoids. Furthermore, examination of the amide bond at the junction of the two charged blocks within B28 revealed a mixture of both cis and trans configurational states, consistent with the previously predicted brickwork-like intermolecular organization.

A bioactive coating of a silica xerogel/chitosan hybrid on titanium by a room temperature sol-gel process.

PubMed

Jun, Shin-Hee; Lee, Eun-Jung; Yook, Se-Won; Kim, Hyoun-Ee; Kim, Hae-Won; Koh, Young-Hag

2010-01-01

A bioactive coating consisting of a silica xerogel/chitosan hybrid was applied to Ti at room temperature as a novel surface treatment for metallic implants. A crack-free thin layer (<2 microm) was coated on Ti with a chitosan content of >30 vol.% through a sol-gel process. The coating layer became more hydrophilic with increasing silica xerogel content, as assessed by contact angle measurement. The hybrid coatings afforded excellent bone bioactivity by inducing the rapid precipitation of apatite on their surface when immersed in a simulated body fluid (SBF). Osteoblastic cells cultured on the hybrid coatings were more viable than those on a pure chitosan coating. Furthermore, the alkaline phosphate activity of the cells was significantly higher on the hybrid coatings than on a pure chitosan coating, with the highest level being achieved on the hybrid coating containing 30% chitosan. These results indicate that silica xerogel/chitosan hybrids are potentially useful as room temperature bioactive coating materials on titanium-based medical implants.

Effect of probiotics on antioxidant and antimutagenic activities of crude peptide extract from yogurt.

PubMed

Sah, B N P; Vasiljevic, T; McKechnie, S; Donkor, O N

2014-08-01

Search for bioactive peptides is intensifying because of the risks associated with the use of synthetic therapeutics, thus peptide liberation by lactic acid bacteria and probiotics has received a great focus. However, proteolytic capacity of these bacteria is strain specific. The study was conducted to establish proteolytic activity of Lactobacillus acidophilus (ATCC® 4356™), Lactobacillus casei (ATCC® 393™) and Lactobacillus paracasei subsp. paracasei (ATCC® BAA52™) in yogurt. Crude peptides were separated by high-speed centrifugation and tested for antioxidant and antimutagenic activities. The degree of proteolysis highly correlated with these bioactivities, and its value (11.91%) for samples containing all the cultures was double that of the control. Liberated peptides showed high radical scavenging activities with 1,1-diphenyl-2-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), IC50 1.51 and 1.63mg/ml, respectively and strong antimutagenicity (26.35%). These probiotics enhanced the generation of bioactive peptides and could possibly be commercially applied in new products, or production of novel anticancer peptides. Crown Copyright © 2014. Published by Elsevier Ltd. All rights reserved.

Marine Fish Proteins and Peptides for Cosmeceuticals: A Review

PubMed Central

Venkatesan, Jayachandran; Anil, Sukumaran; Kim, Se-Kwon; Shim, Min Suk

2017-01-01

Marine fish provide a rich source of bioactive compounds such as proteins and peptides. The bioactive proteins and peptides derived from marine fish have gained enormous interest in nutraceutical, pharmaceutical, and cosmeceutical industries due to their broad spectrum of bioactivities, including antioxidant, antimicrobial, and anti-aging activities. Recently, the development of cosmeceuticals using marine fish-derived proteins and peptides obtained from chemical or enzymatical hydrolysis of fish processing by-products has increased rapidly owing to their activities in antioxidation and tissue regeneration. Marine fish-derived collagen has been utilized for the development of cosmeceutical products due to its abilities in skin repair and tissue regeneration. Marine fish-derived peptides have also been utilized for various cosmeceutical applications due to their antioxidant, antimicrobial, and matrix metalloproteinase inhibitory activities. In addition, marine fish-derived proteins and hydrolysates demonstrated efficient anti-photoaging activity. The present review highlights and presents an overview of the current status of the isolation and applications of marine fish-derived proteins and peptides. This review also demonstrates that marine fish-derived proteins and peptides have high potential for biocompatible and effective cosmeceuticals. PMID:28524092

Enzymatic Hydrolysis of Peanut Flour Produces Bioactive Peptides with Reduced Allergenicity

USDA-ARS?s Scientific Manuscript database

Peanut allergy is one of the most severe food allergies due to its life-threatening nature and persistency. Current immunotherapy methods, though effective, are often accompanied by allergic side-effects. Enzymatic hydrolysis of peanut flour has the potential to produce bioactive peptides with impro...

2D nanomaterials assembled from sequence-defined molecules

DOE PAGES

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

2017-10-21

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

Blood biomarker for Parkinson disease: peptoids

PubMed Central

Yazdani, Umar; Zaman, Sayed; Hynan, Linda S; Brown, L Steven; Dewey, Richard B; Karp, David; German, Dwight C

2016-01-01

Parkinson disease (PD) is the second most common neurodegenerative disease. Because dopaminergic neuronal loss begins years before motor symptoms appear, a biomarker for the early identification of the disease is critical for the study of putative neuroprotective therapies. Brain imaging of the nigrostriatal dopamine system has been used as a biomarker for early disease along with cerebrospinal fluid analysis of α-synuclein, but a less costly and relatively non-invasive biomarker would be optimal. We sought to identify an antibody biomarker in the blood of PD patients using a combinatorial peptoid library approach. We examined serum samples from 75 PD patients, 25 de novo PD patients, and 104 normal control subjects in the NINDS Parkinson’s Disease Biomarker Program. We identified a peptoid, PD2, which binds significantly higher levels of IgG3 antibody in PD versus control subjects (P<0.0001) and is 68% accurate in identifying PD. The PD2 peptoid is 84% accurate in identifying de novo PD. Also, IgG3 levels are significantly higher in PD versus control serum (P<0.001). Finally, PD2 levels are positively correlated with the United Parkinson’s Disease Rating Scale score (r=0.457, P<0001), a marker of disease severity. The PD2 peptoid may be useful for the early-stage identification of PD, and serve as an indicator of disease severity. Additional studies are needed to validate this PD biomarker. PMID:27812535

Bioactive Peptides Derived from Seaweed Protein and Their Health Benefits: Antihypertensive, Antioxidant, and Antidiabetic Properties.

PubMed

Admassu, Habtamu; Gasmalla, Mohammed Abdalbasit A; Yang, Ruijin; Zhao, Wei

2018-01-01

Cardiovascular diseases and diabetes are the biggest causes of death globally. Therefore, prevention of these diseases is a focus of pharmaceuticals and functional food manufacturers. This review summarizes recent research trends and scientific knowledge in seaweed protein-derived peptides with particular emphasis on production, isolation and potential health impacts in prevention of hypertension, diabetes and oxidative stress. The current status and future prospects of bioactive peptides are also discussed. Bioactive peptides have strong potential for use in therapeutic drug and functional food formulation in health management strategy, especially cardiovascular disease and diabetes. Seaweeds can be used as sustainable protein sources in the production of these peptide-based drugs and functional foods for preventing such diseases. Many studies have reported that peptides showing angiotensin converting enzyme inhibition, antihypertensive, antioxidative and antidiabetics activities, have been successfully isolated from seaweed. However, further research is needed in large-scale production of these peptides, efficient isolation methods, interactions with functional foods and other pharmaceuticals, and their ease to digestion in in vivo studies and safety to validate the health benefits of these peptides. © 2017 Institute of Food Technologists®.

Co-assembly, spatiotemporal control and morphogenesis of a hybrid protein-peptide system.

PubMed

Inostroza-Brito, Karla E; Collin, Estelle; Siton-Mendelson, Orit; Smith, Katherine H; Monge-Marcet, Amàlia; Ferreira, Daniela S; Rodríguez, Raúl Pérez; Alonso, Matilde; Rodríguez-Cabello, José Carlos; Reis, Rui L; Sagués, Francesc; Botto, Lorenzo; Bitton, Ronit; Azevedo, Helena S; Mata, Alvaro

2015-11-01

Controlling molecular interactions between bioinspired molecules can enable the development of new materials with higher complexity and innovative properties. Here we report on a dynamic system that emerges from the conformational modification of an elastin-like protein by peptide amphiphiles and with the capacity to access, and be maintained in, non-equilibrium for substantial periods of time. The system enables the formation of a robust membrane that displays controlled assembly and disassembly capabilities, adhesion and sealing to surfaces, self-healing and the capability to undergo morphogenesis into tubular structures with high spatiotemporal control. We use advanced microscopy along with turbidity and spectroscopic measurements to investigate the mechanism of assembly and its relation to the distinctive membrane architecture and the resulting dynamic properties. Using cell-culture experiments with endothelial and adipose-derived stem cells, we demonstrate the potential of this system to generate complex bioactive scaffolds for applications such as tissue engineering.

Co-assembly, spatiotemporal control and morphogenesis of a hybrid protein-peptide system

NASA Astrophysics Data System (ADS)

Inostroza-Brito, Karla E.; Collin, Estelle; Siton-Mendelson, Orit; Smith, Katherine H.; Monge-Marcet, Amàlia; Ferreira, Daniela S.; Rodríguez, Raúl Pérez; Alonso, Matilde; Rodríguez-Cabello, José Carlos; Reis, Rui L.; Sagués, Francesc; Botto, Lorenzo; Bitton, Ronit; Azevedo, Helena S.; Mata, Alvaro

2015-11-01

Controlling molecular interactions between bioinspired molecules can enable the development of new materials with higher complexity and innovative properties. Here we report on a dynamic system that emerges from the conformational modification of an elastin-like protein by peptide amphiphiles and with the capacity to access, and be maintained in, non-equilibrium for substantial periods of time. The system enables the formation of a robust membrane that displays controlled assembly and disassembly capabilities, adhesion and sealing to surfaces, self-healing and the capability to undergo morphogenesis into tubular structures with high spatiotemporal control. We use advanced microscopy along with turbidity and spectroscopic measurements to investigate the mechanism of assembly and its relation to the distinctive membrane architecture and the resulting dynamic properties. Using cell-culture experiments with endothelial and adipose-derived stem cells, we demonstrate the potential of this system to generate complex bioactive scaffolds for applications such as tissue engineering.

Cadherin juxtamembrane region derived peptides inhibit TGFβ1 induced gene expression

PubMed Central

Stavropoulos, Ilias; Golla, Kalyan; Moran, Niamh; Martin, Finian; Shields, Denis C

2014-01-01

Bioactive peptides in the juxtamembrane regions of proteins are involved in many signaling events. The juxtamembrane regions of cadherins were examined for the identification of bioactive regions. Several peptides spanning the cytoplasmic juxtamembrane regions of E- and N-cadherin were synthesized and assessed for the ability to influence TGFβ responses in epithelial cells at the gene expression and protein levels. Peptides from regions closer to the membrane appeared more potent inhibitors of TGFβ signaling, blocking Smad3 phosphorylation. Thus inhibiting nuclear translocation of phosphorylated Smad complexes and subsequent transcriptional activation of TGFβ signal propagating genes. The peptides demonstrated a peptide-specific potential to inhibit other TGFβ superfamily members, such as BMP4. PMID:25108297

Egg-yolk protein by-product as a source of ACE-inhibitory peptides obtained with using unconventional proteinase from Asian pumpkin (Cucurbita ficifolia).

PubMed

Eckert, Ewelina; Zambrowicz, Aleksandra; Pokora, Marta; Setner, Bartosz; Dąbrowska, Anna; Szołtysik, Marek; Szewczuk, Zbigniew; Polanowski, Antoni; Trziszka, Tadeusz; Chrzanowska, Józefa

2014-10-14

In the present study angiotensin I-converting enzyme (ACE) inhibitory peptides were isolated from egg-yolk protein preparation (YP). Enzymatic hydrolysis conducted using unconventional enzyme from Cucurbita ficifolia (dose: 1000 U/mg of hydrolyzed YP (E/S (w/w)=1:7.52)) was employed to obtain protein hydrolysates. The 4-h hydrolysate exhibited a significant (IC₅₀=482.5 μg/mL) ACE inhibitory activity. Moreover, hydrolysate showed no cytotoxic activity on human and animal cell lines which makes it a very useful multifunctional method for peptide preparation. The compiled isolation procedure (ultrafiltration, size-exclusion chromatography and RP-HPLC) of bioactive peptides from YP hydrolysate resulted in obtaining peptides with the strong ACE inhibitory activity. One homogeneous and three heterogeneous peptide fractions were identified. The peptides were composed of 9-18 amino-acid residues, including mainly arginine and leucine at the N-terminal positions. To confirm the selected bioactive peptide sequences their analogs were chemically synthesized and tested. Peptide LAPSLPGKPKPD showed the strongest ACE inhibitory activity, with IC₅₀ value of 1.97 μmol/L. Peptides with specific biological activity can be used in pharmaceutical, cosmetic or food industries. Because of their potential role as physiological modulators, as well as theirhigh safety profile, they can be used as natural pharmacological compounds or functional food ingredients. The development of biotechnological solutions to obtain peptides with desired biological activity is already in progress. Studies in this area are focused on using unconventional highly specific enzymes and more efficient methods developed to conduct food process technologies. Natural peptides have many advantages. They are mainly toxicologically safe, have wide spectra of therapeutic actions, exhibit less side effects compared to synthetic drugs and are more efficiently absorbed in the intestinal tract. The complexity of operation of large scale technologies and high cost of purification techniques are limiting factors to the commercialization of food-derived bioactive peptides. Research on the isolation of bioactive peptides in order to reduce the processing time and costs is continuously developing. Bioactive peptides can also be released from protein by-products of the food industry, which reduce the substrate expense and production cost as well as provide the added advantage of an efficient waste disposal. Moreover, proteins as precursors of food-derived peptides are well-tolerated by the human body and therefore their application in drug development may reduce costs and duration of toxicological studies during research, development and clinical trials. Copyright © 2014 Elsevier B.V. All rights reserved.

Membrane-Active Epithelial Keratin 6A Fragments (KAMPs) Are Unique Human Antimicrobial Peptides with a Non-αβ Structure

PubMed Central

Lee, Judy T. Y.; Wang, Guangshun; Tam, Yu Tong; Tam, Connie

2016-01-01

Antibiotic resistance is a pressing global health problem that threatens millions of lives each year. Natural antimicrobial peptides and their synthetic derivatives, including peptoids and peptidomimetics, are promising candidates as novel antibiotics. Recently, the C-terminal glycine-rich fragments of human epithelial keratin 6A were found to have bactericidal and cytoprotective activities. Here, we used an improved 2-dimensional NMR method coupled with a new protocol for structural refinement by low temperature simulated annealing to characterize the solution structure of these kerain-derived antimicrobial peptides (KAMPs). Two specific KAMPs in complex with membrane mimicking sodium dodecyl sulfate (SDS) micelles displayed amphipathic conformations with only local bends and turns, and a central 10-residue glycine-rich hydrophobic strip that is central to bactericidal activity. To our knowledge, this is the first report of non-αβ structure for human antimicrobial peptides. Direct observation of Staphylococcus aureus and Pseudomonas aeruginosa by scanning and transmission electron microscopy showed that KAMPs deformed bacterial cell envelopes and induced pore formation. Notably, in competitive binding experiments, KAMPs demonstrated binding affinities to LPS and LTA that did not correlate with their bactericidal activities, suggesting peptide-LPS and peptide-LTA interactions are less important in their mechanisms of action. Moreover, immunoprecipitation of KAMPs-bacterial factor complexes indicated that membrane surface lipoprotein SlyB and intracellular machineries NQR sodium pump and ribosomes are potential molecular targets for the peptides. Results of this study improve our understanding of the bactericidal function of epithelial cytokeratin fragments, and highlight an unexplored class of human antimicrobial peptides, which may serve as non-αβ peptide scaffolds for the design of novel peptide-based antibiotics. PMID:27891122

Novel pentapeptide, PALAL, derived from a bony fish elicits contraction of the muscle in starfish Patiria pectinifera.

PubMed

Go, Hye-Jin; Kim, Chan-Hee; Oh, Hye Young; Park, Nam Gyu

2016-10-01

A bioactive peptide mimicking peptide-signaling molecules has been isolated from the skin extract of fish Channa argus which caused contraction of the apical muscle of a starfish Patiria pectinifera, a deuterostomian invertebrate. The primary structure of the isolated pentapeptide comprises amino acid sequence of H-Pro-Ala-Leu-Ala-Leu-OH (PALAL) with a molecular mass of 483.7 Da. Pharmacological activity of PALAL, dosage ranging from 10 -9 to 10 -5 M, revealed concentration-dependent contraction of the apical muscles of P. pectinifera and Asterias amurensis. However, PALAL was not active on the intestinal smooth muscle of the goldfish Carassius auratus and has presumably other physiological roles in fish skin. Investigation of structure-activity relationship using truncated and substituted analogs of PALAL demonstrated that H-Ala-Leu-Ala-Leu-OH was necessary and should be sufficient to constrict apical muscle of P. pectinifera. Furthermore, the second alanine residue was required to display the activity, and the fifth leucine residue was responsible for its potency. Comparison with PALAL's primary structure with those of other known bioactive peptides from fish and starfish revealed that PALAL does not have any significant homology. Consequently, PALAL is a bioactive peptide that elicits a muscle contraction in starfish, and the isolation of PALAL may lead to develop other bioactive peptides sharing its similar sequence and/or activity. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Cucurbitaceae Seed Protein Hydrolysates as a Potential Source of Bioactive Peptides with Functional Properties

PubMed Central

2017-01-01

Seeds from Cucurbitaceae plants (squashes, pumpkins, melons, etc.) have been used both as protein-rich food ingredients and nutraceutical agents by many indigenous cultures for millennia. However, relatively little is known about the bioactive components (e.g., peptides) of the Cucurbitaceae seed proteins (CSP) and their specific effects on human health. Therefore, this paper aims to provide a comprehensive review of latest research on bioactive and functional properties of CSP isolates and hydrolysates. Enzymatic hydrolysis can introduce a series of changes to the CSP structure and improve its bioactive and functional properties, including the enhanced protein solubility over a wide range of pH values. Small-sized peptides in CSP hydrolysates seem to enhance their bioactive properties but adversely affect their functional properties. Therefore, medium degrees of hydrolysis seem to benefit the overall improvement of bioactive and functional properties of CSP hydrolysates. Among the reported bioactive properties of CSP isolates and hydrolysates, their antioxidant, antihypertensive, and antihyperglycaemic activities stand out. Therefore, they could potentially substitute synthetic antioxidants and drugs which might have adverse secondary effects on human health. CSP isolates and hydrolysates could also be implemented as functional food ingredients, thanks to their favorable amino acid composition and good emulsifying and foaming properties. PMID:29181389

Identification of the bioactive and consensus peptide motif from Momordica charantia insulin receptor-binding protein.

PubMed

Lo, Hsin-Yi; Li, Chia-Cheng; Ho, Tin-Yun; Hsiang, Chien-Yun

2016-08-01

Many food bioactive peptides with diverse functions have been discovered by studying plant proteins. We have previously identified a 68-residue insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia that exhibits hypoglycemic effects in mice via interaction with IR. By in vitro digestion, we found that mcIRBP-19, spanning residues 50-68 of mcIRBP, enhanced the binding of insulin to IR, stimulated the phosphorylation of PDK1 and Akt, induced the expression of glucose transporter 4, and stimulated both the uptake of glucose in cells and the clearance of glucose in diabetic mice. Furthermore, mcIRBP-19 homologs were present in various plants and shared similar β-hairpin structures and IR kinase-activating abilities to mcIRBP-19. In conclusion, our findings suggested that mcIRBP-19 is a blood glucose-lowering bioactive peptide that exhibits IR-binding potentials. Moreover, we newly identified novel IR-binding bioactive peptides in various plants which belonged to different taxonomic families. Copyright © 2016 Elsevier Ltd. All rights reserved.

Silicon-Containing Amino Acids: Synthetic Aspects, Conformational Studies, and Applications to Bioactive Peptides.

PubMed

Rémond, Emmanuelle; Martin, Charlotte; Martinez, Jean; Cavelier, Florine

2016-10-12

Unnatural α-amino acids form a family of essential molecules used for, among other applications, the synthesis of modified peptides, to improve resistance to proteolytic enzyme degradation, and to modulate physico- and biochemical properties of bioactive peptides as well as chiral inducers in asymmetric synthesis. Among them, silicon-containing unnatural amino acids are becoming an interesting new class of building blocks. The replacement of carbon atoms in bioactive substances with silicon is becoming increasingly popular. Peptides containing silyl amino acids hold great promise for maintaining or reinforcing the biological activity of active compounds, while they simultaneously enhance their resistance to enzyme degradation. In addition, the lipophilicity of the silicon atom facilitates their membrane crossing and their bioavailability. Nowadays, the interest of the pharmaceutical industry in peptide- and protein-based therapies is increasing. In this respect, silicon-containing amino acids and peptides are likely to be a significant part of future innovations in this area, and more generally in the area of biomolecules. In this process, commercial availability of silicon-containing amino acids is necessary: new syntheses have been developed, and work in this area is ongoing. This review aims to be a comprehensive and general summary of the different methods used to prepare silicon-containing amino acids and their implications on conformational structures and biological applications when they are incorporated into bioactive molecules.

Designable and dynamic single-walled stiff nanotubes assembled from sequence-defined peptoids

DOE PAGES

Jin, Haibao; Ding, Yan-Huai; Wang, Mingming; ...

2018-01-18

Despite recent advances in assembly of organic nanotubes, conferral of sequence-defined engineering and dynamic response characteristics to the tubules remains a challenge. Here we report a new family of highly-designable and dynamic single-walled nanotubes assembled from sequence-defined peptoids through a unique “rolling-up and closure of nanosheet” mechanism. During the assembly process, amorphous spherical particles of amphiphilic peptoid oligomers (APOs) crystallized to form well-defined nanosheets which were then folded to form single-walled peptoid nanotubes (SW-PNTs). These SW-PNTs undergo a pH-triggered, reversible contraction-expansion motion. By varying the number of hydrophobic residues of APOs, we demonstrate the tuning of PNT wall thickness andmore » diameter, and mechanical properties. AFM-based mechanical measurements indicate that PNTs are highly stiff (Young’s Modulus ~13-17 GPa), comparable to the stiffest known biological materials. We further demonstrate that the precise incorporation of functional groups within PNTs and the application of functional PNTs in water decontamination. We believe these SW-PNTs can provide a robust platform for development of biomimetic materials tailored to specific applications.« less

Designable and dynamic single-walled stiff nanotubes assembled from sequence-defined peptoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Haibao; Ding, Yan-Huai; Wang, Mingming

Despite recent advances in assembly of organic nanotubes, conferral of sequence-defined engineering and dynamic response characteristics to the tubules remains a challenge. Here we report a new family of highly-designable and dynamic single-walled nanotubes assembled from sequence-defined peptoids through a unique “rolling-up and closure of nanosheet” mechanism. During the assembly process, amorphous spherical particles of amphiphilic peptoid oligomers (APOs) crystallized to form well-defined nanosheets which were then folded to form single-walled peptoid nanotubes (SW-PNTs). These SW-PNTs undergo a pH-triggered, reversible contraction-expansion motion. By varying the number of hydrophobic residues of APOs, we demonstrate the tuning of PNT wall thickness andmore » diameter, and mechanical properties. AFM-based mechanical measurements indicate that PNTs are highly stiff (Young’s Modulus ~13-17 GPa), comparable to the stiffest known biological materials. We further demonstrate that the precise incorporation of functional groups within PNTs and the application of functional PNTs in water decontamination. We believe these SW-PNTs can provide a robust platform for development of biomimetic materials tailored to specific applications.« less

Bioinspired Design of Polycaprolactone Composite Nanofibers as Artificial Bone Extracellular Matrix for Bone Regeneration Application.

PubMed

Gao, Xiang; Song, Jinlin; Zhang, Yancong; Xu, Xiao; Zhang, Siqi; Ji, Ping; Wei, Shicheng

2016-10-07

The design and development of functional biomimetic systems for programmed stem cell response is a field of topical interest. To mimic bone extracellular matrix, we present an innovative strategy for constructing drug-loaded composite nanofibrous scaffolds in this study, which could integrate multiple cues from calcium phosphate mineral, bioactive molecule, and highly ordered fiber topography for the control of stem cell fate. Briefly, inspired by mussel adhesion mechanism, a polydopamine (pDA)-templated nanohydroxyapatite (tHA) was synthesized and then surface-functionalized with bone morphogenetic protein-7-derived peptides via catechol chemistry. Afterward, the resulting peptide-loaded tHA (tHA/pep) particles were blended with polycaprolactone (PCL) solution to fabricate electrospun hybrid nanofibers with random and aligned orientation. Our research demonstrated that the bioactivity of grafted peptides was retained in composite nanofibers. Compared to controls, PCL-tHA/pep composite nanofibers showed improved cytocompatibility. Moreover, the incorporated tHA/pep particles in nanofibers could further facilitate osteogenic differentiation potential of human mesenchymal stem cells (hMSCs). More importantly, the aligned PCL-tHA/pep composite nanofibers showed more osteogenic activity than did randomly oriented counterparts, even under nonosteoinductive conditions, indicating excellent performance of biomimetic design in cell fate decision. After in vivo implantation, the PCL-tHA/pep composite nanofibers with highly ordered structure could significantly promote the regeneration of lamellar-like bones in a rat calvarial critical-sized defect. Accordingly, the presented strategy in our work could be applied for a wide range of potential applications in not only bone regeneration application but also pharmaceutical science.

A Review of Potential Marine-derived Hypotensive and Anti-obesity Peptides.

PubMed

Manikkam, V; Vasiljevic, T; Donkor, O N; Mathai, M L

2016-01-01

Bioactive peptides are food derived components, usually consisting of 3-20 amino acids, which are inactive when incorporated within their parent protein. Once liberated by enzymatic or chemical hydrolysis, during food processing and gastrointestinal transit, they can potentially provide an array of health benefits to the human body. Owing to an unprecedented increase in the worldwide incidence of obesity and hypertension, medical researchers are focusing on the hypotensive and anti-obesity properties of nutritionally derived bioactive peptides. The role of the renin-angiotensin system has long been established in the aetiology of metabolic diseases and hypertension. Targeting the renin-angiotensin system by inhibiting the activity of angiotensin-converting enzyme (ACE) and preventing the formation of angiotensin II can be a potential therapeutic approach to the treatment of hypertension and obesity. Fish-derived proteins and peptides can potentially be excellent sources of bioactive components, mainly as a source of ACE inhibitors. However, increased use of marine sources, poses an unsustainable burden on particular fish stocks, so, the underutilized fish species and by-products can be exploited for this purpose. This paper provides an overview of the techniques involved in the production, isolation, purification, and characterization of bioactive peptides from marine sources, as well as the evaluation of the ACE inhibitory (ACE-I) activity and bioavailability.

Electrostatic Control of Bioactivity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberger, Joshua E.; Berns, Eric J.; Bitton, Ronit

2012-03-15

The power of independence: When exhibited on the surface of self-assembling peptide-amphiphile nanofibers, the hydrophobic laminin-derived IKVAV epitope induced nanofiber bundling through interdigitation with neighboring fibers and thus decreased the bioactivity of the resulting materials. The inclusion of charged amino acids in the peptide amphiphiles disrupted the tendency to bundle and led to significantly enhanced neurite outgrowth.

BG-4, a novel bioactive peptide from Momordica charantia, inhibits lipopolysaccharide-induced inflammation in THP-1 human macrophages

USDA-ARS?s Scientific Manuscript database

Background: Bitter melon (Momordica charantia) is a commonly used food crop for management of a variety of diseases most notably for control of diabetes, a disease associated with aberrant inflammation. Purpose: To evaluate the anti-inflammatory property of BG-4, a novel bioactive peptide isolated f...

Design of Chemical Conjugate for Targeted Therapy of Multiple Sclerosis Based of Constant Fragment of Human Antibody Heavy Chain and Peptoid Analog of Autoantigen MOG35-55.

PubMed

Lomakin, Y A; Stepanov, A V; Balabashin, D S; Ponomarenko, N A; Smirnov, I V; Belogurov, A A

2017-04-01

Elimination of B cells producing autoantibodies to neuroantigens is considered as beneficial in the treatment of multiple sclerosis. Myelin oligodendrocyte glycoprotein (MOG) is a significant autoantigen in multiple sclerosis. It was shown that MOG-like peptoid AMogP3 can bind autoantibodies produced by pathological lymphocytes. We propose a structure of an innovative drug for targeted elimination of the pool of autoreactive B cells responsible for multiple sclerosis pathogenesis; this compound is a complex of peptoid AMogP3 with Fc fragment of human immunoglobulin. The obtained Fc-PEG-AMogP3 conjugate effectively interact with autoreactive antibodies, which attests to their high therapeutic potential.

Neural tissue engineering: Bioresponsive nanoscaffolds using engineered self-assembling peptides.

PubMed

Koss, K M; Unsworth, L D

2016-10-15

Rescuing or repairing neural tissues is of utmost importance to the patient's quality of life after an injury. To remedy this, many novel biomaterials are being developed that are, ideally, non-invasive and directly facilitate neural wound healing. As such, this review surveys the recent approaches and applications of self-assembling peptides and peptide amphiphiles, for building multi-faceted nanoscaffolds for direct application to neural injury. Specifically, methods enabling cellular interactions with the nanoscaffold and controlling the release of bioactive molecules from the nanoscaffold for the express purpose of directing endogenous cells in damaged or diseased neural tissues is presented. An extensive overview of recently derived self-assembling peptide-based materials and their use as neural nanoscaffolds is presented. In addition, an overview of potential bioactive peptides and ligands that could be used to direct behaviour of endogenous cells are categorized with their biological effects. Finally, a number of neurotrophic and anti-inflammatory drugs are described and discussed. Smaller therapeutic molecules are emphasized, as they are thought to be able to have less potential effect on the overall peptide self-assembly mechanism. Options for potential nanoscaffolds and drug delivery systems are suggested. Self-assembling nanoscaffolds have many inherent properties making them amenable to tissue engineering applications: ease of synthesis, ease of customization with bioactive moieties, and amenable for in situ nanoscaffold formation. The combination of the existing knowledge on bioactive motifs for neural engineering and the self-assembling propensity of peptides is discussed in specific reference to neural tissue engineering. Copyright © 2016. Published by Elsevier Ltd.

Peptidomics approach to elucidate the proteolytic regulation of bioactive peptides

PubMed Central

Kim, Yun-Gon; Lone, Anna Mari; Nolte, Whitney M.; Saghatelian, Alan

2012-01-01

Peptide hormones and neuropeptides have important roles in physiology and therefore the regulation of these bioactive peptides is of great interest. In some cases proteolysis controls the concentrations and signaling of bioactive peptides, and the peptidases that mediate this biochemistry have proven to be extremely successful drug targets. Due to the lack of any general method to identify these peptidases, however, the role of proteolysis in the regulation of most neuropeptides and peptide hormones is unknown. This limitation prompted us to develop an advanced peptidomics-based strategy to identify the peptidases responsible for the proteolysis of significant bioactive peptides. The application of this approach to calcitonin gene-related peptide (CGRP), a neuropeptide associated with blood pressure and migraine, revealed the endogenous CGRP cleavage sites. This information was then used to biochemically purify the peptidase capable of proteolysis of CGRP at those cleavage sites, which led to the identification of insulin-degrading enzyme (IDE) as a candidate CGRP-degrading enzyme. CGRP had not been identified as an IDE substrate before and we tested the physiological relevance of this interaction by quantitative measurements of CGRP using IDE null (IDE−/−) mice. In the absence of IDE, full-length CGRP levels are elevated in vivo, confirming IDE as an endogenous CGRP-degrading enzyme. By linking CGRP and IDE, this strategy uncovers a previously unknown pathway for CGRP regulation and characterizes an additional role for IDE. More generally, this work suggests that this may be an effective general strategy for characterizing these pathways and peptidases moving forward. PMID:22586115

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. In this mini-review, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. The challenges and opportunitiesmore » in this new field are also discussed.« less

The action of neutrophil serine proteases on elastin and its precursor.

PubMed

Heinz, Andrea; Jung, Michael C; Jahreis, Günther; Rusciani, Anthony; Duca, Laurent; Debelle, Laurent; Weiss, Anthony S; Neubert, Reinhard H H; Schmelzer, Christian E H

2012-01-01

This study aimed to investigate the degradation of the natural substrates tropoelastin and elastin by the neutrophil-derived serine proteases human leukocyte elastase (HLE), proteinase 3 (PR3) and cathepsin G (CG). Focus was placed on determining their cleavage site specificities using mass spectrometric techniques. Moreover, the release of bioactive peptides from elastin by the three proteases was studied. Tropoelastin was comprehensively degraded by all three proteases, whereas less cleavage occurred in mature cross-linked elastin. An analysis of the cleavage site specificities of the three proteases in tropoelastin and elastin revealed that HLE and PR3 similarly tolerate hydrophobic and/or aliphatic amino acids such as Ala, Gly and Val at P(1), which are also preferred by CG. In addition, CG prefers the bulky hydrophobic amino acid Leu and accepts the bulky aromatic amino acids Phe and Tyr. CG shows a strong preference for the charged amino acid Lys at P(1) in tropoelastin, whereas Lys was not identified at P(1) in CG digests of elastin due to extensive cross-linking at Lys residues in mature elastin. All three serine proteases showed a clear preference for Pro at P(2) and P(4)'. With respect to the liberation of potentially bioactive peptides from elastin, the study revealed that all three serine proteases have a similar ability to release bioactive sequences, with CG producing the highest number of these peptides. In bioactivity studies, potentially bioactive peptides that have not been investigated on their bioactivity to date, were tested. Three new bioactive GxxPG motifs were identified; GVYPG, GFGPG and GVLPG. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

Hierarchical structures based on self-assembling beta-hairpin peptides and their application as biomaterials and hybrid materials

NASA Astrophysics Data System (ADS)

Altunbas, Aysegul

Self-assembly represents a robust and powerful paradigm for the bottom-up construction of nanostructures. Self-assembled peptide hydrogels are emerging as promising routes to novel multifunctional materials. The 20 amino acid MAX1and MAX8 peptides self-assemble into a three dimensional network of entangled, branched fibrils rich in beta-sheet secondary structure with a high density of lysine groups exposed on the fibril-surfaces. These hydrogels form self-supporting structures that shear thin upon application of shear and then immediately recover to a solid hydrogel upon cessation of shear which facilitates the local delivery of the hydrogel into a site in vivo. Templated condensation of silica precursors on self-assembled nanoscale peptide fibrils with various surface functionalities can be used to mimic biosilicification. This template-defined approach towards biomineralization was utilized for the controlled fabrication of 3D hybrid nanostructures. We report a study on the structure-property relationship of self-assembled peptide hydrogels where mineralization of individual fibrils through sol-gel chemistry was achieved. The nanostructure and consequent mechanical characteristics of these hybrid networks can be modulated by changing the stoichiometric parameters of the sol-gel process. Construction of such organic-inorganic hybrid networks by sol-gel processing of self-assembled peptide hydrogels has improved mechanical properties and resulted in materials with ˜ 3 orders of magnitude higher stiffness. The physical characterization of the hybrid networks via electron microscopy and small angle scattering is detailed and correlated with changes in the network mechanical behavior. The resultant high fidelity templating process suggests that the peptide substrate can be used to template the coating of other functional inorganic materials. Self-assembling peptide hydrogels encapsulating an anti-tumorigenic drug, curcumin, have been prepared and demonstrated to be an effective vehicle for the localized delivery of curcumin over sustained periods of time in vitro. The curcumin-hydrogel is prepared in-situ where curcumin encapsulation within the hydrogel network is accomplished concurrently with peptide self-assembly. Physical characterization methods and in vitro biological studies were used to demonstrate the effectiveness of curcumin-loaded beta-hairpin hydrogels as injectable agents for localized curcumin delivery. Notably, rheological characterization of the curcumin loaded hydrogel before and after shear flow have indicated solid-like properties even at high curcumin payloads. In vitro experiments with a medulloblastoma cell line confirm that the encapsulation of the curcumin within the hydrogel does not have an adverse effect on its bioactivity. Most importantly, the rate of curcumin release and its consequent therapeutic efficacy can be conveniently modulated by changing the morphological characteristics of the peptide hydrogel network. Lastly, MAX8 hydrogel cytocompatibility and biocompatibility was assessed with the future aim of utilizing this hydrogel as a scaffold in liver regeneration studies in rats. MAX8 hydrogel cytotoxity was evaluated using MC3T3-E1 and MG63 cell lines. Encapsulation, syringe delivery and subsequent viability of MG63 cells in hydrogels was also assessed to study the feasibility of using hydrogel/cell constructs as minimally invasive cell delivery vehicles. Biocompatibility was evaluated by monitoring inflammatory response induced by the MAX8 hydrogel via a subcutaneous mice model. Biocompatibility of MAX8 hydrogels at sites other than the subcutaneous region was also investigated using a cylindrical punch resection model in rat liver. The preliminary biocompatibility studies provide an elemental understanding of MAX8 hydrogel behavior in vivo.

Peptidome characterization and bioactivity analysis of donkey milk.

PubMed

Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2015-04-24

Donkey milk is an interesting commercial product for its nutritional values, which make it the most suitable mammalian milk for human consumption, and for the bioactivity associated with it and derivative products. To further mine the characterization of donkey milk, an extensive peptidomic study was performed. Two peptide purification strategies were compared to remove native proteins and lipids and enrich the peptide fraction. In one case the whole protein content was precipitated by organic solvent using cold acetone. In the other one the precipitation of the most abundant milk proteins, caseins, was performed under acidic conditions by acetic acid at pH4.6, instead. The procedures were compared and proved to be partially complementary. Considered together they provided 1330 peptide identifications for donkey milk, mainly coming from the most abundant proteins in milk. The bioactivity of the isolated peptides was also investigated, both by angiotensin-converting-enzyme inhibitory and antioxidant activity assays and by bioinformatics, proving that the isolated peptides did have the tested biological activities. The rationale behind this study is that peptides in food matrices often play an important biological role and, despite the extensive study of the protein composition of different samples, they remain poorly characterized. In fact, in a typical shotgun proteomics study endogenous peptides are not properly characterized. In proteomics workflows one limiting point is the isolation process: if it is specific for the purification of proteins, it often comprises a precipitation step which aims at isolating pure protein pellets and remove unwonted interferent compounds. In this way endogenous peptides, which are not effectively precipitated as well as proteins, are removed too and not analyzed at the end of the process. Moreover, endogenous peptides do often originate from precursor proteins, but in phenomena which are independent of the shotgun digestion protocol, thus they can be obtained from cleavage specificities other than trypsin's, which is the main proteolytic enzyme employed in proteomic experiments. For this reason, in the end, database search will not be effective for identification of these peptides, thus the need to provide different workflows for peptide analysis. In the work presented in this paper this issue is considered for the first time for the analysis of the peptides isolated in donkey milk samples, which have been chosen for its nutritional interest. This study provides additional knowledge on this milk, already characterized by traditional proteomics studies and peptidomic studies after simulated digestion. This type of study is not just a description of the naturally occurring peptidome of a sample, but also represents a starting point to discover and characterize those naturally occurring peptides responsible for the observed bioactivities of biological samples, as in the case of donkey milk, which would remain uncharacterized by other approaches. In this paper an analytical protocol was described for the efficient isolation and purification of peptides in donkey milk, assessing the effect of the purification protocol on the final identifications. Purified peptide samples were also checked to empirically elucidate any ACE inhibitory or antioxidant activity. Finally, the peptidomic results were also further mined by a bioinformatic-driven approach for bioactive peptide identification in the donkey milk samples. In our opinion, the main strengths of this study are related to the improved analytical workflow (either as purification protocol comparison or analytical platform development) which provides a high number of identified peptides, for which the biological significance as potential bioactive peptides has also been investigated. Copyright © 2015 Elsevier B.V. All rights reserved.

Peptide Fractions Obtained from Rice By-Products by Means of an Environment-Friendly Process Show In Vitro Health-Related Bioactivities

PubMed Central

Ferri, Maura; Graen-Heedfeld, Jürgen; Bretz, Karlheinz; Guillon, Fabien; Michelini, Elisa; Calabretta, Maria Maddalena; Lamborghini, Matteo; Gruarin, Nicolò; Roda, Aldo; Kraft, Axel

2017-01-01

Recently, the isolation of new health-related bioactive molecules derived from agro-food industrial by-products by means of environment-friendly extraction processes has become of particular interest. In the present study, a protein by-product from the rice starch industry was hydrolysed with five commercial proteolytic enzymes, avoiding the use of solvents or chemicals. The digestion processes were optimised, and the digestates were separated in fractions with four different molecular weight ranges by using a cross-flow membrane filtration technique. Total hydrolysates and fractions were tested in vitro for a wide range of biological activities. For the first time rice-derived peptides were assayed for anti-tyrosinase, anti-inflammatory, cytotoxicity and irritation capacities. Antioxidant and anti-hypertensive activities were also evaluated. Protamex, Alcalase and Neutrase treatments produced peptide fractions with valuable bioactivities without resulting cytotoxic or irritant. Highest levels of bioactivity were detected in Protamex-derived samples, followed by samples treated with Alcalase. Based on the present results, a future direct exploitation of isolated peptide fractions in the nutraceutical, functional food and cosmetic industrial fields may be foreseen. PMID:28125712

Peptide profiling of bovine kefir reveals 236 unique peptides released from caseins during its production by starter culture or kefir grains.

PubMed

Ebner, Jennifer; Aşçı Arslan, Ayşe; Fedorova, Maria; Hoffmann, Ralf; Küçükçetin, Ahmet; Pischetsrieder, Monika

2015-03-18

Kefir has a long tradition in human nutrition due to its presupposed health promoting effects. To investigate the potential contribution of bioactive peptides to the physiological effects of kefir, comprehensive analysis of the peptide profile was performed by nano-ESI-LTQ-Orbitrap MS coupled to nano-ultrahigh-performance liquid chromatography. Thus, 257 peptides were identified, mainly released from β-casein, followed by αS1-, κ-, and αS2-casein. Most (236) peptides were uniquely detected in kefir, but not in raw milk indicating that the fermentation step does not only increase the proteolytic activity 1.7- to 2.4-fold compared to unfermented milk, but also alters the composition of the peptide fraction. The influence of the microflora was determined by analyzing kefir produced from traditional kefir grains or commercial starter culture. Kefir from starter culture featured 230 peptide sequences and showed a significantly, 1.4-fold higher proteolytic activity than kefir from kefir grains with 127 peptides. A match of 97 peptides in both varieties indicates the presence of a typical kefir peptide profile that is not influenced by the individual composition of the microflora. Sixteen of the newly identified peptides were previously described as bioactive, including angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, immunomodulating, opioid, mineral binding, antioxidant, and antithrombotic effects. The present study describes a comprehensive peptide profile of kefir comprising 257 sequences. The peptide list was used to identify 16 bioactive peptides with ACE-inhibitory, antioxidant, antithrombotic, mineral binding, antimicrobial, immunomodulating and opioid activity in kefir. Furthermore, it was shown that a majority of the kefir peptides were not endogenously present in the raw material milk, but were released from milk caseins by proteases of the microbiota and are therefore specific for the product. Consequently, the proteolytic activity and the composition of the peptide profile can be controlled by the applied microflora (grains or starter culture). On the other hand, a considerable portion of the peptide profile was identified to be typical for kefir in general and independent from production parameters. In summary, the generated kefir peptide profile helped to reveal its origin and to identify bioactive peptides in kefir, which may advance the understanding of health benefits of this food product. The results further indicate that subsets of the kefir peptide list can be used as markers to control food authenticity, for example, to distinguish different types of kefir. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly stable and self-repairing membrane-mimetic 2D nanomaterials assembled from lipid-like peptoids

DOE PAGES

Jin, Haibao; Jiao, Fang; Daily, Michael D.; ...

2016-07-12

Two-dimensional (2D) materials with molecular-scale thickness have attracted increasing interest for separation, electronic, catalytic, optical, energy and biomedical applications. Although extensive research on 2D materials, such as graphene and graphene oxide, has been performed in recent years, progress is limited on self-assembly of 2D materials from sequence-specific macromolecules, especially from synthetic sequences that could exhibit lipid-like self-assembly of bilayer sheets and mimic membrane proteins for functions. The creation of such new class of materials could enable development of highly stable biomimetic membranes that exhibit cell-membrane-like molecular transport with exceptional selectively and high transport rates. Here we demonstrate self-assembly of lipid-likemore » 12-mer peptoids into extremely stable, crystalline, flexible and free-standing 2D membrane materials. As with cell membranes, upon exposure to external stimuli, these materials exhibit changes in thickness, varying from 3.5 nm to 5.6 nm. We find that self-assembly occurs through a facile crystallization process, in which inter-peptoid hydrogen bonds and enhanced hydrophobic interactions drive the formation of a highly-ordered structure. Molecular simulation confirms this is the energetically favored structure. Displaying functional groups at arbitrary locations of membrane-forming peptoids produces membranes with similar structures. This research further shows that single-layer membranes can be coated onto substrate surfaces. Moreover, membranes with mechanically-induced defects can self-repair. Given that peptoids are sequence-specific and exhibit protein-like molecular recognition with enhanced stability, we anticipate our membranes to be a robust platform tailored to specific applications.« less

Highly stable and self-repairing membrane-mimetic 2D nanomaterials assembled from lipid-like peptoids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Haibao; Jiao, Fang; Daily, Michael D.

Two-dimensional (2D) materials with molecular-scale thickness have attracted increasing interest for separation, electronic, catalytic, optical, energy and biomedical applications. Although extensive research on 2D materials, such as graphene and graphene oxide, has been performed in recent years, progress is limited on self-assembly of 2D materials from sequence-specific macromolecules, especially from synthetic sequences that could exhibit lipid-like self-assembly of bilayer sheets and mimic membrane proteins for functions. The creation of such new class of materials could enable development of highly stable biomimetic membranes that exhibit cell-membrane-like molecular transport with exceptional selectively and high transport rates. Here we demonstrate self-assembly of lipid-likemore » 12-mer peptoids into extremely stable, crystalline, flexible and free-standing 2D membrane materials. As with cell membranes, upon exposure to external stimuli, these materials exhibit changes in thickness, varying from 3.5 nm to 5.6 nm. We find that self-assembly occurs through a facile crystallization process, in which inter-peptoid hydrogen bonds and enhanced hydrophobic interactions drive the formation of a highly-ordered structure. Molecular simulation confirms this is the energetically favored structure. Displaying functional groups at arbitrary locations of membrane-forming peptoids produces membranes with similar structures. This research further shows that single-layer membranes can be coated onto substrate surfaces. Moreover, membranes with mechanically-induced defects can self-repair. Given that peptoids are sequence-specific and exhibit protein-like molecular recognition with enhanced stability, we anticipate our membranes to be a robust platform tailored to specific applications.« less

PAL-12, a new anti-aging hexa-peptoid, inhibits UVB-induced photoaging in human dermal fibroblasts and 3D reconstructed human full skin model, Keraskin-FT™.

PubMed

Song, Daeun; Park, Hyeonji; Lee, Su-Hyon; Kim, Mi Jung; Kim, Eun-Joo; Lim, Kyung-Min

2017-11-01

Peptoids are a class of peptidomimetics whose pharmacological activities are widely investigated owing to their remarkable biological stability. However, the utilities of peptoids as cosmetic functional ingredients have not been fully explored. Here, we investigated anti-aging effects of PAL-12, a new hexa-peptoid, on UVB-induced photoaging in human dermal fibroblasts (HDFs) and a 3D reconstituted human full skin model, Keraskin-FT™. PAL-12 suppressed matrix metalloproteinase-1 (MMP-1) expression induced by UVB irradiation along with the attenuation of MMP-1 secretion as determined by ELISA assay. Interestingly PAL-12 slightly enhanced the expression levels of collagen-1 and fibronectin-1 in HDFs or Keraskin-FT™. In addition, PAL-12 prevented the decrease of cell viability following UVB irradiation. However, PAL-12 failed to affect ROS generation, cell necrosis and apoptosis significantly. Instead, PAL-12 suppressed UVB-induced activation of epidermal growth factor receptors (EGFR), extracellular signal-regulated kinase (ERK) and c-Jun, which may resulted in the attenuation of AP-1-promoted MMP-1 expression. Collectively, these results suggest that PAL-12 might be a novel cosmetic ingredient effective against UVB-induced skin photoaging.

Molecular targets of antihypertensive peptides: understanding the mechanisms of action based on the pathophysiology of hypertension.

PubMed

Majumder, Kaustav; Wu, Jianping

2014-12-24

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides.

Molecular Targets of Antihypertensive Peptides: Understanding the Mechanisms of Action Based on the Pathophysiology of Hypertension

PubMed Central

Majumder, Kaustav; Wu, Jianping

2014-01-01

There is growing interest in using functional foods or nutraceuticals for the prevention and treatment of hypertension or high blood pressure. Although numerous preventive and therapeutic pharmacological interventions are available on the market, unfortunately, many patients still suffer from poorly controlled hypertension. Furthermore, most pharmacological drugs, such as inhibitors of angiotensin-I converting enzyme (ACE), are often associated with significant adverse effects. Many bioactive food compounds have been characterized over the past decades that may contribute to the management of hypertension; for example, bioactive peptides derived from various food proteins with antihypertensive properties have gained a great deal of attention. Some of these peptides have exhibited potent in vivo antihypertensive activity in both animal models and human clinical trials. This review provides an overview about the complex pathophysiology of hypertension and demonstrates the potential roles of food derived bioactive peptides as viable interventions targeting specific pathways involved in this disease process. This review offers a comprehensive guide for understanding and utilizing the molecular mechanisms of antihypertensive actions of food protein derived peptides. PMID:25547491

Sustained release of hepatocyte growth factor by cationic self-assembling peptide/heparin hybrid hydrogel improves β-cell survival and function through modulating inflammatory response

PubMed Central

Liu, Shuyun; Zhang, Lanlan; Cheng, Jingqiu; Lu, Yanrong; Liu, Jingping

2016-01-01

Inflammatory response is a major cause of grafts dysfunction in islet transplantation. Hepatocyte growth factor (HGF) had shown anti-inflammatory activity in multiple diseases. In this study, we aim to deliver HGF by self-assembling peptide/heparin (SAP/Hep) hybrid gel to protect β-cell from inflammatory injury. The morphological and slow release properties of SAPs were analyzed. Rat INS-1 β-cell line was treated with tumor necrosis factor α in vitro and transplanted into rat kidney capsule in vivo, and the viability, apoptosis, function, and inflammation of β-cells were evaluated. Cationic KLD1R and KLD2R self-assembled to nanofiber hydrogel, which showed higher binding affinity for Hep and HGF because of electrostatic interaction. Slow release of HGF from cationic SAP/Hep gel is a two-step mechanism involving binding affinity with Hep and molecular diffusion. In vitro and in vivo results showed that HGF-loaded KLD2R/Hep gel promoted β-cell survival and insulin secretion, and inhibited cell apoptosis, cytokine release, T-cell infiltration, and activation of NFκB/p38 MAPK pathways in β-cells. This study suggested that SAP/Hep gel is a promising carrier for local delivery of bioactive proteins in islet transplantation. PMID:27729786

New bioactive bone-like microspheres with intrinsic magnetic properties obtained by bio-inspired mineralisation process.

PubMed

Fernandes Patrício, Tatiana Marisa; Panseri, Silvia; Sandri, Monica; Tampieri, Anna; Sprio, Simone

2017-08-01

A bio-inspired mineralisation process was investigated and applied to develop novel hybrid magnetic materials by heterogeneous nucleation of Fe 2+ /Fe 3+ -doped hydroxyapatite nanocrystals onto a biopolymeric matrix made of a Type I collagen-based recombinant peptide (RCP). The effect of the synthesis temperature on the phase composition, crystallinity and magnetic properties of the nucleated inorganic phase was studied. The as-obtained magnetic materials were then engineered, by using a water-in-oil emulsification process, into hybrid magnetic microspheres, which were stabilized by de-hydrothermal treatment yielding cross-linking of the macromolecular matrix. Thorough investigation of the physicochemical, morphological and biological properties of the new hybrid microspheres, as induced by the presence of the inorganic nanophase and controlled iron substitution into hydroxyapatite lattice, revealed bone-like composition, good cytocompatibility, designed shape and size, and tailored magnetization. Such features are interesting and promising for application as new biomaterials with ability of remote activation and control by using external magnetic fields, for smart and personalized applications in medicine, particularly in bone tissue regeneration. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface chemical immobilization of bioactive peptides on synthetic polymers for cardiac tissue engineering.

PubMed

Rosellini, Elisabetta; Cristallini, Caterina; Guerra, Giulio D; Barbani, Niccoletta

2015-01-01

The aim of this work was the development of new synthetic polymeric systems, functionalized by surface chemical modification with bioactive peptides, for myocardial tissue engineering. Polycaprolactone and a poly(ester-ether-ester) block copolymer synthesized in our lab, polycaprolactone-poly(ethylene oxide)-polycaprolactone (PCL-PEO-PCL), were used as the substrates to be modified. Two pentapeptides, H-Gly-Arg-Gly-Asp-Ser-OH (GRGDS) from fibronectin and H-Tyr-Ile-Gly-Ser-Arg-OH (YIGSR) from laminin, were used for the functionalization. Polymeric membranes were obtained by casting from solutions and then functionalized by means of alkaline hydrolysis and subsequent coupling of the bioactive molecules through 1-(3-dimethylaminopropyl)-3-ethylcarbodimide hydrochloride/N-hydroxysuccinimide chemistry. The hydrolysis conditions, in terms of hydrolysis time, temperature, and sodium hydroxide concentration, were optimized for the two materials. The occurrence of the coupling reaction was demonstrated by infrared spectroscopy, as the presence on the functionalized materials of the absorption peaks typical of the two peptides. The peptide surface density was determined by chromatographic analysis and the distribution was studied by infrared chemical imaging. The results showed a nearly homogeneous peptide distribution, with a density above the minimum value necessary to promote cell adhesion. Preliminary in vitro cell culture studies demonstrated that the introduction of the bioactive molecules had a positive effect on improving C2C12 myoblasts growth on the synthetic materials.

Synthesis of bioactive organic-inorganic nanohybrid for bone repair through sol-gel processing.

PubMed

Miyazaki, Toshiki; Ohtsuki, Chikara; Tanihara, Masao

2003-12-01

So-called bioactive ceramics have been attractive because they form bone-like apatite on their surfaces to bond directly to living bone when implanted in bony defects. However, they are much more brittle and much less flexible than natural bone. Organic-inorganic hybrids consisting of flexible organic polymers and the essential constituents of the bioactive ceramics (i.e., Si-OH groups and Ca2+ ions) are useful as novel bone substitutes, because of their bioactivity and mechanical properties analogous to those of natural bone. In the present study, organic-inorganic nanohybrids were synthesized from hydroxyethylmethacrylate (HEMA) and methacryloxypropyltrimethoxysilane (MPS), as well as various calcium salts. Bioactivity of the synthesized hybrids was assessed in vitro by examining their acceptance of apatite deposition in simulated body fluid (Kokubo solution). The prepared hybrids formed apatite in Kokubo solution when they were modified with calcium chloride (CaCl2) at 5 or 10 mol% of the total of MPS and HEMA. Deposition of a kind of calcium phosphate was observed for the hybrids modified with calcium acetate (Ca(CH3COO)2), although it could not be identified with apatite. The addition of glycerol up to 10 mol% of the total of MPS and HEMA or water up to 20 mol% as plasticizers did not appreciably decrease the acceptance of apatite formation of the hybrids. These findings allow wide selectivity in the design of bioactive nanohybrids developed by organic modification of the Si-OH group and calcium ion through sol-gel processing. Such nanohybrids have potential as novel bone substitutes with both high bioactivity and high flexibility.

Brazilian Kefir-Fermented Sheep's Milk, a Source of Antimicrobial and Antioxidant Peptides.

PubMed

de Lima, Meire Dos Santos Falcão; da Silva, Roberto Afonso; da Silva, Milena Fernandes; da Silva, Paulo Alberto Bezerra; Costa, Romero Marcos Pedrosa Brandão; Teixeira, José António Couto; Porto, Ana Lúcia Figueiredo; Cavalcanti, Maria Taciana Holanda

2017-12-28

Fermented milks are a source of bioactive peptides and may be considered as functional foods. Among these, sheep's milk fermented with kefir has not been widely studied and its most relevant properties need to be more thoroughly characterized. This research study is set out to investigate and evaluate the antioxidant and antimicrobial properties of peptides from fermented sheep's milk in Brazil when produced by using kefir. For this, the chemical and microbiological composition of the sheep's milk before and after the fermentation was evaluated. The changes in the fermented milk and the peptides extracted before the fermentation and in the fermented milk during its shelf life were verified. The antimicrobial and antioxidant activities of the peptides from the fermented milk were evaluated and identified according to the literature. The physicochemical properties and mineral profile of the fermented milk were like those of fresh milk. The peptide extract presented antimicrobial activity and it was detected that 13 of the 46 peptides were able to inhibit the growth of pathogenic microorganisms. A high antioxidant activity was observed in the peptides extracted from fermented milk (3.125 mg/mL) on the 28th day of storage. Two fractions displayed efficient radical scavenging properties by DPPH and ABTS methods. At least 11 peptides distributed in the different fractions were identified by tandem mass spectrometry. This sheep's milk fermented by Brazilian kefir grains, which has antioxidant and antimicrobial activities and probiotic microorganisms, is a good candidate for further investigation as a source for bioactive peptides. The fermentation process was thus a means by which to produce potential bioactive peptides.

Divergent unprotected peptide macrocyclisation by palladium-mediated cysteine arylation.

PubMed

Rojas, Anthony J; Zhang, Chi; Vinogradova, Ekaterina V; Buchwald, Nathan H; Reilly, John; Pentelute, Bradley L; Buchwald, Stephen L

2017-06-01

Macrocyclic peptides are important therapeutic candidates due to their improved physicochemical properties in comparison to their linear counterparts. Here we detail a method for a divergent macrocyclisation of unprotected peptides by crosslinking two cysteine residues with bis-palladium organometallic reagents. These synthetic intermediates are prepared in a single step from commercially available aryl bis-halides. Two bioactive linear peptides with cysteine residues at i , i + 4 and i , i + 7 positions, respectively, were cyclised to introduce a diverse array of aryl and bi-aryl linkers. These two series of macrocyclic peptides displayed similar linker-dependent lipophilicity, phospholipid affinity, and unique volume of distributions. Additionally, one of the bioactive peptides showed target binding affinity that was predominantly affected by the length of the linker. Collectively, this divergent strategy allowed rapid and convenient access to various aryl linkers, enabling the systematic evaluation of the effect of appending unit on the medicinal properties of macrocyclic peptides.

Collagen-binding VEGF mimetic peptide: Structure, matrix interaction, and endothelial cell activation

NASA Astrophysics Data System (ADS)

Chan, Tania R.

Long term survival of artificial tissue constructs depends greatly on proper vascularization. In nature, differentiation of endothelial cells and formation of vasculature are directed by dynamic spatio-temporal cues in the extracellular matrix that are difficult to reproduce in vitro. In this dissertation, we present a novel bifunctional peptide that mimics matrix-bound vascular endothelial growth factor (VEGF), which can be used to encode spatially controlled angiogenic signals in collagen-based scaffolds. The peptide, QKCMP, contains a collagen mimetic domain (CMP) that binds to type I collagen by a unique triple helix hybridization mechanism and a VEGF mimetic domain (QK) with pro-angiogenic activity. We demonstrate QKCMP's ability to hybridize with native and heat denatured collagens through a series of binding studies on collagen and gelatin substrates. Circular dichroism experiments show that the peptide retains the triple helical structure vital for collagen binding, and surface plasmon resonance study confirms the molecular interaction between the peptide and collagen strands. Cell culture studies demonstrate QKCMP's ability to induce endothelial cell morphogenesis and network formation as a matrix-bound factor in 2D and 3D collagen scaffolds. We also show that the peptide can be used to spatially modify collagen-based substrates to promote localized endothelial cell activation and network formation. To probe the biological events that govern these angiogenic cellular responses, we investigated the cell signaling pathways activated by collagen-bound QKCMP and determined short and long-term endothelial cell response profiles for p38, ERK1/2, and Akt signal transduction cascades. Finally, we present our efforts to translate the peptide's in vitro bioactivity to an in vivo burn injury animal model. When implanted at the wound site, QKCMP functionalized biodegradable hydrogels induce enhanced neovascularization in the granulation tissue. The results show QKCMP's efficacy as a matrix-bound angiogenic factor that directs endothelial cell proliferation and migration. These findings suggest that QKCMP can be used to enhance microvasculature formation during wound healing as well as to promote spatially controlled microvasculature for tissue engineering applications.

Peptide modified nanofibrous scaffold promotes human mesenchymal stem cell proliferation and long-term passaging.

PubMed

Mobasseri, Rezvan; Tian, Lingling; Soleimani, Masoud; Ramakrishna, Seeram; Naderi-Manesh, Hossein

2018-03-01

Long-term culture, passage and proliferation of human mesenchymal stem cells (hMSCs) cause loss of their stemness properties including self-renewal and multipotency. By optimizing the MSCs environment in vitro, maintaining the stemness state and better controlling the cell fate might be possible. We have recently reported the significant effects of bioactive Tat protein-derived peptide named R-peptide on hMSC adhesion, morphology and proliferation, which has demonstrated R-peptide enhanced MSC early adhesion and proliferation in comparison to other bioactive molecules including RGD peptide, fibronectin and collagen. In this study, R-peptide was used to evaluate stemness properties of MSCs after long-term passaging. R-peptide conjugated poly caprolactone (PCL) nanofibrous scaffold and unmodified nanofibrous scaffold were used to study the impact of R-peptide modified PCL nanofibers and PCL nanofibers on cell behavior. The results showed early formation of focal adhesion (FA) complex on R-peptide modified scaffolds at 30min after cell seeding. The rate of cell proliferation was significantly increased due to presence of R-peptide, and the MSCs marker analyses using flow cytometry and immunocytochemistry staining proved the ability of R-peptide to maintain mesenchymal stem cell properties (high proliferation, expression of multipotent markers and differentiation capacity) even after long-term passage culturing. Accordingly, our (The) results concluded that bioactive R-peptide in combination with nanofibrous scaffold can mimic the native ECM comprising micro/nano architecture and biochemical molecules in a best way. The designed scaffold can link extracellular matrix (ECM) to nucleus via formation of FA and organization of cytoskeleton, causing fast and strong attachment of MSCs and allowing integrin-mediated signaling to start. Copyright © 2017 Elsevier B.V. All rights reserved.

HMC-1 human mast cells synthesize neurotensin (NT) precursor, secrete bioactive NT-like peptide(s) and express NT receptor NTS1.

PubMed

Cochrane, David E; Carraway, Robert E; Harrington, Kimberly; Laudano, Melissa; Rawlings, Stephen; Feldberg, Ross S

2011-12-01

To determine if mast cells synthesize the inflammatory peptide, neurotensin (NT), secrete immunoreactive and bioactive NT, and express the NT receptor NTS1. HMC-1 cells, pleural mast cells from Sprague-Dawley rats, LAD2 mast cells, and human cord blood mast cells were used. HMC-1 cells were stimulated with NT, C48/80, mastoparan, or PGE(2). For changes in cutaneous vascular permeability, anesthetized rats were injected intravenously with Evans Blue dye and intradermally with saline, NT, histamine, diphenhydramine, and C48/80. RT-PCR was used to identify RNA transcripts. Histamine was measured by fluorometric assay. In vivo cutaneous vascular permeability assays, radio-immunoassays for NT, Western blotting for the NT precursor protein and NTS1 protein from HMC-1 cells and tissues from rats were used. Immunohistochemistry was used to identify NT precursor-like proteins in HMC-1 mast cells. HMC-1 cells express mRNAs for NT precursor, PC5A processing enzyme and NTS1 receptor. Human cord blood mast cells and LAD2 mast cells express mRNA transcripts for NT precursor and NTS1. Western blotting showed NT precursor and NTS1 receptor in HMC1. Rat tissues with high numbers of mast cells contained NT precursor proteins. NT-like peptides from HMC-1 displayed NT-like bioactivity. HMC-1 mast cells synthesize and secrete immunoreactive and bioactive NT-like peptide(s) and express the NT receptor, suggesting that NT from mast cells might serve autocrine and paracrine roles.

The importance of key floral bioactive compounds to honey bees for the detection and attraction of hybrid vegetable crops and increased seed yield.

PubMed

Mas, Flore; Harper, Aimee; Horner, Rachael; Welsh, Taylor; Jaksons, Peter; Suckling, David M

2018-02-15

Crop breeding programmes generally select for traits for improved yield and human consumption preferences. Yet, they often overlook one fundamental trait essential for insect-pollinated crops: pollinator attraction. This is even more critical for hybrid plants that rely on cross-pollination between the male-fertile line and the male-sterile line to set seeds. This study investigated the role of floral odours for honey bee pollination that could explain the poor seed yield in hybrid crops. The key floral bioactive compounds that honey bees detect were identified for three vegetable hybrid crops. It was found that 30% of the variation in bioactive compound quantities was explained by variety. Differences in quantities of the bioactive compounds triggered different degrees of olfactory response and were also associated with varied appetitive response. Correlating the abundance of each bioactive compound with seed yield, it was found that aldehydes such as nonanal and decanal can have a strong negative influence on seed yield with increasing quantity. Using these methodologies to identify relevant bioactive compounds associated with honey bee pollination, plant breeding programmes should also consider selecting for floral traits attractive to honey bees to improve crop pollination for enhanced seed yield. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Comprehensive Peptide Analysis of Mouse Brain Striatum Identifies Novel sORF-Encoded Polypeptides.

PubMed

Budamgunta, Harshavardhan; Olexiouk, Volodimir; Luyten, Walter; Schildermans, Karin; Maes, Evelyne; Boonen, Kurt; Menschaert, Gerben; Baggerman, Geert

2018-04-30

Bio-active peptides are involved in the regulation of most physiological processes in the body. Classical bio-active peptides (CBAPs) are cleaved from a larger precursor protein and stored in secretion vesicles from which they are released in the extracellular space. Recently, another non-classical type of bio-active peptides (NCBAPs) have gained interest. These typically are not secreted but instead appear to be translated from short open reading frames (sORF) and released directly into the cytoplasm. In contrast to CBAPs, these peptides are involved in the regulation of intra-cellular processes such as transcriptional control, calcium handling and DNA repair. However, bio-chemical evidence for the translation of sORFs remains elusive. Comprehensive analysis of sORF-encoded polypeptides (SEPs) is hampered by a number of methodological and biological challenges: the low molecular mass (many 4-10 kDa), the low abundance, transient expression and complications in data analysis. We developed a strategy to address a number of these issues. Our strategy is to exclude false positive identifications. in total sample, we identified 926 peptides originated from 37 known (neuro)peptide precursors in mouse striatum,. In addition, four SEPs were identified including NoBody, a SEP that was previously discovered in humans and three novel SEPS from 5' untranslated transcript regions (UTRs). This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Non-Covalent Photo-Patterning of Gelatin Matrices Using Caged Collagen Mimetic Peptides

PubMed Central

Li, Yang; Hoa San, Boi; L. Kessler, Julian; Hwan Kim, Jin; Xu, Qingguo; Hanes, Justin; Yu, Seungju Michael

2015-01-01

Advancements in photolithography have enabled us to spatially encode biochemical cues in biocompatible platforms such as synthetic hydrogels. Conventional patterning works through photo-activated chemical reactions on inert polymer networks. However, these techniques cannot be directly applied to protein hydrogels without chemically altering the protein scaffolds. To this end, we developed a non-covalent photo-patterning strategy for gelatin (denatured collagen) hydrogels utilizing a caged collagen mimetic peptide (caged CMP) which binds to gelatin strands through UV activated, triple helix hybridization. Here we present 2D and 3D photo-patterning of gelatin hydrogels enabled by the caged CMPs as well as creation of concentration gradients of CMPs. We show that photo-patterning of PEG-conjugated caged CMPs can be used to spatially control cell adhesion on gelatin films. CMP’s specificity for binding to gelatin allows patterning of almost any synthetic or natural gelatin-containing matrix, such as zymograms, gelatin-methacrylate hydrogels, and even a corneal tissue. Since the CMP is a chemically and biologically inert peptide which is proven to be an ideal carrier for bioactive molecules, our patterning method provides a radically new tool for immobilizing drugs to natural tissues and for functionalizing scaffolds for complex tissue formation. PMID:25476588

Conformational analysis of a modified RGD adhesive sequence.

PubMed

Triguero, Jordi; Zanuy, David; Alemán, Carlos

2017-02-01

The conformational preferences of the Arg-GlE-Asp sequence, where GlE is an engineered amino acid bearing a 3,4-ethylenedioxythiophene (EDOT) ring as side group, have been determined combining density functional theory calculations with a well-established conformational search strategy. Although the Arg-GlE-Asp sequence was designed to prepare a conducting polymer-peptide conjugate with excellent electrochemical and bioadhesive properties, the behavior of such hybrid material as adhesive biointerface is improvable. Results obtained in this work prove that the bioactive characteristics of the parent Arg-Gly-Asp sequence become unstable in Arg-GlE-Asp because of both the steric hindrance caused by the EDOT side group and the repulsive interactions between the oxygen atoms belonging to the backbone amide groups and the EDOT side group. Detailed analyses of the conformational preferences identified in this work have been used to re-engineer the Arg-GlE-Asp sequence for the future development of a new electroactive conjugate with improved bioadhesive properties. The preparation of this new conjugate is in progress. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Assessment of multifunctional activity of bioactive peptides derived from fermented milk by specific Lactobacillus plantarum strains.

PubMed

Aguilar-Toalá, J E; Santiago-López, L; Peres, C M; Peres, C; Garcia, H S; Vallejo-Cordoba, B; González-Córdova, A F; Hernández-Mendoza, A

2017-01-01

Milk-derived bioactive peptides with a single activity (e.g., antioxidant, immunomodulatory, or antimicrobial) have been previously well documented; however, few studies describe multifunctional bioactive peptides, which may be preferred over single-activity peptides, as they can simultaneously trigger, modulate, or inhibit multiple physiological pathways. Hence, the aim of this study was to assess the anti-inflammatory, antihemolytic, antioxidant, antimutagenic, and antimicrobial activities of crude extracts (CE) and peptide fractions (<3 and 3-10 kDa) obtained from fermented milks with specific Lactobacillus plantarum strains. Overall, CE showed higher activity than both peptide fractions (<3 and 3-10 kDa) in most of the activities assessed. Furthermore, activity of <3 kDa was generally higher, or at least equal, to the 3 to 10 kDa peptide fractions. In particular, L. plantarum 55 crude extract or their fractions showed the higher anti-inflammatory (723.68-1,759.43μg/mL of diclofenac sodium equivalents), antihemolytic (36.65-74.45% of inhibition), and antioxidant activity [282.8-362.3µmol of Trolox (Sigma-Aldrich, St. Louis, MO) equivalents]. These results provide valuable evidence of multifunctional role of peptides derived of fermented milk by the action of specific L. plantarum strains. Thus, they may be considered for the development of biotechnological products to be used to reduce the risk of disease or to enhance a certain physiological function. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Biopeptides in Milk: Opiate and Antithrombotic Effects.

PubMed

Masood, Ramoona; Khosravi-Darani, Kianoush

2015-01-01

Recently, the concept of functional food can be seen worldwide, and there are several local wisdoms on health-conscious. In this context, the protein fractionation of\\milk has attracted interests. Casein-derived bioactives have been identified as showing several health beneficial bioactivities including opiate, antithrombotic, antioxidative, antimicrobial, osteoprotective, anticariogenic and growth-promoting. Peptides have to be absorbed from the intestine and reach the target cells in sufficient concentrations or act via receptors; then they can show health effects. In this review paper, the milk-derived peptides and their therapeutic effects are introduced. Also the opiate and antithrombotic effects of these peptides are described.

Antibody-Mimetic Peptoid Nanosheet for Label-Free Serum-Based Diagnosis of Alzheimer's Disease.

PubMed

Zhu, Ling; Zhao, Zijian; Cheng, Peng; He, Zhaohui; Cheng, Zhiqiang; Peng, Jiaxi; Wang, Huayi; Wang, Chen; Yang, Yanlian; Hu, Zhiyuan

2017-08-01

Alzheimer's disease (AD) is the most common form of dementia characterized by progressive cognitive decline. Current diagnosis of AD is based on symptoms, neuropsychological tests, and neuroimaging, and is usually evident years after the pathological process. Early assessment at the preclinical or prodromal stage is in a great demand since treatment after the onset can hardly stop or reverse the disease progress. However, early diagnosis of AD is challenging due to the lack of reliable noninvasive approaches. Here, an antibody-mimetic self-assembling peptoid nanosheet containing surface-exposed Aβ42-recognizing loops is constructed, and a label-free sensor for the detection of AD serum is developed. The loop-displaying peptoid nanosheet is demonstrated to have high affinity to serum Aβ42, and to be able to identify AD sera with high sensitivity. The dense distribution of molecular recognition loops on the robust peptoid nanosheet scaffold not only mimics the architecture of antibodies, but also reduces the nonspecific binding in detecting multicomponent samples. This antibody-mimetic 2D material holds great potential toward the blood-based diagnosis of AD, and meanwhile provides novel insights into the antibody alternative engineering and the universal application in biological and chemical sensors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Association of a peptoid ligand with the apical loop of pri-miR-21 inhibits cleavage by Drosha

PubMed Central

Diaz, Jason P.; Chirayil, Rachel; Chirayil, Sara; Tom, Martin; Head, Katie J.; Luebke, Kevin J.

2014-01-01

We have found a small molecule that specifically inhibits cleavage of a precursor to the oncogenic miRNA, miR-21, by the microprocessor complex of Drosha and DGCR8. We identified novel ligands for the apical loop of this precursor from a screen of 14,024 N-substituted oligoglycines (peptoids) in a microarray format. Eight distinct compounds with specific affinity were obtained, three having affinities for the targeted loop in the low micromolar range and greater than 15-fold discrimination against a closely related hairpin. One of these compounds completely inhibits microprocessor cleavage of a miR-21 primary transcript at concentrations at which cleavage of another miRNA primary transcript, pri-miR-16, is little affected. The apical loop of pri-miR-21, placed in the context of pri-miR-16, is sufficient for inhibition of microprocessor cleavage by the peptoid. This compound also inhibits cleavage of pri-miR-21 containing the pri-miR-16 apical loop, suggesting an additional site of association within pri-miR-21. The reported peptoid is the first example of a small molecule that inhibits microprocessor cleavage by binding to the apical loop of a pri-miRNA. PMID:24497550

Mechanisms of action and in vivo antibacterial efficacy assessment of five novel hybrid peptides derived from Indolicidin and Ranalexin against Streptococcus pneumoniae

PubMed Central

Jindal, Hassan Mahmood; Zandi, Keivan; Ong, Kien Chai; Velayuthan, Rukumani Devi; Rasid, Sara Maisha; Samudi Raju, Chandramathi

2017-01-01

Background Antimicrobial peptides (AMPs) are of great potential as novel antibiotics for the treatment of broad spectrum of pathogenic microorganisms including resistant bacteria. In this study, the mechanisms of action and the therapeutic efficacy of the hybrid peptides were examined. Methods TEM, SEM and ATP efflux assay were used to evaluate the effect of hybrid peptides on the integrity of the pneumococcal cell wall/membrane. DNA retardation assay was assessed to measure the impact of hybrid peptides on the migration of genomic DNA through the agarose gel. In vitro synergistic effect was checked using the chequerboard assay. ICR male mice were used to evaluate the in vivo toxicity and antibacterial activity of the hybrid peptides in a standalone form and in combination with ceftriaxone. Results The results obtained from TEM and SEM indicated that the hybrid peptides caused significant morphological alterations in Streptococcus pneumoniae and disrupting the integrity of the cell wall/membrane. The rapid release of ATP from pneumococcal cells after one hour of incubation proposing that the antibacterial action for the hybrid peptides is based on membrane permeabilization and damage. The DNA retardation assay revealed that at 62.5 µg/ml all the hybrid peptides were capable of binding and preventing the pneumococcal genomic DNA from migrating through the agarose gel. In vitro synergy was observed when pneumococcal cells treated with combinations of hybrid peptides with each other and with conventional drugs erythromycin and ceftriaxone. The in vivo therapeutic efficacy results revealed that the hybrid peptide RN7-IN8 at 20 mg/kg could improve the survival rate of pneumococcal bacteremia infected mice, as 50% of the infected mice survived up to seven days post-infection. In vivo antibacterial efficacy of the hybrid peptide RN7-IN8 was signficantly improved when combined with the standard antibiotic ceftriaxone at (20 mg/kg + 20 mg/kg) as 100% of the infected mice survived up to seven days post-infection. Discussion Our results suggest that attacking and breaching the cell wall/membrane is most probably the principal mechanism for the hybrid peptides. In addition, the hybrid peptides could possess another mechanism of action by inhibiting intracellular functions such as DNA synthesis. AMPs could play a great role in combating antibiotic resistance as they can reduce the therapeutic concentrations of standard drugs. PMID:29018620

Near infrared optical biosensor based on peptide functionalized single-walled carbon nanotubes hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection.

PubMed

Wang, Jin

2018-06-01

A near infrared (NIR) optical biosensor based on peptide functionalized single-walled carbon nanotubes (SWCNTs) hybrids for 2,4,6-trinitrotoluene (TNT) explosive detection was developed. The TNT binding peptide was directly anchored on the sidewall of the SWCNTs using the π-π interaction between the aromatic amino acids and SWCNTs, forming the peptide-SWCNTs hybrids for near infrared absorption spectra measurement. The evidence of the morphology of peptide-SWCNTs hybrids was obtained using atomic force microscopy (AFM). The results demonstrated that peptide-SWCNTs hybrids based NIR optical biosensor exhibited sensitive and highly selective for TNT explosive determination, addressing a promising optical biosensor for security application. Copyright © 2018. Published by Elsevier Inc.

Strategies for designing novel functional meat products.

PubMed

Arihara, Keizo

2006-09-01

In recent years, much attention has been paid to physiological functions of foods due to increasing concerns for health. Although there has been limited information of physiological functions of meat until recently, several attractive meat-based bioactive compounds, such as carnosine, anserine, l-carnitine, conjugated linoleic acid, have been studied. Emphasizing these activities is one possible approach for improving the health image of meat and developing functional meat products. This article provides potential benefits of representative meat-based bioactive compounds on human health and an overview of meat-based functional products. Strategies for designing novel functional meat products utilizing bioactive peptides and/or probiotic bacteria, is also discussed. This article focuses particularly on the possibility of meat protein-derived bioactive peptides, such as antihypertensive peptides. There are still some hurdles in developing and marketing novel functional meat products since such products are unconventional and consumers in many countries recognize meat and meat products to be bad for health. Along with accumulation of scientific data, there is an urgent need to inform consumers of the exact functional value of meat and meat products including novel functional foods.

Peptidomics of prolyl endopeptidase in the central nervous system

PubMed Central

Nolte, Whitney M.; Tagore, Debarati M.; Lane, William S.; Saghatelian, Alan

2009-01-01

Prolyl endopeptidase (Prep) is a member of the prolyl peptidase family and is of interest due to its unique biochemistry and connections to cognitive function. Using an unbiased mass spectrometry (MS)-based peptidomics platform, we identified Prep regulated peptides in the central nervous system (CNS) of mice by measuring changes in the peptidome as a function of Prep activity. This approach was validated by the identification of known Prep substrates, such as the neuropeptide substance P and thymosin-β4, the precursor to the bioactive peptide Ac-SDKP. In addition to these known substrates, we also discovered that Prep regulates many additional peptides, including additional bioactive peptides and proline rich peptides (PRPs). Biochemical experiments confirmed that some of these Prep regulated peptides are indeed substrates of the enzyme. Moreover, these experiments also supported the known preference of Prep for shorter peptides, while revealing a previously unknown cleavage site specificity of Prep when processing certain multi-proline containing peptides, including PRPs. The discovery of Prep regulated peptides implicates Prep in new biological pathways and provides insights into the biochemistry of this enzyme. PMID:19911840

Mechanical stabilization of proteolytically degradable polyethylene glycol dimethacrylate hydrogels through peptide interaction.

PubMed

Lim, Hyun Ju; Khan, Zara; Lu, Xi; Perera, T Hiran; Wilems, Thomas S; Ravivarapu, Krishna T; Smith Callahan, Laura A

2018-04-15

Balancing enhancement of neurite extension against loss of matrix support in synthetic hydrogels containing proteolytically degradable and bioactive signaling peptides to optimize tissue formation is difficult. Using a systematic approach, polyethylene glycol hydrogels containing concurrent continuous concentration gradients of the laminin derived bioactive signaling peptide, Ile-Lys-Val-Ala-Val (IKVAV), and collagen derived matrix metalloprotease degradable peptide, GPQGIWGQ, were fabricated and characterized. During proteolytic degradation of the concentration gradient hydrogels, the IKVAV and IWGQ cleavage fragment from GPQGIWGQ were found to interact and stabilize the bulk Young's Modulus of the hydrogel. Further testing of discrete samples containing GPQGIWGQ or its cleavage fragments, GPQG and IWGQ, indicates hydrophobic interactions between the peptides are not necessary for mechanical stabilization of the hydrogel, but changes in the concentration ratio between the peptides tethered in the hydrogel and salts and ions in the swelling solution can affect the stabilization. Encapsulation of human induced pluripotent stem cell derived neural stem cells did not reduce the mechanical properties of the hydrogel over a 14 day neural differentiation culture period, and IKVAV was found to maintain concentration dependent effects on neurite extension and mRNA gene expression of neural cytoskeletal markers, similar to previous studies. As a result, this work has significant implications for the analysis of biological studies in matrices, as the material and mechanical properties of the hydrogel may be unexpectedly temporally changing during culture due to interactions between peptide signaling elements, underscoring the need for greater matrix characterization during the degradation and cell culture. Greater emulation of the native extracellular matrix is necessary for tissue formation. To achieve this, matrices are becoming more complex, often including multiple bioactive signaling elements. However, peptide signaling in polyethylene glycol matrices and amino acids interactions between peptides can affect hydrogel material and mechanical properties, but are rarely studied. The current study identifies such an interaction between laminin derived peptide, IKVAV, and collagen derived matrix metalloprotease degradable peptide, GPQGIWGQ. Previous studies using these peptides did not identify their interactions' ability to mechanically stabilize the hydrogel during degradation. This work underscores the need for greater matrix characterization and consideration of bioactive signaling element effects temporally on the matrix's material and mechanical properties, as they can contribute to cellular response. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Electrospun Polyhydroxybutyrate/Poly(ε-caprolactone)/58S Sol-Gel Bioactive Glass Hybrid Scaffolds with Highly Improved Osteogenic Potential for Bone Tissue Engineering.

PubMed

Ding, Yaping; Li, Wei; Müller, Teresa; Schubert, Dirk W; Boccaccini, Aldo R; Yao, Qingqing; Roether, Judith A

2016-07-13

Electrospinning of biopolymer and inorganic substances is one of the efficient ways to combine various advantageous properties in one single fibrous structure with potential for tissue engineering applications. In the present study, to integrate the high stiffness of polyhydroxybutyrate (PHB), the flexibility of poly(ε-caprolactone) (PCL) and the bioactivity of 58S bioactive glass, PHB/PCL/58S sol-gel bioactive glass hybrid scaffolds were fabricated using combined electrospinning and sol-gel method. Physical features such as fiber diameter distribution, mechanical strength and Young's modulus were characterized thoroughly. FTIR analysis demonstrated the successful incorporation of 58S bioactive glass into the blend polymers, which greatly improved the hydrophilicity of PHB/PCL fibermats. The primary biological response of MG-63 osteoblast-like cells on the prepared fibrous scaffolds was evaluated, proving that the 58S glass sol containing hybrid scaffold were not only favorable to MG-63 cell adhesion but also slightly enhanced cell viability and significantly increased alkaline phosphate activity .

Antifungal Activity and Action Mechanism of Histatin 5-Halocidin Hybrid Peptides against Candida ssp

PubMed Central

Han, Juhye; Jyoti, Md. Anirban; Song, Ho-Yeon; Jang, Woong Sik

2016-01-01

The candidacidal activity of histatin 5 is initiated through cell wall binding, followed by translocation and intracellular targeting, while the halocidin peptide exerts its activity by attacking the Candida cell membrane. To improve antimicrobial activities and to understand the killing mechanism of two peptides, six hybrid peptides were designed by conjugating histatin 5 and halocidin. A comparative approach was established to study the activity, salt tolerance, cell wall glucan binding assay, cytotoxicity, generation of ROS and killing kinetics. CD spectrometry was conducted to evaluate secondary structures of these hybrid peptides. Furthermore the cellular localization of hybrid peptides was investigated by confocal fluorescence microscopy. Of the six hybrid congeners, di-PH2, di-WP2 and HHP1 had stronger activities than other hybrid peptides against all tested Candida strains. The MIC values of these peptides were 1–2, 2–4 and 2–4 μg/ml, respectively. Moreover, none of the hybrid peptides was cytotoxic in the hemolytic assay and cell-based cytotoxicity assay. Confocal laser microscopy showed that di-PH2 and HHP1 were translocated into cytoplasm whereas di-WP2 was accumulated on surface of C. albicans to exert their candidacidal activity. All translocated peptides (Hst 5, P113, di-PH2) were capable of generating intracellular ROS except HHP1. Additionally, the KFH residues at C-terminal end of these peptides were assumed for core sequence for active translocation. PMID:26918792

Improving the bioactivity of bioglass/ (PMMA-co-MPMA) organic/inorganic hybrid.

PubMed

Ravarian, R; Wei, H; Dehghani, F

2011-01-01

Binary system of CaO-SiO(2) glasses enables the apatite formation in simulated body fluid (SBF). However, the presence of phosphate content in SiO(2)-CaO-P(2)O(5) glasses leads to the formation of orthophosphate nanocrystalline nuclei, which facilitates the generation of carbonate hydroxyapatite; this compound is more compatible with natural bone. The brittle and less flexible properties of bioactive glasses are the major obstacle for their application as bone implant. The hybridization of essential constituents of bioactive glasses and glass-ceramics with polymers such as PMMA can improve their poor mechanical properties. The aim of this study was to improve the bioactivity of nanocomposites fabricated from poly(methyl metacrylate) (PMMA) and bioglass for bone implant applications. Bioglass compounds with various phosphate contents were used for the preparation of PMMA/bioglass hybrid matrices. Since the lack of adhesion between the two phases impedes the homogenous composite formation, a silane coupling agent such as 3-(trimethoxysilyl)propyl methacrylates (MPMA) was incorporated into the polymer structure. The effect of addition of MPMA on the molecular structure of composite was investigated. Furthermore, the presence of MPMA in the system improved the homogeneity of sample. Increasing phosphate content in the inorganic segment of hybrid up to 10 mol% resulted in the formation of apatite layer on the surface; hence the hybrid was bioactive and suitable candidate for bone tissue engineering.

A new genome-mining tool redefines the lasso peptide biosynthetic landscape

PubMed Central

Tietz, Jonathan I.; Schwalen, Christopher J.; Patel, Parth S.; Maxson, Tucker; Blair, Patricia M.; Tai, Hua-Chia; Zakai, Uzma I.; Mitchell, Douglas A.

2016-01-01

Ribosomally synthesized and post-translationally modified peptide (RiPP) natural products are attractive for genome-driven discovery and re-engineering, but limitations in bioinformatic methods and exponentially increasing genomic data make large-scale mining difficult. We report RODEO (Rapid ORF Description and Evaluation Online), which combines hidden Markov model-based analysis, heuristic scoring, and machine learning to identify biosynthetic gene clusters and predict RiPP precursor peptides. We initially focused on lasso peptides, which display intriguing physiochemical properties and bioactivities, but their hypervariability renders them challenging prospects for automated mining. Our approach yielded the most comprehensive mapping of lasso peptide space, revealing >1,300 compounds. We characterized the structures and bioactivities of six lasso peptides, prioritized based on predicted structural novelty, including an unprecedented handcuff-like topology and another with a citrulline modification exceptionally rare among bacteria. These combined insights significantly expand the knowledge of lasso peptides, and more broadly, provide a framework for future genome-mining efforts. PMID:28244986

Isolation, purification and characterization of antioxidative peptide of pearl millet (Pennisetum glaucum) protein hydrolysate.

PubMed

Agrawal, Himani; Joshi, Robin; Gupta, Mahesh

2016-08-01

Pearl millet (Pennisetum glaucum) is a rich source of protein, used for present study to hydrolyze protein, peptide separation and its functional activity. Antioxidative bioactive peptide was successfully identified from pearl millet using trypsin enzyme. Different antioxidative potential of isolated peptide were assessed based on activity of DPPH radical, ABTS radical, hydroxyl radical, Fe(2+) chelating ability and reducing power. Bioactive peptide separated by gel-filtration chromatography, showed the higher antioxidant activity as tested by different free radicals. The activity of pearl millet protein hydrolysate fraction was found for DPPH assay (67.66%), ABTS assay (78.81%), Fe(2+) chelating ability (51.20%), hydroxyl assay (60.95%) and reducing power (0.375nm) was further purified using reversed-phase UFLC and subjected to matrix assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF-MS) for sequential identification of the peptide. The sequence SDRDLLGPNNQYLPK was identified as antioxidant peptide. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioactive Molecule-loaded Drug Delivery Systems to Optimize Bone Tissue Repair.

PubMed

Oshiro, Joao Augusto; Sato, Mariana Rillo; Scardueli, Cassio Rocha; Lopes de Oliveira, Guilherme Jose Pimentel; Abucafy, Marina Paiva; Chorilli, Marlus

2017-01-01

Bioactive molecules such as peptides and proteins can optimize the repair of bone tissue; however, the results are often unpredictable when administered alone, owing to their short biological half-life and instability. Thus, the development of bioactive molecule-loaded drug delivery systems (DDS) to repair bone tissue has been the subject of intense research. DDS can optimize the repair of bone tissue owing to their physicochemical properties, which improve cellular interactions and enable the incorporation and prolonged release of bioactive molecules. These characteristics are fundamental to favor bone tissue homeostasis, since the biological activity of these factors depends on how accessible they are to the cell. Considering the importance of these DDS, this review aims to present relevant information on DDS when loaded with osteogenic growth peptide and bone morphogenetic protein. These are bioactive molecules that are capable of modulating the differentiation and proliferation of mesenchymal cells in bone tissue cells. Moreover, we will present different approaches using these peptide and protein-loaded DDS, such as synthetic membranes and scaffolds for bone regeneration, synthetic grafts, bone cements, liposomes, and micelles, which aim at improving the therapeutic effectiveness, and we will compare their advantages with commercial systems. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dual peptide-mediated targeted delivery of bioactive siRNAs to oral cancer cells in vivo.

PubMed

Alexander-Bryant, Angela A; Zhang, Haiwen; Attaway, Christopher C; Pugh, William; Eggart, Laurence; Sansevere, Robert M; Andino, Lourdes M; Dinh, Lu; Cantini, Liliana P; Jakymiw, Andrew

2017-09-01

Despite significant advances in cancer treatment, the prognosis for oral cancer remains poor in comparison to other cancer types, including breast, skin, and prostate. As a result, more effective therapeutic modalities are needed for the treatment of oral cancer. Consequently, in the present study, we examined the feasibility of using a dual peptide carrier approach, combining an epidermal growth factor receptor (EGFR)-targeting peptide with an endosome-disruptive peptide, to mediate targeted delivery of small interfering RNAs (siRNAs) into EGFR-overexpressing oral cancer cells and induce silencing of the targeted oncogene, cancerous inhibitor of protein phosphatase 2A (CIP2A). Fluorescence microscopy, real-time PCR, Western blot analysis, and in vivo bioimaging of mice containing orthotopic xenograft tumors were used to examine the ability of the dual peptide carrier to mediate specific delivery of bioactive siRNAs into EGFR-overexpressing oral cancer cells/tissues. Co-complexation of the EGFR-targeting peptide, GE11R9, with the endosome-disruptive 599 peptide facilitated the specific uptake of siRNAs into oral cancer cells overexpressing EGFR in vitro with optimal gene silencing observed at a 60:30:1 (GE11R9:599:siRNA) molar ratio. Furthermore, when administered systemically to mice bearing xenograft oral tumors, this dual peptide complex mediated increased targeted delivery of siRNAs into tumor tissues in comparison to the 599 peptide alone and significantly enhanced CIP2A silencing. Herein we provide the first report demonstrating the clinical potential of a dual peptide strategy for siRNA-based therapeutics by synergistically mediating the effective targeting and delivery of bioactive siRNAs into EGFR-overexpressing oral cancer cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bioactive Peptides in Animal Food Products.

PubMed

Albenzio, Marzia; Santillo, Antonella; Caroprese, Mariangela; Della Malva, Antonella; Marino, Rosaria

2017-05-09

Proteins of animal origin represent physiologically active components in the human diet; they exert a direct action or constitute a substrate for enzymatic hydrolysis upon food processing and consumption. Bioactive peptides may descend from the hydrolysis by digestive enzymes, enzymes endogenous to raw food materials, and enzymes from microorganisms added during food processing. Milk proteins have different polymorphisms for each dairy species that influence the amount and the biochemical characteristics (e.g., amino acid chain, phosphorylation, and glycosylation) of the protein. Milk from other species alternative to cow has been exploited for their role in children with cow milk allergy and in some infant pathologies, such as epilepsy, by monitoring the immune status. Different mechanisms concur for bioactive peptides generation from meat and meat products, and their functionality and application as functional ingredients have proven effects on consumer health. Animal food proteins are currently the main source of a range of biologically-active peptides which have gained special interest because they may also influence numerous physiological responses in the organism. The addition of probiotics to animal food products represent a strategy for the increase of molecules with health and functional properties.

Rapid screening and identification of ACE inhibitors in snake venoms using at-line nanofractionation LC-MS.

PubMed

Mladic, Marija; de Waal, Tessa; Burggraaff, Lindsey; Slagboom, Julien; Somsen, Govert W; Niessen, Wilfried M A; Manjunatha Kini, R; Kool, Jeroen

2017-10-01

This study presents an analytical method for the screening of snake venoms for inhibitors of the angiotensin-converting enzyme (ACE) and a strategy for their rapid identification. The method is based on an at-line nanofractionation approach, which combines liquid chromatography (LC), mass spectrometry (MS), and pharmacology in one platform. After initial LC separation of a crude venom, a post-column flow split is introduced enabling parallel MS identification and high-resolution fractionation onto 384-well plates. The plates are subsequently freeze-dried and used in a fluorescence-based ACE activity assay to determine the ability of the nanofractions to inhibit ACE activity. Once the bioactive wells are identified, the parallel MS data reveals the masses corresponding to the activities found. Narrowing down of possible bioactive candidates is provided by comparison of bioactivity profiles after reversed-phase liquid chromatography (RPLC) and after hydrophilic interaction chromatography (HILIC) of a crude venom. Additional nanoLC-MS/MS analysis is performed on the content of the bioactive nanofractions to determine peptide sequences. The method described was optimized, evaluated, and successfully applied for screening of 30 snake venoms for the presence of ACE inhibitors. As a result, two new bioactive peptides were identified: pELWPRPHVPP in Crotalus viridis viridis venom with IC 50  = 1.1 μM and pEWPPWPPRPPIPP in Cerastes cerastes cerastes venom with IC 50  = 3.5 μM. The identified peptides possess a high sequence similarity to other bradykinin-potentiating peptides (BPPs), which are known ACE inhibitors found in snake venoms.

Structural Interplay - Tuning Mechanics in Peptide-Polyurea Hybrids

NASA Astrophysics Data System (ADS)

Korley, Lashanda

Utilizing cues from natural materials, we have been inspired to explore the hierarchical arrangement critical to energy absorption and mechanical enhancement in synthetic systems. Of particular interest is the soft domain ordering proposed as a contributing element to the observed toughness in spider silk. Multiblock copolymers, are ideal and dynamic systems in which to explore this approach via variations in secondary structure of nature's building blocks - peptides. We have designed a new class of polyurea hybrids that incorporate peptidic copolymers as the soft segment. The impact of hierarchical ordering on the thermal, mechanical, and morphological behavior of these bio-inspired polyurethanes with a siloxane-based, peptide soft segment was investigated. These peptide-polyurethane/urea hybrids were microphase segregated, and the beta-sheet secondary structure of the soft segment was preserved during polymerization and film casting. Toughness enhancement at low strains was achieved, but the overall extensibility of the peptide-incorporated systems was reduced due to the unique hard domain organization. To decouple the secondary structure influence in the siloxane-peptide soft segment from mechanics dominated by the hard domain, we also developed non-chain extended peptide-polyurea hybrids in which the secondary structure (beta sheet vs. alpha helix) was tuned via choice of peptide and peptide length. It was shown that this structural approach allowed tailoring of extensibility, toughness, and modulus. The sheet-dominant hybrid materials were typically tougher and more elastic due to intermolecular H-bonding facilitating load distribution, while the helical-prevalent systems generally exhibited higher stiffness. Recently, we have explored the impact of a molecular design strategy that overlays a covalent and physically crosslinked architecture in these peptide-polyurea hybrids, demonstrating that physical constraints in the network hybrids influences peptide hydrogen bonding and morphology. These structural features correlated well with systematic changes in modulus, extensibility, and hysteresis. Complementary to this effort is the design of PEG-based peptide-polyurea hybrids with tunable and responsive as structural and injectable hydrogels. The authors acknowledge funding support from the National Science Foundation (CAREER DMR-0953236).

Concentration dependent survival and neural differentiation of murine embryonic stem cells cultured on polyethylene glycol dimethacrylate hydrogels possessing a continuous concentration gradient of n-cadherin derived peptide His-Ala-Val-Asp-Lle.

PubMed

Lim, Hyun Ju; Mosley, Matthew C; Kurosu, Yuki; Smith Callahan, Laura A

2017-07-01

N-cadherin cell-cell signaling plays a key role in the structure and function of the nervous system. However, few studies have incorporated bioactive signaling from n-cadherin into tissue engineering matrices. The present study uses a continuous gradient approach in polyethylene glycol dimethacrylate hydrogels to identify concentration dependent effects of n-cadherin peptide, His-Ala-Val-Asp-Lle (HAVDI), on murine embryonic stem cell survival and neural differentiation. The n-cadherin peptide was found to affect the expression of pluripotency marker, alkaline phosphatase, in murine embryonic stem cells cultured on n-cadherin peptide containing hydrogels in a concentration dependent manner. Increasing n-cadherin peptide concentrations in the hydrogels elicited a biphasic response in neurite extension length and mRNA expression of neural differentiation marker, neuron-specific class III β-tubulin, in murine embryonic stem cells cultured on the hydrogels. High concentrations of n-cadherin peptide in the hydrogels were found to increase the expression of apoptotic marker, caspase 3/7, in murine embryonic stem cells compared to that of murine embryonic stem cell cultures on hydrogels containing lower concentrations of n-cadherin peptide. Increasing the n-cadherin peptide concentration in the hydrogels facilitated greater survival of murine embryonic stem cells exposed to increasing oxidative stress caused by hydrogen peroxide exposure. The combinatorial approach presented in this work demonstrates concentration dependent effects of n-cadherin signaling on mouse embryonic stem cell behavior, underscoring the need for the greater use of systematic approaches in tissue engineering matrix design in order to understand and optimize bioactive signaling in the matrix for tissue formation. Single cell encapsulation is common in tissue engineering matrices. This eliminates cellular access to cell-cell signaling. N-cadherin, a cell-cell signaling molecule, plays a vital role in the development of neural tissues, but has not been well studied as a bioactive signaling element in neural tissue engineering matrices. The present study uses a systematic continuous gradient approach to identify concentration dependent effects of n-cadherin derived peptide, HAVDI, on the survival and neural differentiation of murine embryonic stem cells. This work underscores the need for greater use to combinatorial strategies to understand the effect complex bioactive signaling, such as n-cadherin, and the need to optimize the concentration of such bioactive signaling within tissue engineering matrices for maximal cellular response. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Screening of bioactive peptides using an embryonic stem cell-based neurodifferentiation assay.

PubMed

Xu, Ruodan; Feyeux, Maxime; Julien, Stéphanie; Nemes, Csilla; Albrechtsen, Morten; Dinnyés, Andras; Krause, Karl-Heinz

2014-05-01

Differentiation of pluripotent stem cells, PSCs, towards neural lineages has attracted significant attention, given the potential use of such cells for in vitro studies and for regenerative medicine. The present experiments were designed to identify bioactive peptides which direct PSC differentiation towards neural cells. Fifteen peptides were designed based on NCAM, FGFR, and growth factors sequences. The effect of peptides was screened using a mouse embryonic stem cell line expressing luciferase dual reporter construct driven by promoters for neural tubulin and for elongation factor 1. Cell number was estimated by measuring total cellular DNA. We identified five peptides which enhanced activities of both promoters without relevant changes in cell number. We selected the two most potent peptides for further analysis: the NCAM-derived mimetic FGLL and the synthetic NCAM ligand, Plannexin. Both compounds induced phenotypic neuronal differentiation, as evidenced by increased neurite outgrowth. In summary, we used a simple, but sensitive screening approach to identify the neurogenic peptides. These peptides will not only provide new clues concerning pathways of neurogenesis, but they may also be interesting biotechnology tools for in vitro generation of neurons.

Recent insights in the use of nanocarriers for the oral delivery of bioactive proteins and peptides.

PubMed

Batista, Patrícia; Castro, Pedro M; Madureira, Ana Raquel; Sarmento, Bruno; Pintado, Manuela

2018-03-01

Bioactive proteins and peptides have been used with either prophylactic or therapeutic purposes, presenting inherent advantages as high specificity and biocompatibility. Nanocarriers play an important role in the stabilization of proteins and peptides, offering enhanced buccal permeation and protection while crossing the gastrointestinal tract. Moreover, preparation of nanoparticles as oral delivery systems for proteins/peptides may include tailored formulation along with functionalization aiming bioavailability enhancement of carried proteins or peptides. Oral delivery systems, namely buccal delivery systems, represent an interesting alternative route to parenteric delivery systems to carry proteins and peptides, resulting in higher comfort of administration and, therefore, compliance to treatment. This paper outlines an extensive overview of the existing publications on proteins/peptides oral nanocarriers delivery systems, with special focus on buccal route. Manufacturing aspects of most commonly used nanoparticles for oral delivery (e.g. polymeric nanoparticles using synthetic or natural polymers and lipid nanoparticles) advantages and limitations and potential applications of nanoparticles as proteins/peptides delivery systems will also be thoroughly addressed. Copyright © 2018 Elsevier Inc. All rights reserved.

Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate.

PubMed

Kent, R M; Guinane, C M; O'Connor, P M; Fitzgerald, G F; Hill, C; Stanton, C; Ross, R P

2012-08-01

The aim of this study was to identify Bacillus isolates capable of degrading sodium caseinate and subsequently to generate bioactive peptides with antimicrobial activity. Sodium caseinate (2.5% w/v) was inoculated separately with 16 Bacillus isolates and allowed to ferment overnight. Protein breakdown in the fermentates was analysed using gel permeation-HPLC (GP-HPLC) and screened for peptides (<3-kDa) with MALDI-TOF mass spectrometry. Caseicin A (IKHQGLPQE) and caseicin B (VLNENLLR), two previously characterized antimicrobial peptides, were identified in the fermentates of both Bacillus cereus and Bacillus thuringiensis isolates. The caseicin peptides were subsequently purified by RP-HPLC and antimicrobial assays indicated that the peptides maintained the previously identified inhibitory activity against the infant formula pathogen Cronobacter sakazakii. We report a new method using Bacillus sp. to generate two previously characterized antimicrobial peptides from casein. This study highlights the potential to exploit Bacillus sp. or the enzymes they produce for the generation of bioactive antimicrobial peptides from bovine casein. © 2012 The Authors. Letters in Applied Microbiology © 2012 The Society for Applied Microbiology.

Mung bean proteins and peptides: nutritional, functional and bioactive properties.

PubMed

Yi-Shen, Zhu; Shuai, Sun; FitzGerald, Richard

2018-01-01

To date, no extensive literature review exists regarding potential uses of mung bean proteins and peptides. As mung bean has long been widely used as a food source, early studies evaluated mung bean nutritional value against the Food and Agriculture Organization of the United Nations (FAO)/the World Health Organization (WHO) amino acids dietary recommendations. The comparison demonstrated mung bean to be a good protein source, except for deficiencies in sulphur-containing amino acids, methionine and cysteine. Methionine and cysteine residues have been introduced into the 8S globulin through protein engineering technology. Subsequently, purified mung bean proteins and peptides have facilitated the study of their structural and functional properties. Two main types of extraction methods have been reported for isolation of proteins and peptides from mung bean flours, permitting sequencing of major proteins present in mung bean, including albumins and globulins (notably 8S globulin). However, the sequence for albumin deposited in the UniProt database differs from other sequences reported in the literature. Meanwhile, a limited number of reports have revealed other useful bioactivities for proteins and hydrolysed peptides, including angiotensin-converting enzyme inhibitory activity, anti-fungal activity and trypsin inhibitory activity. Consequently, several mung bean hydrolysed peptides have served as effective food additives to prevent proteolysis during storage. Ultimately, further research will reveal other nutritional, functional and bioactive properties of mung bean for uses in diverse applications.

Mung bean proteins and peptides: nutritional, functional and bioactive properties

PubMed Central

Yi-Shen, Zhu; Shuai, Sun; FitzGerald, Richard

2018-01-01

To date, no extensive literature review exists regarding potential uses of mung bean proteins and peptides. As mung bean has long been widely used as a food source, early studies evaluated mung bean nutritional value against the Food and Agriculture Organization of the United Nations (FAO)/the World Health Organization (WHO) amino acids dietary recommendations. The comparison demonstrated mung bean to be a good protein source, except for deficiencies in sulphur-containing amino acids, methionine and cysteine. Methionine and cysteine residues have been introduced into the 8S globulin through protein engineering technology. Subsequently, purified mung bean proteins and peptides have facilitated the study of their structural and functional properties. Two main types of extraction methods have been reported for isolation of proteins and peptides from mung bean flours, permitting sequencing of major proteins present in mung bean, including albumins and globulins (notably 8S globulin). However, the sequence for albumin deposited in the UniProt database differs from other sequences reported in the literature. Meanwhile, a limited number of reports have revealed other useful bioactivities for proteins and hydrolysed peptides, including angiotensin-converting enzyme inhibitory activity, anti-fungal activity and trypsin inhibitory activity. Consequently, several mung bean hydrolysed peptides have served as effective food additives to prevent proteolysis during storage. Ultimately, further research will reveal other nutritional, functional and bioactive properties of mung bean for uses in diverse applications. PMID:29545737

Encapsulation, protection, and delivery of bioactive proteins and peptides using nanoparticle and microparticle systems: A review.

PubMed

McClements, David Julian

2018-03-01

There are many examples of bioactive proteins and peptides that would benefit from oral delivery through functional foods, supplements, or medical foods, including hormones, enzymes, antimicrobials, vaccines, and ACE inhibitors. However, many of these bioactive proteins are highly susceptible to denaturation, aggregation or hydrolysis within commercial products or inside the human gastrointestinal tract (GIT). Moreover, many bioactive proteins have poor absorption characteristics within the GIT. Colloidal systems, which contain nanoparticles or microparticles, can be designed to encapsulate, retain, protect, and deliver bioactive proteins. For instance, a bioactive protein may have to remain encapsulated and stable during storage and passage through the mouth and stomach, but then be released within the small intestine where it can be absorbed. This article reviews the application of food-grade colloidal systems for oral delivery of bioactive proteins, including microemulsions, emulsions, nanoemulsions, solid lipid nanoparticles, multiple emulsions, liposomes, and microgels. It also provides a critical assessment of the characteristics of colloidal particles that impact the effectiveness of protein delivery systems, such as particle composition, size, permeability, interfacial properties, and stability. This information should be useful for the rational design of medical foods, functional foods, and supplements for effective oral delivery of bioactive proteins. Copyright © 2018 Elsevier B.V. All rights reserved.

Gastrointestinal Endogenous Protein-Derived Bioactive Peptides: An in Vitro Study of Their Gut Modulatory Potential

PubMed Central

Dave, Lakshmi A.; Hayes, Maria; Mora, Leticia; Montoya, Carlos A.; Moughan, Paul J.; Rutherfurd, Shane M.

2016-01-01

A recently proposed paradigm suggests that, like their dietary counterparts, digestion of gastrointestinal endogenous proteins (GEP) may also produce bioactive peptides. With an aim to test this hypothesis, in vitro digests of four GEP namely; trypsin (TRYP), lysozyme (LYS), mucin (MUC), serum albumin (SA) and a dietary protein chicken albumin (CA) were screened for their angiotensin-I converting (ACE-I), renin, platelet-activating factor-acetylhydrolase (PAF-AH) and dipeptidyl peptidase-IV inhibitory (DPP-IV) and antioxidant potential following simulated in vitro gastrointestinal digestion. Further, the resultant small intestinal digests were enriched to obtain peptides between 3–10 kDa in size. All in vitro digests of the four GEP were found to inhibit ACE-I compared to the positive control captopril when assayed at a concentration of 1 mg/mL, while the LYS < 3-kDa permeate fraction inhibited renin by 40% (±1.79%). The LYS < 10-kDa fraction inhibited PAF-AH by 39% (±4.34%), and the SA < 3-kDa fraction inhibited DPP-IV by 45% (±1.24%). The MUC < 3-kDa fraction had an ABTS-inhibition antioxidant activity of 150 (±24.79) µM trolox equivalent and the LYS < 10-kDa fraction inhibited 2,2-Diphenyl-1-picrylhydrazyl (DPPH) by 54% (±1.62%). Moreover, over 190 peptide-sequences were identified from the bioactive GEP fractions. The findings of the present study indicate that GEP are a significant source of bioactive peptides which may influence gut function. PMID:27043546

Simultaneous Delivery of Highly Diverse Bioactive Compounds from Blend Electrospun Fibers for Skin Wound Healing.

PubMed

Peh, Priscilla; Lim, Natalie Sheng Jie; Blocki, Anna; Chee, Stella Min Ling; Park, Heyjin Chris; Liao, Susan; Chan, Casey; Raghunath, Michael

2015-07-15

Blend emulsion electrospinning is widely perceived to destroy the bioactivity of proteins, and a blend emulsion of water-soluble and nonsoluble molecules is believed to be thermodynamically unstable to electrospin smoothly. Here we demonstrate a method to retain the bioactivity of disparate fragile biomolecules when electrospun. Using bovine serum albumin as a carrier protein; water-soluble vitamin C, fat soluble vitamin D3, steroid hormone hydrocortisone, peptide hormone insulin, thyroid hormone triiodothyronine (T3), and peptide epidermal growth factor (EGF) were simultaneously blend-spun into PLGA-collagen nanofibers. Upon release, vitamin C maintained the ability to facilitate Type I collagen secretion by fibroblasts, EGF stimulated skin fibroblast proliferation, and insulin potentiated adipogenic differentiation. Transgenic cell reporter assays confirmed the bioactivity of vitamin D3, T3, and hydrocortisone. These factors concertedly increased keratinocyte and fibroblast proliferation while maintaining keratinocyte basal state. This method presents an elegant solution to simultaneously deliver disparate bioactive biomolecules for wound healing applications.

Using the peptide BP100 as a cell-penetrating tool for the chemical engineering of actin filaments within living plant cells.

PubMed

Eggenberger, Kai; Mink, Christian; Wadhwani, Parvesh; Ulrich, Anne S; Nick, Peter

2011-01-03

The delivery of externally applied macromolecules or nanoparticles into living cells still represents a critically limiting step before the full capabilities of chemical engineering can be explored. Molecular transporters such as cell-penetrating peptides, peptoids, and other mimetics can be used to carry cargo across the cellular membrane, but it is still difficult to find suitable sequences that operate efficiently for any particular type of cell. Here we report that BP100 (KKLFKKILKYL-amide), originally designed as an antimicrobial peptide against plant pathogens, can be employed as a fast and efficient cell-penetrating agent to transport fluorescent test cargoes into the cytosol of walled plant cells. The uptake of BP100 proceeds slightly more slowly than the endocytosis of fluorescent dextranes, but BP100 accumulates more efficiently and to much higher levels (by an order of magnitude). The entry of BP100 can be efficiently blocked by latrunculin B; this suggests that actin filaments are essential to the uptake mechanism. To test whether this novel transporter can also be used to deliver functional cargoes, we designed a fusion construct of BP100 with the actin-binding Lifeact peptide (MGVADLIKKFESISKEE). We demonstrated that the short BP100 could transport the attached 17-residue sequence quickly and efficiently into tobacco cells. The Lifeact construct retained its functionality as it successfully labeled the actin bundles that tether the nucleus in the cell center.

Use of phytochemomics to evaluate the bioavailability and bioactivity of antioxidant peptides of soybean β-conglycinin.

PubMed

Amigo-Benavent, Miryam; Clemente, Alfonso; Caira, Simonetta; Stiuso, Paola; Ferranti, Pasquale; del Castillo, M Dolores

2014-06-01

This research investigates how in vitro digestion contributes to the release of antioxidant peptides crypted in soybean β-conglycinin (7S) and its deglycosylated form (D7S). It also investigates the uptake of the bioactive peptides by human intestinal Caco-2 cells using a bicameral system, and their effect on the antioxidant cell defense. Phytochemomics is used as a tool for achieving this goal. The peptides are obtained by mimicking human physiological gastrointestinal digestion conditions. The antioxidant capacity of the peptides is tested by ABTS•(+) radical cation decolorization (2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS)) and oxygen radical absorbance capacity assays. The antioxidant power of the peptides recovered from the basolateral chamber is also evaluated by an analysis of biomarkers of cellular oxidative stress such as cell proliferation, alkaline phosphatase, and secretion of nitric oxide, lipid peroxidation, superoxide dismutase and catalase. Peptides from D7S were more active than those of 7S in the modulation of the cell proliferation, oxidative status and differentiation of Caco-2 cells treated with H2 O2 . Differences in the bioactivity of the peptides of both proteins can be explained by analysis of the structural data obtained by mass spectrophotometry. Our findings support the bioavailability of antioxidant peptides of 7S. The antioxidant properties of 7S soy protein were influenced by events such as glycosylation, digestion, and absorption. Deglycosylation seems to be an innovative strategy for improving the properties of 7S. Deglycosylation might enhance 7S antioxidant power and reduce its immunoreactivity. The combined use of advanced analytical techniques and biochemical analyses (phytochemomics) has been a key part of this study. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Attractors in Sequence Space: Agent-Based Exploration of MHC I Binding Peptides.

PubMed

Jäger, Natalie; Wisniewska, Joanna M; Hiss, Jan A; Freier, Anja; Losch, Florian O; Walden, Peter; Wrede, Paul; Schneider, Gisbert

2010-01-12

Ant Colony Optimization (ACO) is a meta-heuristic that utilizes a computational analogue of ant trail pheromones to solve combinatorial optimization problems. The size of the ant colony and the representation of the ants' pheromone trails is unique referring to the given optimization problem. In the present study, we employed ACO to generate novel peptides that stabilize MHC I protein on the plasma membrane of a murine lymphoma cell line. A jury of feedforward neural network classifiers served as fitness function for peptide design by ACO. Bioactive murine MHC I H-2K(b) stabilizing as well as nonstabilizing octapeptides were designed, synthesized and tested. These peptides reveal residue motifs that are relevant for MHC I receptor binding. We demonstrate how the performance of the implemented ACO algorithm depends on the colony size and the size of the search space. The actual peptide design process by ACO constitutes a search path in sequence space that can be visualized as trajectories on a self-organizing map (SOM). By projecting the sequence space on a SOM we visualize the convergence of the different solutions that emerge during the optimization process in sequence space. The SOM representation reveals attractors in sequence space for MHC I binding peptides. The combination of ACO and SOM enables systematic peptide optimization. This technique allows for the rational design of various types of bioactive peptides with minimal experimental effort. Here, we demonstrate its successful application to the design of MHC-I binding and nonbinding peptides which exhibit substantial bioactivity in a cell-based assay. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Purification of a peptide from seahorse, that inhibits TPA-induced MMP, iNOS and COX-2 expression through MAPK and NF-kappaB activation, and induces human osteoblastic and chondrocytic differentiation.

PubMed

Ryu, BoMi; Qian, Zhong-Ji; Kim, Se-Kwon

2010-03-30

Ongoing efforts to search for naturally occurring, bioactive substances for the amelioration of arthritis have led to the discovery of natural products with substantial bioactive properties. The seahorse (Hippocampus kuda Bleeler), a telelost fish, is one source of known beneficial products, yet has not been utilized for arthritis research. In the present work, we have purified and characterized a bioactive peptide from seahorse hydrolysis. Among the hydrolysates tested, pronase E-derived hydrolysate exhibited the highest alkaline phosphatase (ALP) activity, a phenotype marker of osteoblast and chondrocyte differentiation. After its separation from the hydrolysate by several purification steps, the peptide responsible for the ALP activity was isolated and its sequence was identified as LEDPFDKDDWDNWK (1821Da). We have shown that the isolated peptide induces differentiation of osteoblastic MG-63 and chondrocytic SW-1353 cells by measuring ALP activity, mineralization and collagen synthesis. Our results indicate that the peptide acts during early to late stages of differentiation in MG-63 and SW-1353 cells. We also assessed the concentration dependence of the peptide's inhibition of MMP (-1, -3 and -13), iNOS and COX-2 expression after treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA), a common form of phorbol ester. The peptide also inhibited NO production in MG-63 and SW-1353 cells. To elucidate the mechanisms by which the peptide acted, we examined its effects on TPA-induced MAPKs/NF-kappaB activation and determined that the peptide treatment significantly reduced p38 kinase/NF-kappaB in MG-63 cells and MAPKs/NF-kappaB in SW-1353 cells.

Impact of ultrafiltration and nanofiltration of an industrial fish protein hydrolysate on its bioactive properties.

PubMed

Picot, Laurent; Ravallec, Rozenn; Fouchereau-Péron, Martine; Vandanjon, Laurent; Jaouen, Pascal; Chaplain-Derouiniot, Maryse; Guérard, Fabienne; Chabeaud, Aurélie; Legal, Yves; Alvarez, Oscar Martinez; Bergé, Jean-Pascal; Piot, Jean-Marie; Batista, Irineu; Pires, Carla; Thorkelsson, Gudjon; Delannoy, Charles; Jakobsen, Greta; Johansson, Inez; Bourseau, Patrick

2010-08-30

Numerous studies have demonstrated that in vitro controlled enzymatic hydrolysis of fish and shellfish proteins leads to bioactive peptides. Ultrafiltration (UF) and/or nanofiltration (NF) can be used to refine hydrolysates and also to fractionate them in order to obtain a peptide population enriched in selected sizes. This study was designed to highlight the impact of controlled UF and NF on the stability of biological activities of an industrial fish protein hydrolysate (FPH) and to understand whether fractionation could improve its content in bioactive peptides. The starting fish protein hydrolysate exhibited a balanced amino acid composition, a reproducible molecular weight (MW) profile, and a low sodium chloride content, allowing the study of its biological activity. Successive fractionation on UF and NF membranes allowed concentration of peptides of selected sizes, without, however, carrying out sharp separations, some MW classes being found in several fractions. Peptides containing Pro, Hyp, Asp and Glu were concentrated in the UF and NF retentates compared to the unfractionated hydrolysate and UF permeate, respectively. Gastrin/cholecystokinin-like peptides were present in the starting FPH, UF and NF fractions, but fractionation did not increase their concentration. In contrast, quantification of calcitonin gene-related peptide (CGRP)-like peptides demonstrated an increase in CGRP-like activities in the UF permeate, relative to the starting FPH. The starting hydrolysate also showed a potent antioxidant and radical scavenging activity, and a moderate angiotensin-converting enzyme (ACE)-1 inhibitory activity, which were not increased by UF and NF fractionation. Fractionation of an FPH using membrane separation, with a molecular weight cut-off adapted to the peptide composition, may provide an effective means to concentrate CGRP-like peptides and peptides enriched in selected amino acids. The peptide size distribution observed after UF and NF fractionation demonstrates that it is misleading to characterize the fractions obtained by membrane filtration according to the MW cut-off of the membrane only, as is currently done in the literature. Copyright (c) 2010 Society of Chemical Industry.

Bioactive Compounds in Functional Meat Products.

PubMed

Pogorzelska-Nowicka, Ewelina; Atanasov, Atanas G; Horbańczuk, Jarosław; Wierzbicka, Agnieszka

2018-01-31

Meat and meat products are a good source of bioactive compounds with positive effect on human health such as vitamins, minerals, peptides or fatty acids. Growing food consumer awareness and intensified global meat producers competition puts pressure on creating new healthier meat products. In order to meet these expectations, producers use supplements with functional properties for animal diet and as direct additives for meat products. In the presented work seven groups of key functional constituents were chosen: (i) fatty acids; (ii) minerals; (iii) vitamins; (iv) plant antioxidants; (v) dietary fibers; (vi) probiotics and (vii) bioactive peptides. Each of them is discussed in term of their impact on human health as well as some quality attributes of the final products.

High Specific Selectivity and Membrane-Active Mechanism of Synthetic Cationic Hybrid Antimicrobial Peptides Based on the Peptide FV7

PubMed Central

Tan, Tingting; Wu, Di; Li, Weizhong; Zheng, Xin; Li, Weifen; Shan, Anshan

2017-01-01

Hybrid peptides integrating different functional domains of peptides have many advantages, such as remarkable antimicrobial activity, lower hemolysis and ideal cell selectivity, compared with natural antimicrobial peptides. FV7 (FRIRVRV-NH2), a consensus amphiphilic sequence was identified as being analogous to host defense peptides. In this study, we designed a series of hybrid peptides FV7-LL-37 (17–29) (FV-LL), FV7-magainin 2 (9–21) (FV-MA) and FV7-cecropin A (1–8) (FV-CE) by combining the FV7 sequence with the small functional sequences LL-37 (17–29) (LL), magainin 2 (9–21) (MA) and cecropin A (1–8) (CE) which all come from well-described natural peptides. The results demonstrated that the synthetic hybrid peptides, in particular FV-LL, had potent antibacterial activities over a wide range of Gram-negative and Gram-positive bacteria with lower hemolytic activity than other peptides. Furthermore, fluorescent spectroscopy indicated that the hybrid peptide FV-LL exhibited marked membrane destruction by inducing outer and inner bacterial membrane permeabilization, while scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that FV-LL damaged membrane integrity by disrupting the bacterial membrane. Inhibiting biofilm formation assays also showed that FV-LL had similar anti-biofilm activity compared with the functional peptide sequence FV7. Synthetic cationic hybrid peptides based on FV7 could provide new models for combining different functional domains and demonstrate effective avenues to screen for novel antimicrobial agents. PMID:28178190

A review of fish-derived antioxidant and antimicrobial peptides: their production, assessment, and applications.

PubMed

Najafian, L; Babji, A S

2012-01-01

Fishes are rich sources of structurally diverse bioactive compounds. In recent years, much attention has been paid to the existence of peptides with biological activities and proteins derived from foods that might have beneficial effects for humans. Antioxidant and antimicrobial peptides isolated from fish sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This paper presents an overview of the antioxidant and antimicrobial peptides derived from various fishes. In addition, we discuss the extraction of fish proteins, enzymatic production, and the techniques used to isolate and characterize these compounds. Furthermore, we review the methods used to assay the bioactivities and their applications in food and nutraceuticals. Copyright © 2011 Elsevier Inc. All rights reserved.

Co-immobilization of active antibiotics and cell adhesion peptides on calcium based biomaterials.

PubMed

Palchesko, Rachelle N; Buckholtz, Gavin A; Romeo, Jared D; Gawalt, Ellen S

2014-07-01

Two bioactive molecules with unrelated functions, vancomycin and a cell adhesion peptide, were immobilized on the surface of a potential bone scaffold material, calcium aluminum oxide. In order to accomplish immobilization and retain bioactivity three sequential surface functionalization strategies were compared: 1.) vancomycin was chemically immobilized before a cell adhesion peptide (KRSR), 2.) vancomycin was chemically immobilized after KRSR and 3.) vancomycin was adsorbed after binding the cell adhesion peptide. Both molecules remained on the surface and active using all three reaction sequences and after autoclave sterilization based on osteoblast attachment, bacterial turbidity and bacterial zone inhibition test results. However, the second strategy was superior at enhancing osteoblast attachment and significantly decreasing bacterial growth when compared to the other sequences. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioactive hydrogel-nanosilica hybrid materials: a potential injectable scaffold for bone tissue engineering.

PubMed

Lewandowska-Łańcucka, Joanna; Fiejdasz, Sylwia; Rodzik, Łucja; Kozieł, Marcin; Nowakowska, Maria

2015-02-10

Novel bioactive organic-inorganic hybrid materials that can serve as injectable hydrogel systems for bone tissue regeneration were obtained. The silica nanoparticles (SiNP) prepared in situ by the Stöber method were dispersed in collagen, collagen-chitosan or chitosan sols, which were then subsequently crosslinked. Laser scanning confocal microscopy studies, in which fluorescent SiNP were applied, and SEM images indicated that the nanosilica particles were distributed in the whole volume of the hydrogel matrix. In vitro studies on fibroblast cell viability indicated that the hybrid materials are biocompatible. The silica nanoparticles dispersed in the biopolymer matrix had a positive effect on cell viability. Studies on the mineralization process under simulated body fluid (SBF) conditions confirmed the bioactivity of prepared materials. SEM images revealed mineral phase formation in the majority of the hybrid materials developed. EDS analysis indicated that these mineral phases are mainly composed of calcium and phosphorus. The XRD studies confirmed that mineral phases formed during SBF incubation of hybrid materials based on collagen are bone-like apatite minerals. The silica nanoparticles added to the hydrogel at the stage of synthesis induced the occurrence of mineralization. This process occurs not only at the surface of the material but in its entire volume, which is important for the preparation of scaffolds for bone tissue engineering. The ability of these materials to undergo in situ gelation under physiological temperature and their bioactivity as well as biocompatibility make them interesting candidates for bioactive injectable systems.

Antifungal and Antiviral Cyclic Peptides from the Deep-Sea-Derived Fungus Simplicillium obclavatum EIODSF 020.

PubMed

Liang, Xiao; Nong, Xu-Hua; Huang, Zhong-Hui; Qi, Shu-Hua

2017-06-28

A new linear peptide simplicilliumtide I (1) and four new cyclic peptides simplicilliumtides J-M (2-5) together with known analogues verlamelins A and B (6 and 7) were isolated from the deep-sea-derived fungal strain Simplicillium obclavatum EIODSF 020. Their structures were elucidated by spectroscopic analysis, and their absolute configurations were further confirmed by chemical structural modification, Marfey's and Mosher's methods. Compounds 2, 6, and 7 showed significant antifungal activity toward Aspergillus versicolor and Curvularia australiensis and also had obvious antiviral activity toward HSV-1 with IC 50 values of 14.0, 16.7, and 15.6 μM, respectively. The structure-bioactivity relationship of this type of cyclic peptide was also discussed. This is the first time to discuss the effects of the lactone linkage and the substituent group of the fatty acid chain fragment on the bioactivity of this type of cyclic peptides. This is also the first time to report the antiviral activity of these cyclic peptides.

Antioxidant Peptides from Terrestrial and Aquatic Plants Against Cancer.

PubMed

Marquez-Rios, Enrique; Del-Toro-Sanchez, Carmen Lizette

2018-02-13

Cancer is the leading cause of morbidity and mortality worldwide. Therefore, the search for new and less aggressive treatments is currently the focus of the anticancer research. An attractive alternative for this purpose is the use of bioactive peptides from plants. Plants live everywhere on Earth, both on land and in water, and they are a major source of diverse molecules with pharmacological potential as antioxidant peptides. Hence, this review focuses on the importance of the antioxidant activity of terrestrial and aquatic plant peptides against cancer throughout several mechanisms. The influence of the antioxidant activity of peptides by different factors such as molecular weight and amino acid composition as a crucial factor for anticancer activity is also revised. Furthermore, the relation of antioxidant activity with anticancer property as well as safety and legal aspects of protein hydrolysates and bioactive peptides for their use in cancer treatments is discussed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Preparation of porous collagen/hyaluronic acid hybrid scaffolds for biomimetic functionalization through biochemical binding affinity.

PubMed

Lee, Su Jin; Kim, So Yeon; Lee, Young Moo

2007-08-01

This study demonstrated the feasibility of introducing an avidin-biotin system to three-dimensional and highly porous scaffolds for the purpose of designing scaffolds that have binding affinity with bioactive molecules for various biomimetic modifications. Porous hybrid scaffolds composed of collagen and hyaluronic acid (HA) were prepared by a novel overrun process. The overrun-processed scaffolds showed a uniform dual-pore structure because of the injection of gas bubbles and ice recrystallization during the fabrication process and had a higher porosity than scaffolds prepared by a conventional freeze-drying method. The mechanical strength and biodegradation kinetics were controlled by the method of preparation and the composition of collagen/HA. Collagen/HA scaffolds did not show any significant adverse effects on cell viability even after 10 days of incubation. The fibroblasts cultured in the overrun-processed scaffolds were widely distributed and had proliferated on the surfaces of the macropores in the scaffolds, whereas the cells that were seeded in the freeze-dried scaffolds had attached mainly on the dense surface of the scaffolds. As the collagen content in the scaffolds increased, the cellular ingrowth into the inner pores of the scaffolds decreased because of the high affinity between the collagen and the cells. Measurements obtained via confocal microscopy revealed that the porous collagen/HA scaffolds could be functionalized with the biotin by incorporating avidin. Therefore, the present biotinylation approach may allow the incorporation of various bioactive molecules (DNA, growth factors, drug, peptide, etc) into the three-dimensional porous scaffolds.

The presence of food-derived collagen peptides in human body-structure and biological activity.

PubMed

Sato, Kenji

2017-12-13

It has been demonstrated that the ingestion of some protein hydrolysates exerts health-promoting effects. For understanding the underlying mechanisms responsible for these effects, the identification of bioactive peptides in the target organ is crucial. For this purpose, in vitro activity-guided fractionation for peptides in the protein hydrolysate has been performed. However, the peptides in the hydrolysate may be further degraded during digestion. The concentration of the active peptides, which were identified by in vitro activity-guided fractionation, in human blood is frequently very low (nanomolar levels). In contrast, micromolar levels of food-derived collagen peptides are present in human blood. Pro-Hyp, one of the major food-derived collagen peptides, enhances the growth of fibroblasts and synthesis of hyaluronic acid. These observations partially explain the beneficial effects of collagen hydrolysate ingestion on the enhancement of wound healing and improvement in the skin condition. The recent advancement involving liquid chromatography and mass spectrometry coupled with a pre-column derivatization technique has enabled the identification of food-derived peptides at nanomolar levels in the body post-ingestion of protein hydrolysates. Thus, this technique can be used for the identification of bioactive food-derived peptides in the body.

From Mollusks to Medicine: A Venomics Approach for the Discovery and Characterization of Therapeutics from Terebridae Peptide Toxins.

PubMed

Verdes, Aida; Anand, Prachi; Gorson, Juliette; Jannetti, Stephen; Kelly, Patrick; Leffler, Abba; Simpson, Danny; Ramrattan, Girish; Holford, Mandë

2016-04-19

Animal venoms comprise a diversity of peptide toxins that manipulate molecular targets such as ion channels and receptors, making venom peptides attractive candidates for the development of therapeutics to benefit human health. However, identifying bioactive venom peptides remains a significant challenge. In this review we describe our particular venomics strategy for the discovery, characterization, and optimization of Terebridae venom peptides, teretoxins. Our strategy reflects the scientific path from mollusks to medicine in an integrative sequential approach with the following steps: (1) delimitation of venomous Terebridae lineages through taxonomic and phylogenetic analyses; (2) identification and classification of putative teretoxins through omics methodologies, including genomics, transcriptomics, and proteomics; (3) chemical and recombinant synthesis of promising peptide toxins; (4) structural characterization through experimental and computational methods; (5) determination of teretoxin bioactivity and molecular function through biological assays and computational modeling; (6) optimization of peptide toxin affinity and selectivity to molecular target; and (7) development of strategies for effective delivery of venom peptide therapeutics. While our research focuses on terebrids, the venomics approach outlined here can be applied to the discovery and characterization of peptide toxins from any venomous taxa.

Rational design of bioactive, modularly assembled aminoglycosides targeting the RNA that causes myotonic dystrophy type 1.

PubMed

Childs-Disney, Jessica L; Parkesh, Raman; Nakamori, Masayuki; Thornton, Charles A; Disney, Matthew D

2012-12-21

Myotonic dystrophy type 1 (DM1) is caused when an expanded r(CUG) repeat (r(CUG)(exp)) binds the RNA splicing regulator muscleblind-like 1 protein (MBNL1) as well as other proteins. Previously, we reported that modularly assembled small molecules displaying a 6'-N-5-hexynoate kanamycin A RNA-binding module (K) on a peptoid backbone potently inhibit the binding of MBNL1 to r(CUG)(exp). However, these parent compounds are not appreciably active in cell-based models of DM1. The lack of potency was traced to suboptimal cellular permeability and localization. To improve these properties, second-generation compounds that are conjugated to a d-Arg(9) molecular transporter were synthesized. These modified compounds enter cells in higher concentrations than the parent compounds and are efficacious in cell-based DM1 model systems at low micromolar concentrations. In particular, they improve three defects that are the hallmarks of DM1: a translational defect due to nuclear retention of transcripts containing r(CUG)(exp); pre-mRNA splicing defects due to inactivation of MBNL1; and the formation of nuclear foci. The best compound in cell-based studies was tested in a mouse model of DM1. Modest improvement of pre-mRNA splicing defects was observed. These studies suggest that a modular assembly approach can afford bioactive compounds that target RNA.

Rational Design of Bioactive, Modularly Assembled Aminoglycosides Targeting the RNA that Causes Myotonic Dystrophy Type 1

PubMed Central

Childs-Disney, Jessica L.; Parkesh, Raman; Nakamori, Masayuki; Thornton, Charles A.; Disney, Matthew D.

2012-01-01

Myotonic dystrophy type 1 (DM1) is caused when an expanded r(CUG) repeat (r(CUG)exp) binds the RNA splicing regulator muscleblind-like 1 protein (MBNL1) as well as other proteins. Previously, we reported that modularly assembled small molecules displaying a 6′-N-5-hexynoate kanamycin A RNA-binding module (K) on a peptoid backbone potently inhibit the binding of MBNL1 to r(CUG)exp. However, these parent compounds are not appreciably active in cell-based models of DM1. The lack of potency was traced to suboptimal cellular permeability and localization. To improve these properties, second-generation compounds that are conjugated to a D-Arg9 molecular transporter were synthesized. These modified compounds enter cells in higher concentrations than the parent compounds and are efficacious in cell-based DM1 model systems at low micromolar concentrations. In particular, they improve three defects that are the hallmarks of DM1: a translational defect due to nuclear retention of transcripts containing r(CUG)exp; pre-mRNA splicing defects due to inactivation of MBNL1; and the formation of nuclear foci. The best compound in cell-based studies was tested in a mouse model of DM1. Modest improvement of pre-mRNA splicing defects was observed. These studies suggest that a modular assembly approach can afford bioactive compounds that target RNA. PMID:23130637

Peptoid nanosheets as soluble, two-dimensional templates for calcium carbonate mineralization.

PubMed

Jun, Joo Myung V; Altoe, M Virginia P; Aloni, Shaul; Zuckermann, Ronald N

2015-06-25

Nacre-mimetic materials are of great interest, but difficult to synthesize, because they require the ordering of organic and inorganic materials on several length scales. Here we introduce peptoid nanosheets as a versatile two-dimensional platform to develop nacre mimetic materials. Free-floating zwitterionic nanosheets were mineralized with thin films of amorphous calcium carbonate (of 2-20 nm thickness) on their surface to produce planar nacre synthons. These can serve as tunable building blocks to produce layered brick and mortar nanoarchitectures.

N-Sulfanylethylaminooxybutyramide (SEAoxy): A Crypto-Thioester Compatible with Fmoc Solid-Phase Peptide Synthesis.

PubMed

Tsuda, Shugo; Mochizuki, Masayoshi; Sakamoto, Ken; Denda, Masaya; Nishio, Hideki; Otaka, Akira; Yoshiya, Taku

2016-11-18

An N-sulfanylethylaminooxybutyramide (SEAoxy) has been developed as a novel thioester equivalent for native chemical ligation. SEAoxy peptide was straightforwardly synthesized by conventional Fmoc solid-phase peptide synthesis without a problem. Moreover, SEAoxy peptide could be directly applied to native chemical ligation owing to the intramolecular N-to-S acyl shift that releases the peptide-thioester in situ. This methodology was successfully applied to the synthesis of two bioactive peptides.

Nanocarrier possibilities for functional targeting of bioactive peptides and proteins: state-of-the-art.

PubMed

Moutinho, Carla G; Matos, Carla M; Teixeira, José A; Balcão, Victor M

2012-02-01

This review attempts to provide an updated compilation of studies reported in the literature pertaining to production of nanocarriers encasing peptides and/or proteins, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to bioactive proteins and peptides, with a special focus on those from dairy sources (including physicochemical characteristics and properties, and biopharmaceutical application possibilities of e.g. lactoferrin and glycomacropeptide), as well as to nanocarrier functional targeting. Features associated with micro- and (multiple) nanoemulsions, micellar systems, liposomes and solid lipid nanoparticles, together with biopharmaceutical considerations, are presented in the text in a systematic fashion.

In Silico Screening of the Human Gut Metaproteome Identifies Th17-Promoting Peptides Encrypted in Proteins of Commensal Bacteria

PubMed Central

Hidalgo-Cantabrana, Claudio; Moro-García, Marco A.; Blanco-Míguez, Aitor; Fdez-Riverola, Florentino; Lourenço, Anália; Alonso-Arias, Rebeca; Sánchez, Borja

2017-01-01

Scientific studies focused on the role of the human microbiome over human health have generated billions of gigabits of genetic information during the last decade. Nowadays integration of all this information in public databases and development of pipelines allowing us to biotechnologically exploit this information are urgently needed. Prediction of the potential bioactivity of the products encoded by the human gut microbiome, or metaproteome, is the first step for identifying proteins responsible for the molecular interaction between microorganisms and the immune system. We have recently published the Mechanism of Action of the Human Microbiome (MAHMI) database (http://www.mahmi.org), conceived as a resource compiling peptide sequences with a potential immunomodulatory activity. Fifteen out of the 300 hundred million peptides contained in the MAHMI database were synthesized. These peptides were identified as being encrypted in proteins produced by gut microbiota members, they do not contain cleavage points for the major intestinal endoproteases and displayed high probability to have immunomodulatory bioactivity. The bacterial peptides FR-16 and LR-17 encrypted in proteins from Bifidobacterium longum DJ010A and Bifidobacterium fragilis YCH46 respectively, showed the higher immune modulation capability over human peripheral blood mononuclear cells. Both peptides modulated the immune response toward increases in the Th17 and decreases in the Th1 cell response, together with an induction of IL-22 production. These results strongly suggest the combined use of bioinformatics and in vitro tools as a first stage in the screening of bioactive peptides encrypted in the human gut metaproteome. PMID:28943872

Hard-to-cook bean (Phaseolus vulgaris L.) proteins hydrolyzed by alcalase and bromelain produced bioactive peptide fractions that inhibit targets of type-2 diabetes and oxidative stress.

PubMed

Oseguera-Toledo, Miguel E; Gonzalez de Mejia, Elvira; Amaya-Llano, Silvia L

2015-10-01

The objective was to evaluate the effect of bioactive peptide fractions from de-hulled hard-to-cook (HTC) bean on enzyme targets of type-2 diabetes and oxidative stress. Protein isolates from Pinto Durango and Negro 8025 beans were hydrolyzed (120min) with either alcalase® or bromelain and separated into five peptide fractions (<1, 1-3.5, 3.5-5, 5-10, and >10kDa) using an ultrafiltration membrane system. The <1kDa pinto Durango-bromelain fraction showed the best inhibition of α-amylase (49.9±1.4%), and the <1kDa pinto Durango-alcalase fraction inhibited both, α-glucosidase (76.4±0.5%), and dipeptidyl peptidase-IV (DPP-IV, 55.3±1.6%). Peptides LLSL, QQEG and NEGEAH were present in the most potent fractions. Hydrolysates and peptide fractions showed antioxidant capacity (ORAC: 159.6±2.9 to 932.6±1.1mmolTE/g) and nitric oxide inhibition (57.5±0.9 to 68.3±4.2%). Hydrolysates and fractions <1 and 1-3kDa were able to increase glucose-stimulated insulin secretion from iNS-1E cells up to 57% compared to glucose control. Hydrolysates from HTC beans inhibited enzymes related to diabetes management, being the smallest peptides (<1kDa) the most potent. HTC bean could be a source of protein to produce bioactive peptides with potential antidiabetic properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Anchoring TGF-β1 on biomaterial surface via affinitive interactions: Effects on spatial structures and bioactivity.

PubMed

Xiao, Meng; Xiao, Jiangwei; Wu, Gang; Ke, Yu; Fang, Liming; Deng, Chunlin; Liao, Hua

2018-06-01

Protein adsorption on biomaterial surfaces is clinically applied to increase therapeutic effects; however, this adsorption is possibly accompanied by conformational changes and results in loss of protein bioactivity or adverse reactions. In this research, a transforming growth factor β1 (TGF-β1) affinitive peptide HSNGLPL was grafted onto biopolymer surface to stabilize TGF-β1 spatial conformation after adhesion. The peptide with azide end group was combined with the propynyl pendant group on polyurethane via copper-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction. The final polymer was characterized by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, which indicated that the affinitive peptide was introduced to the polymer. Quartz crystal microbalance with dissipation (QCM-D) was performed to monitor TGF-β1 adsorption and desorption on the surfaces coated with polyurethane with and without peptide combination. Results showed that TGF-β1 adhered on polyurethane surface and formed a compact and rigid layer. This layer showed spatial structural change but presented a loose and diffuse layer on the peptide-grafted polyurethane surface, indicating stable spatial conformation after adherence. Similar regulations were observed on the two surfaces where BSA layer was coated in advance. In vivo animal experiments revealed that immune reactions and tissue regenerations occurred earlier on peptide-modified polyurethane than on polyurethane, which did not undergo peptide grafting. This finding confirmed that affinitive interactions may preserve TGF-β1 bioactivity on polymer surface after adsorption. Copyright © 2018 Elsevier B.V. All rights reserved.

Mitochondria-acting hexokinase II peptides carried by short-length carbon nanotubes with increased cellular uptake, endosomal evasion, and enhanced bioactivity against cancer cells

NASA Astrophysics Data System (ADS)

Yoong, Sia Lee; Lau, Wei Liang; Liu, Ang Yu; Prendergast, D'arcy; Ho, Han Kiat; Yu, Victor Chun Kong; Lee, Chengkuo; Ang, Wee Han; Pastorin, Giorgia

2015-08-01

Type II hexokinase (HKII) has emerged as a viable therapeutic target due to its involvement in metabolic reprogramming and also apoptosis prevention. The peptide derived from the fifteen amino acid sequence in the HKII N-terminal region [HKII(pep)] can compete with endogenous proteins for binding on mitochondria and trigger apoptosis. However, this peptide is not cell-permeable. In this study, multi-walled carbon nanotubes (MWCNTs) were used to effectively deliver HKII(pep) across cellular barriers without compromising their bioactivity. The peptide was conjugated on either oxidized MWCNTs or 2,2'-(ethylenedioxy)bis(ethylamine)-functionalized MWCNTs, yielding MWCNT-HKII(pep) and MWCNT-TEG-HKII(pep), respectively. Both conjugates were shown to be internalized by breast cancer MCF-7 cells using confocal microscopy. Moreover, these nanoconjugates seemed to have escaped from endosomes and be in the vicinity of mitochondria. The WST-1 cytotoxicity assay conducted on MCF-7 and colon carcinoma HCT116 cells revealed that MWCNT-peptide conjugates were significantly more effective in curbing cancer cell growth compared to a commercially available cell permeable HKII fusion peptide. In addition, both nanoconjugates displayed an enhanced ability in eliciting apoptosis and depleting the ATP level in HCT116 cells compared to the mere HKII peptide. Importantly, hexokinase II release from mitochondria was demonstrated in MWCNT-HKII(pep) and MWCNT-TEG-HKII(pep) treated cells, highlighting that the structure and bioactivity of HKII(pep) were not compromised after covalent conjugation to MWCNTs.Type II hexokinase (HKII) has emerged as a viable therapeutic target due to its involvement in metabolic reprogramming and also apoptosis prevention. The peptide derived from the fifteen amino acid sequence in the HKII N-terminal region [HKII(pep)] can compete with endogenous proteins for binding on mitochondria and trigger apoptosis. However, this peptide is not cell-permeable. In this study, multi-walled carbon nanotubes (MWCNTs) were used to effectively deliver HKII(pep) across cellular barriers without compromising their bioactivity. The peptide was conjugated on either oxidized MWCNTs or 2,2'-(ethylenedioxy)bis(ethylamine)-functionalized MWCNTs, yielding MWCNT-HKII(pep) and MWCNT-TEG-HKII(pep), respectively. Both conjugates were shown to be internalized by breast cancer MCF-7 cells using confocal microscopy. Moreover, these nanoconjugates seemed to have escaped from endosomes and be in the vicinity of mitochondria. The WST-1 cytotoxicity assay conducted on MCF-7 and colon carcinoma HCT116 cells revealed that MWCNT-peptide conjugates were significantly more effective in curbing cancer cell growth compared to a commercially available cell permeable HKII fusion peptide. In addition, both nanoconjugates displayed an enhanced ability in eliciting apoptosis and depleting the ATP level in HCT116 cells compared to the mere HKII peptide. Importantly, hexokinase II release from mitochondria was demonstrated in MWCNT-HKII(pep) and MWCNT-TEG-HKII(pep) treated cells, highlighting that the structure and bioactivity of HKII(pep) were not compromised after covalent conjugation to MWCNTs. Electronic supplementary information (ESI) available: Additional TEM images, UV-Vis scanning characterisation, WST-1 assay results, and immunoblotting of HKII in the total cell lysate. See DOI: 10.1039/c5nr00980d

Bioactive peptides released during of digestion of processed milk

USDA-ARS?s Scientific Manuscript database

Most of the proteins contained in milk consist of alpha-s1-, alpha-s2-, beta- and kappa-casein, and some of the peptides contained in these caseins may impart health benefits. To determine if processing affected release of peptides, samples of raw (R), homogenized (H), homogenized and pasteurized (...

Induction of a Humoral Immune Response following an Escherichia coli O157:H7 Infection with an Immunomodulatory Peptidic Fraction Derived from Lactobacillus helveticus-Fermented Milk

PubMed Central

LeBlanc, Jason; Fliss, Ismail; Matar, Chantal

2004-01-01

Numerous beneficial effects have been attributed to probiotic lactic acid bacteria (LAB), such as the stimulation of the immune system, the prevention of enteric infections by enteropathogens, and the regression of immunodependent tumors. It has been shown that biologically active metabolites released during fermentation, in particular biopeptides, could act as immunomodulatory agents. However, no studies have been conducted to evaluate the implication of these bioactive peptides in the induction of a protective immune response against enteric infections. The present study aimed to evaluate the possible immunomodulatory and anti-infectious effects of a peptidic fraction released in milk fermented by Lactobacillus helveticus. The immune response in the mucosa-associated lymphoid tissue was monitored following an administration of the potentially bioactive peptidic fraction. The total immunoglobulin A (IgA) immune response was evaluated after an Escherichia coli O157:H7 infection in a BALB/c murine model. Immunohistochemical and enzyme-linked immunosorbent assays revealed an increase in the number of IgA-secreting B lymphocytes in the intestinal lamina propria and an enhanced total secretory and systemic IgA response. Cytokine profiling also revealed stimulation of a Th2 response in mice fed the peptidic fraction, whereas infected controls demonstrated a proinflammatory Th1 response. These results indicate that bioactive peptides released during fermentation by LAB could contribute to the known immunomodulatory effects of probiotic bacteria. PMID:15539524

Two Novel Bioactive Peptides from Antarctic Krill with Dual Angiotensin Converting Enzyme and Dipeptidyl Peptidase IV Inhibitory Activities.

PubMed

Ji, Wei; Zhang, Chaohua; Ji, Hongwu

2017-07-01

Inhibition of dipeptidyl peptidase IV (DPP-IV) and angiotensin converting enzyme (ACE) are considered useful in managing 2 often associated conditions: diabetes and hypertension. In this study, corolase PP was used to hydrolyze Antarctic krill protein. The hydrolysate (AKH) was isolated by ultrafiltration and purified by size-exclusion chromatography, ion exchange chromatography and reversed-phase high-performance liquid chromatography (RP-HPLC) sequentially. The in vitro inhibitory activities of all AKHs and several fractions obtained against ACE and DPP-IV were assessed. Two peptides, purified with dual-strength inhibitory activity against ACE and DPP-IV, were identified by TOF-MS/MS. Results indicated that not all fractions exhibited dual inhibitory activities of ACE and DPP-IV. The purified peptide Lys-Val-Glu-Pro-Leu-Pro had half-maximal inhibitory concentrations (IC 50 ) of 0.93±0.05 and 0.73±0.04 mg/mL against ACE and DPP-IV, respectively. The other peptide Pro-Ala-Leu had IC 50 values of 0.64±0.05 and 0.88±0.03 mg/mL against ACE and DPP-IV, respectively. This study firstly reported the sequences of dual bioactive peptides from Antarctic krill proteins, further provided new insights into the bioactive peptides responsible for the ACE and DPP-IV inhibitory activities from the Antarctic krill protein hydrolysate to manage hypertension and diabetes. © 2017 Institute of Food Technologists®.

Roles of proteolysis in regulation of GPCR function

PubMed Central

Cottrell, GS

2013-01-01

The enzymatic activity of peptidases must be tightly regulated to prevent uncontrolled hydrolysis of peptide bonds, which could have devastating effects on biological systems. Peptidases are often generated as inactive propeptidases, secreted with endogenous inhibitors, or they are compartmentalized. Propeptidases become active after proteolytic removal of N-terminal activation peptides by other peptidases. Some peptidases only become active towards substrates only at certain pHs, thus confining activity to specific compartments or conditions. This review discusses the different roles proteolysis plays in regulating GPCRs. At the cell-surface, certain GPCRs are regulated by the hydrolytic inactivation of bioactive peptides by membrane-anchored peptidases, which prevent signalling. Conversely, cell-surface peptidases can also generate bioactive peptides, which directly activate GPCRs. Alternatively, cell-surface peptidases activated by GPCRs, can generate bioactive peptides to cause transactivation of receptor tyrosine kinases, thereby promoting signalling. Certain peptidases can signal directly to cells, by cleaving GPCR to initiate intracellular signalling cascades. Intracellular peptidases also regulate GPCRs; lysosomal peptidases destroy GPCRs in lysosomes to permanently terminate signalling and mediate down-regulation; endosomal peptidases cleave internalized peptide agonists to regulate GPCR recycling, resensitization and signalling; and soluble intracellular peptidases also participate in GPCR function by regulating the ubiquitination state of GPCRs, thereby altering GPCR signalling and fate. Although the use of peptidase inhibitors has already brought success in the treatment of diseases such as hypertension, the discovery of new regulatory mechanisms involving proteolysis that control GPCRs may provide additional targets to modulate dysregulated GPCR signalling in disease. PMID:23043558

The Influence of Peptide Modifications of Bioactive Glass on Human Mesenchymal Stem Cell Growth and Function

NASA Astrophysics Data System (ADS)

Ammar, Mohamed

2011-12-01

Bioactive glass is known for its potential as a bone scaffold due to its ability to stimulate osteogenesis and induce bone formation. Broadening this potential to include the differentiation of human mesenchymal stem cells (hMSCs) to bone cells will enhance the healing process in bone defects. The surface of bioactive glass made by the sol-gel technique with the composition of 70% SiO2-30% CaO (mol %) was grafted with 3 peptides sequences in different combinations from proteins (fibronectin BMP-2 and BMP-9) that are known to promote the adhesion, differentiation and osteogenesis process. The experiment was done in two forms, a 2D non-porous thin film and a 3D nano-macroporous structure. hMSCs were grown on the materials for a total of five weeks. The 2D materials were tested for the expression of 3 osteogenic markers (osteopontin, osteocalcin and osteonectin) through immunocytochemistry. The 3D forms were monitored for cell's adhesion, morphology, spreading and proliferation by scanning electron microscopy, in addition to proliferation assay and alkaline phosphatase activity measurement. Results showed that hMSCs poorly adhered to the 2D thin films, but the few cells survived showed enhanced expression of the osteogenic markers. On the 3D form, cells showed enhanced proliferation at week one and more survival of the cells on the materials grafted with the adhesion peptide for the successive weeks in comparison to the positive control samples. Enhanced alkaline phosphatase activity was also detected compared to the negative control samples but were still below the positive control samples. In conclusion, the peptide grafting could increase the effect of bioactive glass but more peptide combinations should be examined to improve the effects on the differentiation and osteogenic activity of the hMSCs.

Glycosaminoglycan-Mimetic Signals Direct the Osteo/Chondrogenic Differentiation of Mesenchymal Stem Cells in a Three-Dimensional Peptide Nanofiber Extracellular Matrix Mimetic Environment.

PubMed

Arslan, Elif; Guler, Mustafa O; Tekinay, Ayse B

2016-04-11

Recent efforts in bioactive scaffold development focus strongly on the elucidation of complex cellular responses through the use of synthetic systems. Designing synthetic extracellular matrix (ECM) materials must be based on understanding of cellular behaviors upon interaction with natural and artificial scaffolds. Hence, due to their ability to mimic both the biochemical and mechanical properties of the native tissue environment, supramolecular assemblies of bioactive peptide nanostructures are especially promising for development of bioactive ECM-mimetic scaffolds. In this study, we used glycosaminoglycan (GAG) mimetic peptide nanofiber gel as a three-dimensional (3D) platform to investigate how cell lineage commitment is altered by external factors. We observed that amount of fetal bovine serum (FBS) presented in the cell media had synergistic effects on the ability of GAG-mimetic nanofiber gel to mediate the differentiation of mesenchymal stem cells into osteogenic and chondrogenic lineages. In particular, lower FBS concentration in the culture medium was observed to enhance osteogenic differentiation while higher amount FBS promotes chondrogenic differentiation in tandem with the effects of the GAG-mimetic 3D peptide nanofiber network, even in the absence of externally administered growth factors. We therefore demonstrate that mesenchymal stem cell differentiation can be specifically controlled by the combined influence of growth medium components and a 3D peptide nanofiber environment.

Effect of enzymatic hydrolysis on bioactive properties and allergenicity of cricket (Gryllodes sigillatus) protein.

PubMed

Hall, Felicia; Johnson, Philip E; Liceaga, Andrea

2018-10-01

Food-derived bioactive peptides have gained attention for their role in preventing chronic diseases. Edible insects are viable sources of bioactive peptides owing to their high protein content and sustainable production. In this study, whole crickets (Gryllodes sigillatus) were alcalase-hydrolyzed to a degree of hydrolysis (DH) ranging from 15 to 85%. Antioxidant activity, angiotensin converting enzyme (ACE), and dipeptidyl peptidase-4 (DPP-IV)- inhibition of the cricket protein hydrolysates (CPH) were evaluated before and after simulated gastrointestinal digestion (SGD). Antioxidant activity was similar among CPH, whereas ACE and DPP-IV inhibition was greater (p < 0.05) in CPH with 60-85% DH. Bioactivity improved after SGD. CPH allergenicity was evaluated using human shrimp-allergic sera. All sera positively reacted to tropomyosin in the unhydrolyzed cricket and CPH with 15-50% DH, whereas 60-85% DH showed no reactivity. In conclusion, CPH (60-85% DH) had the greatest bioactive potential and lowest reactivity to tropomyosin, compared with other CPH and the unhydrolyzed control. Copyright © 2018 Elsevier Ltd. All rights reserved.

Synthesis and characterization of chitosan-polyvinyl alcohol-bioactive glass hybrid membranes.

PubMed

Dias, Luisa L S; Mansur, Herman S; Donnici, Claudio Luis; Pereira, Marivalda M

2011-01-01

The tissue engineering strategy is a new approach for the regeneration of cementum, which is essential for the regeneration of the periodontal tissue. This strategy involves the cell cultures present in this tissue, called cementoblasts, and located on an appropriate substrate for posterior implantation in the regeneration site. Prior studies from our research group have shown that the proliferation and viability of cementoblasts increase in the presence of the ionic dissolution products of bioactive glass particles. Therefore, one possible approach to obtaining adequate substrates for cementoblast cultures is the development of composite membranes containing bioactive glass. In the present study, composite films of chitosan-polyvinyl alcohol-bioactive glass containing different glass contents were developed. Glutaraldehyde was also added to allow for the formation of cross-links and changes in the degradation rate. The glass phase was introduced in the material by a sol-gel route, leading to an organic-inorganic hybrid. The films were characterized by Fourier-transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Bioactivity tests were also conducted by immersion of the films in simulated body fluid (SBF). Films containing up to 30% glass phase could be obtained. The formation of calcium phosphate was observed after the immersion of the films. A calcium phosphate layer formed more quickly on materials containing higher bioactive glass contents. In the hybrid containing 23% bioactive glass, a complete layer was formed after 24 h immersion, showing the high bioactivity of this material. However, despite the higher in vitro bioactivity, the film with 23% glass showed lower mechanical properties compared with films containing up to 17% glass.

Design of Embedded-Hybrid Antimicrobial Peptides with Enhanced Cell Selectivity and Anti-Biofilm Activity

PubMed Central

Xu, Wei; Zhu, Xin; Tan, Tingting; Li, Weizhong; Shan, Anshan

2014-01-01

Antimicrobial peptides have attracted considerable attention because of their broad-spectrum antimicrobial activity and their low prognostic to induce antibiotic resistance which is the most common source of failure in bacterial infection treatment along with biofilms. The method to design hybrid peptide integrating different functional domains of peptides has many advantages. In this study, we designed an embedded-hybrid peptide R-FV-I16 by replacing a functional defective sequence RR7 with the anti-biofilm sequence FV7 embedded in the middle position of peptide RI16. The results demonstrated that the synthetic hybrid the peptide R-FV-I16 had potent antimicrobial activity over a wide range of Gram-negative and Gram-positive bacteria, as well as anti-biofilm activity. More importantly, R-FV-I16 showed lower hemolytic activity and cytotoxicity. Fluorescent assays demonstrated that R-FV-I16 depolarized the outer and the inner bacterial membranes, while scanning electron microscopy and transmission electron microscopy further indicated that this peptide killed bacterial cells by disrupting the cell membrane, thereby damaging membrane integrity. Results from SEM also provided evidence that R-FV-I16 inherited anti-biofilm activity from the functional peptide sequence FV7. Embedded-hybrid peptides could provide a new pattern for combining different functional domains and showing an effective avenue to screen for novel antimicrobial agents. PMID:24945359

Peptide regulators of peripheral taste function.

PubMed

Dotson, Cedrick D; Geraedts, Maartje C P; Munger, Steven D

2013-03-01

The peripheral sensory organ of the gustatory system, the taste bud, contains a heterogeneous collection of sensory cells. These taste cells can differ in the stimuli to which they respond and the receptors and other signaling molecules they employ to transduce and encode those stimuli. This molecular diversity extends to the expression of a varied repertoire of bioactive peptides that appear to play important functional roles in signaling taste information between the taste cells and afferent sensory nerves and/or in processing sensory signals within the taste bud itself. Here, we review studies that examine the expression of bioactive peptides in the taste bud and the impact of those peptides on taste functions. Many of these peptides produced in taste buds are known to affect appetite, satiety or metabolism through their actions in the brain, pancreas and other organs, suggesting a functional link between the gustatory system and the neural and endocrine systems that regulate feeding and nutrient utilization. Copyright © 2013 Elsevier Ltd. All rights reserved.

Towards 4th generation biomaterials: a covalent hybrid polymer-ormoglass architecture

NASA Astrophysics Data System (ADS)

Sachot, N.; Mateos-Timoneda, M. A.; Planell, J. A.; Velders, A. H.; Lewandowska, M.; Engel, E.; Castaño, O.

2015-09-01

Hybrid materials are being extensively investigated with the aim of mimicking the ECM microenvironment to develop effective solutions for bone tissue engineering. However, the common drawbacks of a hybrid material are the lack of interactions between the scaffold's constituents and the masking of its bioactive phase. Conventional hybrids often degrade in a non-homogeneous manner and the biological response is far from optimal. We have developed a novel material with strong interactions between constituents. The bioactive phase is directly exposed on its surface mimicking the structure of the ECM of bone. Here, polylactic acid electrospun fibers have been successfully and reproducibly coated with a bioactive organically modified glass (ormoglass, Si-Ca-P2 system) covalently. In comparison with the pure polymeric mats, the fibers obtained showed improved hydrophilicity and mechanical properties, bioactive ion release, exhibited a nanoroughness and enabled good cell adhesion and spreading after just one day of culture (rMSCs and rEPCs). The fibers were coated with different ormoglass compositions to tailor their surface properties (roughness, stiffness, and morphology) by modifying the experimental parameters. Knowing that cells modulate their behavior according to the exposed physical and chemical signals, the development of this instructive material is a valuable advance in the design of functional regenerative biomaterials.Hybrid materials are being extensively investigated with the aim of mimicking the ECM microenvironment to develop effective solutions for bone tissue engineering. However, the common drawbacks of a hybrid material are the lack of interactions between the scaffold's constituents and the masking of its bioactive phase. Conventional hybrids often degrade in a non-homogeneous manner and the biological response is far from optimal. We have developed a novel material with strong interactions between constituents. The bioactive phase is directly exposed on its surface mimicking the structure of the ECM of bone. Here, polylactic acid electrospun fibers have been successfully and reproducibly coated with a bioactive organically modified glass (ormoglass, Si-Ca-P2 system) covalently. In comparison with the pure polymeric mats, the fibers obtained showed improved hydrophilicity and mechanical properties, bioactive ion release, exhibited a nanoroughness and enabled good cell adhesion and spreading after just one day of culture (rMSCs and rEPCs). The fibers were coated with different ormoglass compositions to tailor their surface properties (roughness, stiffness, and morphology) by modifying the experimental parameters. Knowing that cells modulate their behavior according to the exposed physical and chemical signals, the development of this instructive material is a valuable advance in the design of functional regenerative biomaterials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04275e

Identification of novel Amurin-2 variants from the skin secretion of Rana amurensis, and the design of cationicity-enhanced analogues.

PubMed

Zhang, Luyao; Chen, Xiaoling; Zhang, Ying; Ma, Chengbang; Xi, Xinping; Wang, Lei; Zhou, Mei; Burrows, James F; Chen, Tianbao

2018-03-18

Rana amurensis is important in Chinese medicine as its skin secretions contain abundant bioactive peptides. Here, we have identified the antimicrobial peptide Amurin-2 and three highly-conserved variants, Amurin-2a, Amurin-2b and Amurin-2c through a combination of molecular cloning and MS/MS fragmentation sequencing. Synthetic replicates of these peptides demonstrate potent antimicrobial activity against S. aureus, whilst some have activity against C.albicans and even resistant bacterial MRSA. Furthermore, two Lys-analogues (K 4 -Amurin-2 and K 11 -Amurin-2) were designed to improve the bioactive function and the antimicrobial activity of K 4 -Amurin-2 against E.coli was enhanced distinctly. In addition, the two modified peptides also showed more potent activity against S. aureus, C. albicans and MRSA strains. Meanwhile, these peptides showed inhibitory effect on the cell viability of several cancer cells. As a result, these structural and functional studies of Amurin-2 variants and analogues could provide insights for future antimicrobial peptide design. Copyright © 2018. Published by Elsevier Inc.

Inhibition on JAK-STAT3 Signaling Transduction Cascade Is Taken by Bioactive Peptide Alpha-S2 Casein Protein from Goat Ethawah Breed Milk

PubMed Central

Rohmah, Rista Nikmatu; Hardiyanti, Ferlany; Fatchiyah, Fatchiyah

2015-01-01

Background: RA is a systemic inflammatory disease that causes developing comorbidity conditions. This condition can cause by overproduction of pro-inflammatory cytokine. In a previous study, we have found bioactive peptide CSN1S2 from Ethawah goat milk for anti-inflammatory for repair the ileum destruction. However, the signaling transduction cascade of bioactive peptides inhibits inflammation still not clear yet. Therefore, we analyzed the signaling transduction cascade via JAK-STAT3 pathway by in vivo and in silico. Methods: The ileum was isolated DNA and amplification with specific primer. The sequence was analyzed using the Sanger sequencing method. Modeling 3D-structure was predicted by SWISS-MODEL and virtual interaction was analyzed by docking system using Pymol and Discovery Studio 4.0 software. Results: This study showed that STAT3 has target gene 480bp. The normal group and normal treating- CSN1S2 of goat milk have similarity from gene bank. Whereas, RA group had transversion mutation that the purine change into pyrimidine even cause frameshift mutation. Interestingly, after treating with the CSN1S2 protein of goat milk shows reverse to the normal acid sequence group. Based on in silico study, from eight peptides, only three peptides of CSN1S2 protein, which carried by PePT1 to enter the small intestine. The fragments are PepT1-41-NMAIHPR-47; PepT1-182-KISQYYQK-189 and PepT1-214-TNAIPYVR-221. We have found just one bioactive peptide of f182-KISQYYQK-189 is able bind to STAT3. The energy binding of f182-KISQYYQK-189 and RA-STAT3 amino acid, it was Σ = -402.43 kJ/mol and the energy binding of f182-KISQYYQK-189 and RAS-STAT3 amino acid is decreasing into Σ = -407.09 kJ/mol. Conclusion: This study suggested that the fragment 182-KISQYYQK-189 peptides from Ethawah goat milk may act as an anti-inflammatory agent via JAK-STAT3 signal transduction cascade at the cellular level. PMID:26483598

Identification of multifunctional peptides from human milk.

PubMed

Mandal, Santi M; Bharti, Rashmi; Porto, William F; Gauri, Samiran S; Mandal, Mahitosh; Franco, Octavio L; Ghosh, Ananta K

2014-06-01

Pharmaceutical industries have renewed interest in screening multifunctional bioactive peptides as a marketable product in health care applications. In this context, several animal and plant peptides with potential bioactivity have been reported. Milk proteins and peptides have received much attention as a source of health-enhancing components to be incorporated into nutraceuticals and functional foods. By using this source, 24 peptides have been fractionated and purified from human milk using RP-HPLC. Multifunctional roles including antimicrobial, antioxidant and growth stimulating activity have been evaluated in all 24 fractions. Nevertheless, only four fractions show multiple combined activities among them. Using a proteomic approach, two of these four peptides have been identified as lactoferrin derived peptide and kappa casein short chain peptide. Lactoferrin derived peptide (f8) is arginine-rich and kappa casein derived (f12) peptide is proline-rich. Both peptides (f8 and f12) showed antimicrobial activities against both Gram-positive and Gram-negative bacteria. Fraction 8 (f8) exhibits growth stimulating activity in 3T3 cell line and f12 shows higher free radical scavenging activity in comparison to other fractions. Finally, both peptides were in silico evaluated and some insights into their mechanism of action were provided. Thus, results indicate that these identified peptides have multiple biological activities which are valuable for the quick development of the neonate and may be considered as potential biotechnological products for nutraceutical industry. Copyright © 2014 Elsevier Inc. All rights reserved.

Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge.

PubMed

Martins, Joana; Vasconcelos, Vitor

2015-11-13

Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential.

Biological effects of a de novo designed myxoma virus peptide analogue: evaluation of cytotoxicity on tumor cells.

PubMed

Istivan, Taghrid S; Pirogova, Elena; Gan, Emily; Almansour, Nahlah M; Coloe, Peter J; Cosic, Irena

2011-01-01

The Resonant Recognition Model (RRM) is a physico-mathematical model that interprets protein sequence linear information using digital signal processing methods. In this study the RRM concept was employed for structure-function analysis of myxoma virus (MV) proteins and the design of a short bioactive therapeutic peptide with MV-like antitumor/cytotoxic activity. The analogue RRM-MV was designed by RRM as a linear 18 aa 2.3 kDa peptide. The biological activity of this computationally designed peptide analogue against cancer and normal cell lines was investigated. The cellular cytotoxicity effects were confirmed by confocal immunofluorescence microscopy, by measuring the levels of cytoplasmic lactate dehydrogenase (LDH) and by Prestoblue cell viability assay for up to 72 hours in peptide treated and non-treated cell cultures. Our results revealed that RRM-MV induced a significant dose and time-dependent cytotoxic effect on murine and human cancer cell lines. Yet, when normal murine cell lines were similarly treated with RRM-MV, no cytotoxic effects were observed. Furthermore, the non-bioactive RRM designed peptide RRM-C produced negligible cytotoxic effects on these cancer and normal cell lines when used at similar concentrations. The presence/absence of phosphorylated Akt activity in B16F0 mouse melanoma cells was assessed to indicate the possible apoptosis signalling pathway that could be affected by the peptide treatment. So far, Akt activity did not seem to be significantly affected by RRM-MV as is the case for the original viral protein. Our findings indicate the successful application of the RRM concept to design a bioactive peptide analogue (RRM-MV) with cytotoxic effects on tumor cells only. This 2.345 kDa peptide analogue to a 49 kDa viral protein may be suitable to be developed as a potential cancer therapeutic. These results also open a new direction to the rational design of therapeutic agents for future cancer treatment.

Biological Effects of a De Novo Designed Myxoma Virus Peptide Analogue: Evaluation of Cytotoxicity on Tumor Cells

PubMed Central

Istivan, Taghrid S.; Pirogova, Elena; Gan, Emily; Almansour, Nahlah M.; Coloe, Peter J.; Cosic, Irena

2011-01-01

Background The Resonant Recognition Model (RRM) is a physico-mathematical model that interprets protein sequence linear information using digital signal processing methods. In this study the RRM concept was employed for structure-function analysis of myxoma virus (MV) proteins and the design of a short bioactive therapeutic peptide with MV-like antitumor/cytotoxic activity. Methodology/Principal Findings The analogue RRM-MV was designed by RRM as a linear 18 aa 2.3 kDa peptide. The biological activity of this computationally designed peptide analogue against cancer and normal cell lines was investigated. The cellular cytotoxicity effects were confirmed by confocal immunofluorescence microscopy, by measuring the levels of cytoplasmic lactate dehydrogenase (LDH) and by Prestoblue cell viability assay for up to 72 hours in peptide treated and non-treated cell cultures. Our results revealed that RRM-MV induced a significant dose and time-dependent cytotoxic effect on murine and human cancer cell lines. Yet, when normal murine cell lines were similarly treated with RRM-MV, no cytotoxic effects were observed. Furthermore, the non-bioactive RRM designed peptide RRM-C produced negligible cytotoxic effects on these cancer and normal cell lines when used at similar concentrations. The presence/absence of phosphorylated Akt activity in B16F0 mouse melanoma cells was assessed to indicate the possible apoptosis signalling pathway that could be affected by the peptide treatment. So far, Akt activity did not seem to be significantly affected by RRM-MV as is the case for the original viral protein. Conclusions/Significance Our findings indicate the successful application of the RRM concept to design a bioactive peptide analogue (RRM-MV) with cytotoxic effects on tumor cells only. This 2.345 kDa peptide analogue to a 49 kDa viral protein may be suitable to be developed as a potential cancer therapeutic. These results also open a new direction to the rational design of therapeutic agents for future cancer treatment. PMID:21949758

Surface coating of siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers: enhanced gene silencing and reduced adverse effects in vitro

NASA Astrophysics Data System (ADS)

Zeng, Xianghui; de Groot, Anne Marit; Sijts, Alice J. A. M.; Broere, Femke; Oude Blenke, Erik; Colombo, Stefano; van Eden, Willem; Franzyk, Henrik; Nielsen, Hanne Mørck; Foged, Camilla

2015-11-01

Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers.Cationic vectors have demonstrated the potential to facilitate intracellular delivery of therapeutic oligonucleotides. However, enhanced transfection efficiency is usually associated with adverse effects, which also proves to be a challenge for vectors based on cationic peptides. In this study a series of proteolytically stable palmitoylated α-peptide/β-peptoid peptidomimetics with a systematically varied number of repeating lysine and homoarginine residues was shown to self-assemble with small interfering RNA (siRNA). The resulting well-defined nanocomplexes were coated with anionic lipids giving rise to net anionic liposomes. These complexes and the corresponding liposomes were optimized towards efficient gene silencing and low adverse effects. The optimal anionic liposomes mediated a high silencing effect, which was comparable to that of the control (cationic Lipofectamine 2000), and did not display any noticeable cytotoxicity and immunogenicity in vitro. In contrast, the corresponding nanocomplexes mediated a reduced silencing effect with a more narrow safety window. The surface coating with anionic lipid bilayers led to partial decomplexation of the siRNA-peptidomimetic nanocomplex core of the liposomes, which facilitated siRNA release. Additionally, the optimal anionic liposomes showed efficient intracellular uptake and endosomal escape. Therefore, these findings suggest that a more efficacious and safe formulation can be achieved by surface coating of the siRNA-peptidomimetic nano-self-assemblies with anionic lipid bilayers. Electronic supplementary information (ESI) available: Non-fusogenic liposomes; cytotoxicity of naked siRNA and the empty vector; immunogenicity; low-magnification images; DOPE/DPPC liposomes. See DOI: 10.1039/c5nr04807a

Comprehensive solid-phase extraction of multitudinous bioactive peptides from equine plasma and urine for doping detection.

PubMed

Guan, Fuyu; Robinson, Mary A

2017-09-08

The ability to analyze biological samples for multitudinous exogenous peptides with a single analytical method is desired for doping control in horse racing. The key to achieving this goal is the capability of extracting all target peptides from the sample matrix. In the present study, theory of mixed-mode solid-phase extraction (SPE) of peptides from plasma is described, and a generic mixed-mode SPE procedure has been developed for recovering multitudinous exogenous peptides with remarkable sequence diversity, from equine plasma and urine in a single procedure. Both the theory and the developed SPE procedure have led to the development of a novel analytical method for comprehensive detection of multitudinous bioactive peptides in equine plasma and urine using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS). Thirty nine bioactive peptides were extracted with strong anion-exchange mixed-mode SPE sorbent, separated on a reversed-phase C 18 column and detected by HRMS and data-dependent tandem mass spectrometry. The limit of detection (LOD) was 10-50 pg mL -1 in plasma for most of the peptides and 100 pg mL -1 for the remaining. For urine, LOD was 20-400 pg mL -1 for most of the peptides and 1-4 ng mL -1 for the others. In vitro degradation of the peptides in equine plasma and urine was examined at ambient temperature; the peptides except those with a D-amino acid at position 2 were unstable not only in plasma but also in urine. The developed method was successful in analysis of plasma and urine samples from horses administered dermorphin. Additionally, dermorphin metabolites were identified in the absence of reference standards. The developed SPE procedure and LC-HRMS method can theoretically detect virtually all peptides present at a sufficient concentration in a sample. New peptides can be readily included in the method to be detected without method re-development. The developed method also generates such data that can be retrospectively analyzed for peptides unknown at the time of sample analysis. It is the first generic analytical method for comprehensive detection of multitudinous exogenous peptides in biological samples, to the authors' knowledge. Copyright © 2017 Elsevier B.V. All rights reserved.

Amino acids and peptides. XXXII: A bifunctional poly(ethylene glycol) hybrid of fibronectin-related peptides.

PubMed

Maeda, M; Izuno, Y; Kawasaki, K; Kaneda, Y; Mu, Y; Tsutsumi, Y; Lem, K W; Mayumi, T

1997-12-18

An amino acid type poly(ethylene glycol) (aaPPEG) was prepared and its application to a drug carrier was examined. The peptides, Arg-Gly-Asp (RGD) and Glu-Ile-Leu-Asp-Val (EILDV) which were reported as active fragments of Fibronectin (a cell adhesion protein), were conjugated with aaPEG (molecular weight, 10,000). The hybrid, RGD-aaPEG-EILDV, was prepared by a combination of the solid-phase method and the solution method. Antiadhesive activity of the peptides was not lost by its hybrid formation with the large aaPEG molecule. A mixture of RGD (0.43 mmol) and EILDV (0.43 mmol) did not demonstrate an antiadhesive effect, but the hybrid containing 0.43 mmol of each peptide did exhibit this effect.

The efficacy of chimeric vaccines constructed with PEP-1 and Ii-Key linking to a hybrid epitope from heterologous viruses.

PubMed

Liu, Xue-lan; Shan, Wen-jie; Xu, Shan-shan; Zhang, Jin-jing; Xu, Fa-zhi; Xia, Sheng-lin; Dai, Yin

2015-09-01

The heterologous epitope-peptide from different viruses may represent an attractive candidate vaccine. In order to evaluate the role of cell-permeable peptide (PEP-1) and Ii-Key moiety from the invariant chain (Ii) of MHC on the heterologous peptide chimeras, we linked the two vehicles to hybrid epitopes on the VP2 protein (aa197-209) of the infectious bursal disease virus and HN protein (aa345-353) of the Newcastle disease virus. The chimeric vaccines were prepared and injected into mice. The immune effects were measured by indirect ELISA. The results showed that the vehicle(s) could significantly boost immune effects against the heterologous epitope peptide. The Ii-Key-only carrier induced more effective immunological responses, compared with the PEP-1 and Ii-Key hybrid vehicle. The carrier-peptide hybrids all showed strong colocalization with major histocompatibility complex (MHC) class II molecules compared with the epitope-peptide (weakly-binding) after co-transfection into 293T cells. Together, our results lay the groundwork for designing new hybrid vaccines based on Ii-Key and/or PEP-1 peptides. Copyright © 2015 The International Alliance for Biological Standardization. Published by Elsevier Ltd. All rights reserved.

Robotic deposition and in vitro characterization of 3D gelatin-bioactive glass hybrid scaffolds for biomedical applications.

PubMed

Gao, Chunxia; Rahaman, Mohamed N; Gao, Qiang; Teramoto, Akira; Abe, Koji

2013-07-01

The development of inorganic-organic hybrid scaffolds with controllable degradation and bioactive properties is receiving considerable interest for bone and tissue regeneration. The objective of this study was to create hybrid scaffolds of gelatin and bioactive glass (BG) with a controlled, three-dimensional (3D) architecture by a combined sol-gel and robotic deposition (robocasting) method and evaluate their mechanical response, bioactivity, and response to cells in vitro. Inks for robotic deposition of the scaffolds were prepared by dissolving gelatin in a sol-gel precursor solution of the bioactive glass (70SiO2 -25CaO-5P2 O5 ; mol%) and aging the solution to form a gel with the requisite viscosity. After drying and crosslinking, the gelatin-BG scaffolds, with a grid-like architecture (filament diameter ∼350 µm; pore width ∼550 µm), showed an elasto-plastic response, with a compressive strength of 5.1 ± 0.6 MPa, in the range of values for human trabecular bone (2-12 MPa). When immersed in phosphate-buffered saline, the crosslinked scaffolds rapidly absorbed water (∼440% of its dry weight after 2 h) and showed an elastic response at deformations up to ∼60%. Immersion of the scaffolds in a simulated body fluid resulted in the formation of a hydroxyapatite-like surface layer within 5 days, indicating their bioactivity in vitro. The scaffolds supported the proliferation, alkaline phosphatase activity, and mineralization of osteogenic MC3T3-E1 cells in vitro, showing their biocompatibility. Altogether, the results indicate that these gelatin-BG hybrid scaffolds with a controlled, 3D architecture of inter-connected pores have potential for use as implants for bone regeneration. Copyright © 2012 Wiley Periodicals, Inc.

At-line nanofractionation with parallel mass spectrometry and bioactivity assessment for the rapid screening of thrombin and factor Xa inhibitors in snake venoms.

PubMed

Mladic, Marija; Zietek, Barbara M; Iyer, Janaki Krishnamoorthy; Hermarij, Philip; Niessen, Wilfried M A; Somsen, Govert W; Kini, R Manjunatha; Kool, Jeroen

2016-02-01

Snake venoms comprise complex mixtures of peptides and proteins causing modulation of diverse physiological functions upon envenomation of the prey organism. The components of snake venoms are studied as research tools and as potential drug candidates. However, the bioactivity determination with subsequent identification and purification of the bioactive compounds is a demanding and often laborious effort involving different analytical and pharmacological techniques. This study describes the development and optimization of an integrated analytical approach for activity profiling and identification of venom constituents targeting the cardiovascular system, thrombin and factor Xa enzymes in particular. The approach developed encompasses reversed-phase liquid chromatography (RPLC) analysis of a crude snake venom with parallel mass spectrometry (MS) and bioactivity analysis. The analytical and pharmacological part in this approach are linked using at-line nanofractionation. This implies that the bioactivity is assessed after high-resolution nanofractionation (6 s/well) onto high-density 384-well microtiter plates and subsequent freeze drying of the plates. The nanofractionation and bioassay conditions were optimized for maintaining LC resolution and achieving good bioassay sensitivity. The developed integrated analytical approach was successfully applied for the fast screening of snake venoms for compounds affecting thrombin and factor Xa activity. Parallel accurate MS measurements provided correlation of observed bioactivity to peptide/protein masses. This resulted in identification of a few interesting peptides with activity towards the drug target factor Xa from a screening campaign involving venoms of 39 snake species. Besides this, many positive protease activity peaks were observed in most venoms analysed. These protease fingerprint chromatograms were found to be similar for evolutionary closely related species and as such might serve as generic snake protease bioactivity fingerprints in biological studies on venoms. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of peptoid-based ligands for the removal of cadmium from biological media

DOE PAGES

Knight, Abigail S.; Zhou, Effie Y.; Francis, Matthew B.

2015-05-14

Cadmium poisoning poses a serious health concern due to cadmium's increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate themore » significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal–ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for the identification of metal–ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning.« less

Development of peptoid-based ligands for the removal of cadmium from biological media

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knight, Abigail S.; Zhou, Effie Y.; Francis, Matthew B.

Cadmium poisoning poses a serious health concern due to cadmium's increasing industrial use, yet there is currently no recommended treatment. The selective coordination of cadmium in a biological environment—i.e. in the presence of serum ions, small molecules, and proteins—is a difficult task. To address this challenge, a combinatorial library of peptoid-based ligands has been evaluated to identify structures that selectively bind to cadmium in human serum with minimal chelation of essential metal ions. Eighteen unique ligands were identified in this screening procedure, and the binding affinity of each was measured using metal titrations monitored by UV-vis spectroscopy. To evaluate themore » significance of each chelating moiety, sequence rearrangements and substitutions were examined. Analysis of a metal–ligand complex by NMR spectroscopy highlighted the importance of particular residues. Depletion experiments were performed in serum mimetics and human serum with exogenously added cadmium. These depletion experiments were used to compare and demonstrate the ability of these peptoids to remove cadmium from blood-like mixtures. In one of these depletion experiments, the peptoid sequence was able to deplete the cadmium to a level comparable to the reported acute toxicity limit. Evaluation of the metal selectivity in buffered solution and in human serum was performed to verify minimal off-target binding. These studies highlight a screening platform for the identification of metal–ligands that are capable of binding in a complex environment. They additionally demonstrate the potential utility of biologically-compatible ligands for the treatment of heavy metal poisoning.« less

Characterisation of minimalist co-assembled fluorenylmethyloxycarbonyl self-assembling peptide systems for presentation of multiple bioactive peptides.

PubMed

Horgan, Conor C; Rodriguez, Alexandra L; Li, Rui; Bruggeman, Kiara F; Stupka, Nicole; Raynes, Jared K; Day, Li; White, John W; Williams, Richard J; Nisbet, David R

2016-07-01

The nanofibrillar structures that underpin self-assembling peptide (SAP) hydrogels offer great potential for the development of finely tuned cellular microenvironments suitable for tissue engineering. However, biofunctionalisation without disruption of the assembly remains a key issue. SAPS present the peptide sequence within their structure, and studies to date have typically focused on including a single biological motif, resulting in chemically and biologically homogenous scaffolds. This limits the utility of these systems, as they cannot effectively mimic the complexity of the multicomponent extracellular matrix (ECM). In this work, we demonstrate the first successful co-assembly of two biologically active SAPs to form a coassembled scaffold of distinct two-component nanofibrils, and demonstrate that this approach is more bioactive than either of the individual systems alone. Here, we use two bioinspired SAPs from two key ECM proteins: Fmoc-FRGDF containing the RGD sequence from fibronectin and Fmoc-DIKVAV containing the IKVAV sequence from laminin. Our results demonstrate that these SAPs are able to co-assemble to form stable hybrid nanofibres containing dual epitopes. Comparison of the co-assembled SAP system to the individual SAP hydrogels and to a mixed system (composed of the two hydrogels mixed together post-assembly) demonstrates its superior stable, transparent, shear-thinning hydrogels at biological pH, ideal characteristics for tissue engineering applications. Importantly, we show that only the coassembled hydrogel is able to induce in vitro multinucleate myotube formation with C2C12 cells. This work illustrates the importance of tissue engineering scaffold functionalisation and the need to develop increasingly advanced multicomponent systems for effective ECM mimicry. Successful control of stem cell fate in tissue engineering applications requires the use of sophisticated scaffolds that deliver biological signals to guide growth and differentiation. The complexity of such processes necessitates the presentation of multiple signals in order to effectively mimic the native extracellular matrix (ECM). Here, we establish the use of two biofunctional, minimalist self-assembling peptides (SAPs) to construct the first co-assembled SAP scaffold. Our work characterises this construct, demonstrating that the physical, chemical, and biological properties of the peptides are maintained during the co-assembly process. Importantly, the coassembled system demonstrates superior biological performance relative to the individual SAPs, highlighting the importance of complex ECM mimicry. This work has important implications for future tissue engineering studies. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Hydrocarbon double-stapling remedies the proteolytic instability of a lengthy peptide therapeutic

PubMed Central

Bird, Gregory H.; Madani, Navid; Perry, Alisa F.; Princiotto, Amy M.; Supko, Jeffrey G.; He, Xiaoying; Gavathiotis, Evripidis; Sodroski, Joseph G.; Walensky, Loren D.

2010-01-01

The pharmacologic utility of lengthy peptides can be hindered by loss of bioactive structure and rapid proteolysis, which limits bioavailability. For example, enfuvirtide (Fuzeon, T20, DP178), a 36-amino acid peptide that inhibits human immunodeficiency virus type 1 (HIV-1) infection by effectively targeting the viral fusion apparatus, has been relegated to a salvage treatment option mostly due to poor in vivo stability and lack of oral bioavailability. To overcome the proteolytic shortcomings of long peptides as therapeutics, we examined the biophysical, biological, and pharmacologic impact of inserting all-hydrocarbon staples into an HIV-1 fusion inhibitor. We find that peptide double-stapling confers striking protease resistance that translates into markedly improved pharmacokinetic properties, including oral absorption. We determined that the hydrocarbon staples create a proteolytic shield by combining reinforcement of overall α-helical structure, which slows the kinetics of proteolysis, with complete blockade of peptide cleavage at constrained sites in the immediate vicinity of the staple. Importantly, double-stapling also optimizes the antiviral activity of HIV-1 fusion peptides and the antiproteolytic feature extends to other therapeutic peptide templates, such as the diabetes drug exenatide (Byetta). Thus, hydrocarbon double-stapling may unlock the therapeutic potential of natural bioactive polypeptides by transforming them into structurally fortified agents with enhanced bioavailability. PMID:20660316

From amino acid sequence to bioactivity: The biomedical potential of antitumor peptides.

PubMed

Blanco-Míguez, Aitor; Gutiérrez-Jácome, Alberto; Pérez-Pérez, Martín; Pérez-Rodríguez, Gael; Catalán-García, Sandra; Fdez-Riverola, Florentino; Lourenço, Anália; Sánchez, Borja

2016-06-01

Chemoprevention is the use of natural and/or synthetic substances to block, reverse, or retard the process of carcinogenesis. In this field, the use of antitumor peptides is of interest as, (i) these molecules are small in size, (ii) they show good cell diffusion and permeability, (iii) they affect one or more specific molecular pathways involved in carcinogenesis, and (iv) they are not usually genotoxic. We have checked the Web of Science Database (23/11/2015) in order to collect papers reporting on bioactive peptide (1691 registers), which was further filtered searching terms such as "antiproliferative," "antitumoral," or "apoptosis" among others. Works reporting the amino acid sequence of an antiproliferative peptide were kept (60 registers), and this was complemented with the peptides included in CancerPPD, an extensive resource for antiproliferative peptides and proteins. Peptides were grouped according to one of the following mechanism of action: inhibition of cell migration, inhibition of tumor angiogenesis, antioxidative mechanisms, inhibition of gene transcription/cell proliferation, induction of apoptosis, disorganization of tubulin structure, cytotoxicity, or unknown mechanisms. The main mechanisms of action of those antiproliferative peptides with known amino acid sequences are presented and finally, their potential clinical usefulness and future challenges on their application is discussed. © 2016 The Protein Society.

From amino acid sequence to bioactivity: The biomedical potential of antitumor peptides

PubMed Central

Blanco‐Míguez, Aitor; Gutiérrez‐Jácome, Alberto; Pérez‐Pérez, Martín; Pérez‐Rodríguez, Gael; Catalán‐García, Sandra; Fdez‐Riverola, Florentino; Lourenço, Anália

2016-01-01

Abstract Chemoprevention is the use of natural and/or synthetic substances to block, reverse, or retard the process of carcinogenesis. In this field, the use of antitumor peptides is of interest as, (i) these molecules are small in size, (ii) they show good cell diffusion and permeability, (iii) they affect one or more specific molecular pathways involved in carcinogenesis, and (iv) they are not usually genotoxic. We have checked the Web of Science Database (23/11/2015) in order to collect papers reporting on bioactive peptide (1691 registers), which was further filtered searching terms such as “antiproliferative,” “antitumoral,” or “apoptosis” among others. Works reporting the amino acid sequence of an antiproliferative peptide were kept (60 registers), and this was complemented with the peptides included in CancerPPD, an extensive resource for antiproliferative peptides and proteins. Peptides were grouped according to one of the following mechanism of action: inhibition of cell migration, inhibition of tumor angiogenesis, antioxidative mechanisms, inhibition of gene transcription/cell proliferation, induction of apoptosis, disorganization of tubulin structure, cytotoxicity, or unknown mechanisms. The main mechanisms of action of those antiproliferative peptides with known amino acid sequences are presented and finally, their potential clinical usefulness and future challenges on their application is discussed. PMID:27010507

The enzymatic hydrolysis of soy protein isolate by Corolase PP under high hydrostatic pressure and its effect on bioactivity and characteristics of hydrolysates.

PubMed

Guan, Haining; Diao, Xiaoqin; Jiang, Fan; Han, Jianchun; Kong, Baohua

2018-04-15

Enzymatic hydrolysis of soy protein isolate by Corolase PP under high hydrostatic pressure conditions was studied and the effects of hydrolysis on antioxidant and antihypertensive activities were investigated. As observed, high hydrostatic pressure (80-300MPa) enhanced the hydrolytic efficiency of Corolase PP and decreased the surface hydrophobicity of the hydrolysates. Hydrolysates obtained at 200MPa for 4h had higher bioactivities (reducing power, ABTS radical-scavenging and ACE inhibitory activities). The molecular weight (MW) determination indicated that hydrolysis at high hydrostatic pressure could increase the production of small peptides (<3kDa) and the amino acid sequences of these peptides with different inhibitory abilities, less than 3kDa, in hydrolysates were identified using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI TOF MS). These results indicated that high hydrostatic pressure combined with Corolase PP treatments could be used as a potential technology to produce bioactive peptides from soy protein isolate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Screening Method for the Discovery of Potential Bioactive Cysteine-Containing Peptides Using 3D Mass Mapping

NASA Astrophysics Data System (ADS)

van Oosten, Luuk N.; Pieterse, Mervin; Pinkse, Martijn W. H.; Verhaert, Peter D. E. M.

2015-12-01

Animal venoms and toxins are a valuable source of bioactive peptides with pharmacologic relevance as potential drug leads. A large subset of biologically active peptides discovered up till now contain disulfide bridges that enhance stability and activity. To discover new members of this class of peptides, we developed a workflow screening specifically for those peptides that contain inter- and intra-molecular disulfide bonds by means of three-dimensional (3D) mass mapping. Two intrinsic properties of the sulfur atom, (1) its relatively large negative mass defect, and (2) its isotopic composition, allow for differentiation between cysteine-containing peptides and peptides lacking sulfur. High sulfur content in a peptide decreases the normalized nominal mass defect (NMD) and increases the normalized isotopic shift (NIS). Hence in a 3D plot of mass, NIS, and NMD, peptides with sulfur appear in this plot with a distinct spatial localization compared with peptides that lack sulfur. In this study we investigated the skin secretion of two frog species; Odorrana schmackeri and Bombina variegata. Peptides from the crude skin secretions were separated by nanoflow LC, and of all eluting peptides high resolution zoom scans were acquired in order to accurately determine both monoisotopic mass and average mass. Both the NMD and the NIS were calculated from the experimental data using an in-house developed MATLAB script. Candidate peptides exhibiting a low NMD and high NIS values were selected for targeted de novo sequencing, and this resulted in the identification of several novel inter- and intra-molecular disulfide bond containing peptides.

The role of peptides derived from Spirulina maxima in downregulation of FcεRI-mediated allergic responses.

PubMed

Vo, Thanh-Sang; Ngo, Dai-Hung; Kang, Kyong-Hwa; Park, Sun-Joo; Kim, Se-Kwon

2014-11-01

Spirulina has been found suitable for use as a bioactive additive. It is an excellent source of protein that can be hydrolyzed into bioactive peptides. Two peptides LDAVNR (P1) and MMLDF (P2) purified from enzymatic hydrolysate of Spirulina maxima have been reported to be effective against early atherosclerotic responses. In this study, the intracellular mechanism involved in the downregulation of these peptides on high-affinity IgE receptor-mediated allergic reaction was further investigated. RBL-2H3 mast cells were pretreated with P1 or P2 and sensitized with dinitrophenyl-specific IgE antibody before stimulation of antigen dinitrophenyl-BSA. It was revealed that P1 and P2 exhibited significant inhibition on mast-cell degranulation via decreasing histamine release and intracellular Ca(2+) elevation. The inhibitory activity of P1 was found due to blockade of calcium- and microtubule-dependent signaling pathways. Meanwhile, the inhibition of P2 was involved in suppression of phospholipase Cγ activation and reactive oxygen species production. Moreover, the suppressive effects of P1 and P2 on generation of IL-4 were evidenced via depression of nuclear factor-κB translocation. These findings indicate that peptides P1 and P2 from S. maxima may be promising candidates of antiallergic therapeutics, contributing to development of bioactive food ingredients for amelioration of allergic diseases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Soluble expression and purification of the recombinant bioactive peptide precursor BPP-1 in Escherichia coli using a cELP-SUMO dual fusion system.

PubMed

Rao, Shengqi; Zang, Xiangyu; Yang, Zhenquan; Gao, Lu; Yin, Yongqi; Fang, Weiming

2016-02-01

A bioactive peptide precursor (BPP-1, 14.3 kDa/115AA), a newly designed polypeptide that may exert a potential antihypertensive effect in vivo, is composed of many different ACE inhibitory peptides and antioxidant peptides tandemly linked according to the restriction sites of gastrointestinal proteases. In this report, we present a novel method to obtain soluble BPP-1 in Escherichia coli using cationic elastin-like polypeptide and SUMO (cELP-SUMO) tags. The cELP-SUMO-tagged fusion protein was expressed in soluble form at 20 °C for 20 h. After purification based on the inverse transition cycling (ITC) method, the purified cELP-SUMO-CFPP fusion protein was subsequently cleaved by a SUMO protease to release the mature BPP-1. After a subsequent simple salt precipitation process, approximately 167.2 mg of recombinant BPP-1 was obtained from 1 l of bacterial culture with at least 92% purity. The molecular mass (Mr) of the recombinant BPP-1 was confirmed by MALDI-TOF MS to equal 14,347. The purified BPP-1 was subjected to simulated gastrointestinal digestion, and the resulting hydrolysates exhibited notable ACE inhibitory and antioxidant activities in vitro. This report provides the first description of the soluble production of a bioactive peptide multimer with potential ACE inhibitory and antioxidant activities in E. coli using a cELP-SUMO tag. Copyright © 2015 Elsevier Inc. All rights reserved.

Hybridization between the African clawed frogs Xenopus laevis and Xenopus muelleri (Pipidae) increases the multiplicity of antimicrobial peptides in skin secretions of female offspring.

PubMed

Mechkarska, Milena; Meetani, Mohammed; Michalak, Pawel; Vaksman, Zalman; Takada, Koji; Conlon, J Michael

2012-09-01

Peptidomic analysis was used to compare the distribution of host-defense peptides in norepinephrine-stimulated skin secretions from laboratory-generated female F1 hybrids of the common clawed frog Xenopus laevis (Daudin, 1802) and Mueller's clawed frog Xenopus muelleri (Peters, 1844) with the corresponding distribution in skin secretions from the parent species. A total of 18 peptides were identified in secretions from the hybrid frogs. Eleven peptides (magainin-1, magainin-2, CPF-1, CPF-3, CPF-4, CPF-5, CPF-6, CPF-7, XPF-1, XPF-2, and PGLa) were identified in secretions of both the hybrids and X. laevis. Four peptides (magainin-M1, XPF-M1, CPF-M1, and tigerinin-M1) were previously found in skin secretions of X. muelleri but magainin-M2 and CPF-M2 from X. muelleri were not detected. Three previously undescribed peptides (magainin-LM1, PGLa-LM1, and CPF-LM1) were purified from the secretions of the hybrid frogs that were not detected in secretions from either X. laevis or X. muelleri. Magainin-LM1 differs from magainin-2 from X. laevis by a single amino acid substitution (Gly(13)→Ala) but PGLa-LM1 and CPF-LM1 differ appreciably in structure from orthologs in the parent species. CPF-LM1 shows potent, broad-spectrum antimicrobial activity and is hemolytic. The data indicate that hybridization increases the multiplicity of skin host-defense peptides in skin secretions. As the female F1 hybrids are fertile, hybridization may represent an adaptive strategy among Xenopus species to increase protection against pathogenic microorganisms in the environment. Copyright © 2012 Elsevier Inc. All rights reserved.

Neuropeptide tyrosine (NPY)--a major cardiac neuropeptide.

PubMed

Gu, J; Polak, J M; Adrian, T E; Allen, J M; Tatemoto, K; Bloom, S R

1983-05-07

A newly discovered bioactive peptide, neuropeptide tyrosine (NPY), has been found in the human cardiac nervous system. Dense concentrations of NPY-immunoreactive nerve fibres were found in association with nodal tissue (atrioventricular node 22.1 +/- 3.7 pmol/g). NPY nerve fibres were seen in close contact with cardiac muscle fibres and were also found around the coronary vessels (19.6 +/- 6.2 pmol/g). Analysis of the peptide by high-performance liquid chromatography demonstrated that it was present in a single molecular form, closely similar or identical to that of the isolated bioactive peptide. Cardiac function in man has long been known to be influenced by cholinergic and adrenergic nerves. There now appears to be a further component of the nervous system in the human heart, involving peptidergic nerves containing NPY.

Biomimicry of surfactant protein C.

PubMed

Brown, Nathan J; Johansson, Jan; Barron, Annelise E

2008-10-01

Since the widespread use of exogenous lung surfactant to treat neonatal respiratory distress syndrome, premature infant survival and respiratory morbidity have dramatically improved. Despite the effectiveness of the animal-derived surfactant preparations, there still remain some concerns and difficulties associated with their use. This has prompted investigation into the creation of synthetic surfactant preparations. However, to date, no clinically used synthetic formulation is as effective as the natural material. This is largely because the previous synthetic formulations lacked analogues of the hydrophobic proteins of the lung surfactant system, SP-B and SP-C, which are critical functional constituents. As a result, recent investigation has turned toward the development of a new generation of synthetic, biomimetic surfactants that contain synthetic phospholipids along with a mimic of the hydrophobic protein portion of lung surfactant. In this Account, we detail our efforts in creating accurate mimics of SP-C for use in a synthetic surfactant replacement therapy. Despite SP-C's seemingly simple structure, the predominantly helical protein is extraordinarily challenging to work with given its extreme hydrophobicity and structural instability, which greatly complicates the creation of an effective SP-C analogue. Drawing inspiration from Nature, two promising biomimetic approaches have led to the creation of rationally designed biopolymers that recapitulate many of SP-C's molecular features. The first approach utilizes detailed SP-C structure-activity relationships and amino acid folding propensities to create a peptide-based analogue, SP-C33. In SP-C33, the problematic and metastable polyvaline helix is replaced with a structurally stable polyleucine helix and includes a well-placed positive charge to prevent aggregation. SP-C33 is structurally stable and eliminates the association propensity of the native protein. The second approach follows the same design considerations but makes use of a non-natural, poly-N-substituted glycine or "peptoid" scaffold to circumvent the difficulties associated with SP-C. By incorporating unique biomimetic side chains in a non-natural backbone, the peptoid mimic captures both SP-C's hydrophobic patterning and its helical secondary structure. Despite the differences in structure, both SP-C33 and the SP-C peptoid mimic capture many requisite features of SP-C. In a surfactant environment, these analogues also replicate many of the key surface activities necessary for a functional biomimetic surfactant therapy while overcoming the difficulties associated with the natural protein. With improved stability, greater production potential, and elimination of possible pathogenic contamination, these biomimetic surfactant formulations offer not only the potential to improve the treatment of respiratory distress syndrome but also the opportunity to treat other respiratory-related disorders.

Conformational analysis of a synthetic fish kisspeptin 1 peptide in membrane mimicking environments

PubMed Central

Shahi, Neetu; Singh, Atul Kumar; Khangembam, Victoria Chanu; Singh, Arvind Kumar; Kumar, Satish

2017-01-01

Kisspeptin 1 is a neuropeptide hormone of the RFamide family, which act as an upstream regulator of brain-pituitary-gonad (BPG) axis in most vertebrates including teleosts. In the present study, a 16 amino acid long putative mature bioactive peptide (kiss 1) from preprokisspeptin 1 of golden mahseer, Tor putitora (Hamilton, 1822), was synthesized and characterized using an integrated (experimental and in silico) approach. The far-UV circular dichroism (CD) spectrum of this peptide was evaluated both in aqueous and membrane mimicking solvents (TFE, HFIP and Dioxane). The results indicate that kiss 1 peptide adopted helical, turn and β conformations in membrane like environments. The near-UV CD spectroscopy was also carried out to examine the tertiary packing around aromatic residues of kiss 1 peptide and the peptide-membrane complex. The kiss 1 peptide exhibited little signal in water, but a prominent negative band was observed at around 275 nm when membrane mimetic solution was added. The observed ordered conformations of kiss 1 peptide in the different solvents indicated its potential biological activity which could enhance the secretion of gonadotropin-releasing hormone (GnRH) at BPG axis. The conformational information generated from the present study reinforces the application prospects of bioactive synthetic peptide analogs of kisspeptin 1 in improving the reproductive performances of important cultivable fish species. PMID:28977030

Cyanobactins from Cyanobacteria: Current Genetic and Chemical State of Knowledge

PubMed Central

Martins, Joana; Vasconcelos, Vitor

2015-01-01

Cyanobacteria are considered to be one of the most promising sources of new, natural products. Apart from non-ribosomal peptides and polyketides, ribosomally synthesized and post-translationally modified peptides (RiPPs) are one of the leading groups of bioactive compounds produced by cyanobacteria. Among these, cyanobactins have sparked attention due to their interesting bioactivities and for their potential to be prospective candidates in the development of drugs. It is assumed that the primary source of cyanobactins is cyanobacteria, although these compounds have also been isolated from marine animals such as ascidians, sponges and mollusks. The aim of this review is to update the current knowledge of cyanobactins, recognized as being produced by cyanobacteria, and to emphasize their genetic clusters and chemical structures as well as their bioactivities, ecological roles and biotechnological potential. PMID:26580631

Bioactive Hybrid Particles from Poly(D,L-lactide-co-glycolide) Nanoparticle Stabilized Lipid Droplets.

PubMed

Joyce, Paul; Whitby, Catherine P; Prestidge, Clive A

2015-08-12

Biodegradable and bioactive hybrid particles composed of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles and medium-chain triglycerides were prepared by spray drying lipid-in-water emulsions stabilized by PLGA nanoparticles, to form PLGA-lipid hybrid (PLH) microparticles approximately 5 μm in mean diameter. The nanoparticle stabilizer was varied and mannitol was also incorporated during the preparation to investigate the effect of stabilizer charge and cryoprotectant content on the particle microstructure. An in vitro lipolysis model was used to demonstrate the particles' bioactivity by manipulating the digestion kinetics of encapsulated lipid by pancreatic lipase in simulated gastrointestinal fluid. Lipid digestion kinetics were enhanced in PLH and PLGA-lipid-mannitol hybrid (PLMH) microparticles for both stabilizers, compared to a coarse emulsion, in biorelevant media. An optimal digestion rate was observed for the negatively charged PLMH system, evidenced by a 2-fold increase in the pseudo-first-order rate constant compared to a coarse emulsion. Improved microparticle redispersion, probed by dual dye confocal fluorescence microscopy, increased the available surface area of lipid for lipase adsorption, enhancing digestion kinetics. Thereby, lipase action was controlled in hybrid microparticles by altering the surface charge and carbohydrate content. Our results demonstrate that bioactive microparticles composed of versatile and biodegradable polymeric particles and oil droplets have great potential for use in smart food and nutrient delivery, as well as safer and more efficacious oral delivery of drugs and drug combinations.

Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials.

PubMed

Montalbano, Giorgia; Fiorilli, Sonia; Caneschi, Andrea; Vitale-Brovarone, Chiara

2018-04-28

Bone tissue engineering offers an alternative promising solution to treat a large number of bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario, the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able to perform a sol-gel transition under physiological conditions. Field emission scanning electron microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate deposition. The high-water content promoted the strontium ion release from the embedded glass particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the suspension printability was assessed by means of rheological studies and preliminary extrusion tests, showing shear thinning and fast material recovery upon deposition. In conclusion, the reported results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone tissue engineering have been developed.

Materials and methods for stabilizing nanoparticles in salt solutions

DOEpatents

Robinson, David Bruce; Zuckermann, Ronald; Buffleben, George M.

2013-06-11

Sequence-specific polymers are proving to be a powerful approach to assembly and manipulation of matter on the nanometer scale. Ligands that are peptoids, or sequence-specific N-functional glycine oligomers, allow precise and flexible control over the arrangement of binding groups, steric spacers, charge, and other functionality. We have synthesized short peptoids that can prevent the aggregation of gold nanoparticles in high-salt environments including divalent salt, and allow co-adsorption of a single DNA molecule. This degree of precision and versatility is likely to prove essential in bottom-up assembly of nanostructures and in biomedical applications of nanomaterials.

Enabling techniques in the search for new antibiotics: Combinatorial biosynthesis of sugar-containing antibiotics.

PubMed

Park, Je Won; Nam, Sang-Jip; Yoon, Yeo Joon

2017-06-15

Nature has a talent for inventing a vast number of natural products, including hybrids generated by blending different scaffolds, resulting in a myriad of bioactive chemical entities. Herein, we review the highlights and recent trends (2010-2016) in the combinatorial biosynthesis of sugar-containing antibiotics where nature's structural diversification capabilities are exploited to enable the creation of new anti-infective and anti-proliferative drugs. In this review, we describe the modern combinatorial biosynthetic approaches for polyketide synthase-derived complex and aromatic polyketides, non-ribosomal peptide synthetase-directed lipo-/glycopeptides, aminoglycosides, nucleoside antibiotics, and alkaloids, along with their therapeutic potential. Finally, we present the feasible nexus between combinatorial biosynthesis, systems biology, and synthetic biology as a toolbox to provide new antibiotics that will be indispensable in the post-antibiotic era. Copyright © 2016 Elsevier Inc. All rights reserved.

Nocardiopsis species: a potential source of bioactive compounds.

PubMed

Bennur, T; Ravi Kumar, A; Zinjarde, S S; Javdekar, V

2016-01-01

Members of the genus Nocardiopsis are an ecologically versatile and biotechnologically important group of Actinomycetes. Most of the isolates are halotolerant or halophilic and they prevail in soils, marine environments or hypersaline locations. To aid their survival under these conditions, they mainly produce extremozymes, compatible solutes, surfactants and bioactive compounds. The current review details the bioactive compounds obtained for this genus. Important antimicrobial agents obtained from this genus include polyketides, phenzines, quinoline alkaloids, terphenyls, proteins, thiopeptides and amines. Polyketides and peptides displaying potent anticancer activities are also significant. Tumour promoting agents, P-glycoprotein (P-gp) inhibitors, immunomodulators and protein kinase inhibitors are other relevant products obtained from Nocardiopsis species. Structurally, polyketides (synthesized by polyketide synthases) and peptides (made by nonribosomal peptide synthetases or cyclodipeptide synthases) are important compounds. Considered here are also toxins, anti photoaging and adipogenic agents produced by this genus. The gene clusters mediating the synthesis of bioactive compounds have been described. Commercially available products (Apoptolidins and K-252a) derived from this genus have also been described. This review highlights the significance of a single genus in producing an assortment of compounds with varied biological activities. On account of these features, the members of this genus have established a place for themselves and are of considerable value in producing compounds with profound bio-medical applications. © 2015 The Society for Applied Microbiology.

[The antihypertensive effect of fermented milks].

PubMed

Domínguez González, Karina N; Cruz Guerrero, Alma E; Márquez, Humberto González; Gómez Ruiz, Lorena C; García-Garibay, Mariano; Rodríguez Serrano, Gabriela M

2014-01-01

There is a great variety of fermented milks containing lactic acid bacteria that present health-promoting properties. Milk proteins are hydrolyzed by the proteolytic system of these microorganisms producing peptides which may also perform other functions in vivo. These peptides are encrypted within the primary structure of proteins and can be released through food processing, either by milk fermentation or enzymatic hydrolysis during gastrointestinal transit. They perform different activities, since they act in the cardiovascular, digestive, endocrine, immune and nervous systems. Bioactive peptides that have an antihypertensive, antithrombotic, antioxidant and hypocholesterolemic effect on the cardiovascular system can reduce the risk factors for chronic disease manifestation and help improve human health. Most studied bioactive peptides are those which exert an antihypertensive effect by inhibiting the angiotensin-converting enzyme (ACE). Recently, the study of these peptides has focused on the implementation of tests to prove that they have an effect on health. This paper focuses on the production of ACEinhibitory antihypertensive peptides from fermented milks, its history, production and in vivo tests on rats and humans, on which its hypotensive effect has been shown. Copyright © 2014 Asociación Argentina de Microbiología. Publicado por Elsevier España. All rights reserved.

Biochemical and metabolic mechanisms by which dietary whey protein may combat obesity and Type 2 diabetes.

PubMed

Jakubowicz, Daniela; Froy, Oren

2013-01-01

Consumption of milk and dairy products has been associated with reduced risk of metabolic disorders and cardiovascular disease. Milk contains two primary sources of protein, casein (80%) and whey (20%). Recently, the beneficial physiological effects of whey protein on the control of food intake and glucose metabolism have been reported. Studies have shown an insulinotropic and glucose-lowering properties of whey protein in healthy and Type 2 diabetes subjects. Whey protein seems to induce these effects via bioactive peptides and amino acids generated during its gastrointestinal digestion. These amino acids and peptides stimulate the release of several gut hormones, such as cholecystokinin, peptide YY and the incretins gastric inhibitory peptide and glucagon-like peptide 1 that potentiate insulin secretion from β-cells and are associated with regulation of food intake. The bioactive peptides generated from whey protein may also serve as endogenous inhibitors of dipeptidyl peptidase-4 (DPP-4) in the proximal gut, preventing incretin degradation. Indeed, recently, DPP-4 inhibitors were identified in whey protein hydrolysates. This review will focus on the emerging properties of whey protein and its potential clinical application for obesity and Type 2 diabetes. Copyright © 2013 Elsevier Inc. All rights reserved.

Chemopreventive role of food-derived proteins and peptides: A review.

PubMed

Hernández-Ledesma, Blanca; Hsieh, Chia-Chien

2017-07-24

Cancer is one of the leading causes of mortality and disability worldwide. Although great advances in cancer treatments such as chemotherapy, surgery, and radiation are currently being achieved, their application is associated with numerous and expensive adverse side effects. Epidemiological evidence has demonstrated that the consumption of certain foods potentially prevents up to 35% of cancer cases. Bioactive components are ubiquitous in nature, also in dietary food, providing an essential link in health maintenance, promotion, and prevention of chronic diseases, such as cancer. Development of bioactive proteins and peptides is a current and innovative strategy for cancer prevention/cure. A growing body of anticancer protein and peptides from natural sources has shown the ability to reduce tumor progression through multiple mechanisms including apoptotic, antiproliferative, antiangiogenic, and immunomodulatory activities. This review is focused on proteins and peptides from different food sources including plants, milk, egg, and marine organisms in which chemopreventive properties have been demonstrated. Other aspects such as mechanism of action, bioavailability, and identification and characterization of food-derived peptides by advance separated technologies are also included. This review highlights the potential application of food-derived peptides as functional food ingredients and pharmaceutical candidates in the auxiliary therapy of cancer.

Release of bioactive peptides from polyurethane films in vitro and in vivo: Effect of polymer composition.

PubMed

Zhang, Jing; Woodruff, Trent M; Clark, Richard J; Martin, Darren J; Minchin, Rodney F

2016-09-01

Thermoplastic polyurethanes (TPUs) are widely used in biomedical applications due to their excellent biocompatibility. Their role as matrices for the delivery of small molecule therapeutics has been widely reported. However, very little is known about the release of bioactive peptides from this class of polymers. Here, we report the release of linear and cyclic peptides from TPUs with different hard and soft segments. Solvent casting of the TPU at room temperature mixed with the different peptides resulted in reproducible efflux profiles with no evidence of drug degradation. Peptide release was dependent on the size as well as the composition of the TPU. Tecoflex 80A (T80A) showed more extensive release than ElastEon 5-325, which correlated with a degree of hydration. It was also shown that the composition of the medium influenced the rate and extent of peptide efflux. Blending the different TPUs allowed for better control of peptide efflux, especially the initial burst effect. Peptide-loaded TPU prolonged the plasma levels of the anti-inflammatory cyclic peptide PMX53, which normally has a plasma half-life of less than 30min. Using a blend of T80A and E5-325, therapeutic plasma levels of PMX53 were observed up to 9days following a single intraperitoneal implantation of the drug-loaded film. PMX53 released from the blended TPUs significantly inhibited B16-F10 melanoma tumor growth in mice demonstrating its bioactivity in vivo. This study provides important findings for TPU-based therapeutic peptide delivery that could improve the pharmacological utility of peptides as therapeutics. Therapeutic peptides can be highly specific and potent pharmacological agents, but are poorly absorbed and rapidly degraded in the body. This can be overcome by using a matrix that protects the peptide in vivo and promotes its slow release so that a therapeutic effect can be achieved over days or weeks. Thermoplastic polyurethanes are a versatile family of polymers that are biocompatible and used for medical implants. Here, the release of several peptides from a range of polyurethanes was shown to depend on the type of polymer used in the polyurethane. This is the first study to examine polyurethane blends for peptide delivery and shows that the rate and extent of peptide release can be fine-tuned using different hard and soft segment mixtures in the polymer. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Ultra-high-pressure processing improves proteolysis and release of bioactive peptides with activation activities on alcohol metabolic enzymes in vitro from mushroom foot protein.

PubMed

Zhao, Rui-Jie; Huo, Chun-Yan; Qian, Yang; Ren, Di-Feng; Lu, Jun

2017-09-15

This study was to find an effective process to extract bioactive peptides from mushroom foot and determine their effects on activation of alcohol metabolic enzymes in vitro. The optimum extraction assisted by ultra-high-pressure processing of mushroom foot peptides was obtained with a pressure of 400MPa and a processing time of 10min. After ultrafiltration, peptides with molecular weight of 0-3kDa had the highest activity to activate alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) by 70.79% and 71.35%, respectively. Following dextran gel chromatography, two peaks (p-I and p-II) appeared and the activation activities on ADH and ALDH of p-I were 72.00% and 73.43%, both higher than p-II. Nine peptides were found in p-I as determined by LC-MS/MS, and two of them (IPLH and IPIVLL) were synthesized. IPLH activated ADH and ALDH by 42.7% and 29.2% respectively, which were higher than IPIVLL. Copyright © 2017 Elsevier Ltd. All rights reserved.

Three molecular forms of atrial natriuretic peptides: quantitative analysis and biological characterization.

PubMed

Nagai-Okatani, Chiaki; Kangawa, Kenji; Minamino, Naoto

2017-07-01

Atrial natriuretic peptide (ANP) is primarily produced in the heart tissue and plays a pivotal role in maintaining cardiovascular homeostasis in endocrine and autocrine/paracrine systems and has clinical applications as a biomarker and a therapeutic agent for cardiac diseases. ANP is synthesized by atrial cardiomyocytes as a preprohormone that is processed by a signal peptidase and stored in secretory granules as a prohormone. Subsequent proteolytic processing of ANP by corin during the secretion process results in a bioactive form consisting of 28 amino acid residues. Mechanical stretch of the atrial wall and multiple humoral factors directly stimulates the transcription and secretion of ANP. Secreted ANP elicits natriuretic and diuretic effects via cyclic guanosine monophosphate produced through binding to the guanylyl cyclase-A/natriuretic peptide receptor-A. Circulating ANP is subjected to rapid clearance by a natriuretic peptide receptor-C-mediated mechanism and proteolytic degradation by neutral endopeptidase. In humans, ANP is present as three endogenous molecular forms: bioactive α-ANP, a homodimer of α-ANP designated as β-ANP, and an ANP precursor designated as proANP (also referred to as γ-ANP). The proANP and especially β-ANP, as minor forms in circulation, are notably increased in patients with cardiac diseases, suggesting the utility of monitoring the pathophysiological conditions that result in abnormal proANP processing that cannot be monitored by inactive N-terminal proANP-related fragments. Emerging plate-based sandwich immunoassays for individual quantitation of the three ANP forms enables evaluation of diagnostic implications and net ANP bioactivity. This new tool may provide further understanding in the pathophysiology of cardiac diseases. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

An exhaustive survey of regular peptide conformations using a new metric for backbone handedness ( h )

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mannige, Ranjan V.

The Ramachandran plot is important to structural biology as it describes a peptide backbone in the context of its dominant degrees of freedom—the backbone dihedral anglesφandψ(Ramachandran, Ramakrishnan & Sasisekharan, 1963). Since its introduction, the Ramachandran plot has been a crucial tool to characterize protein backbone features. However, the conformation or twist of a backbone as a function ofφandψhas not been completely described for bothcisandtransbackbones. Additionally, little intuitive understanding is available about a peptide’s conformation simply from knowing theφandψvalues of a peptide (e.g., is the regular peptide defined byφ = ψ =  - 100°  left-handed or right-handed?). This report provides a new metric for backbone handednessmore » (h) based on interpreting a peptide backbone as a helix with axial displacementdand angular displacementθ, both of which are derived from a peptide backbone’s internal coordinates, especially dihedral anglesφ,ψandω. In particular,hequals sin(θ)d/d|, with range [-1, 1] and negative (or positive) values indicating left(or right)-handedness. The metrichis used to characterize the handedness of every region of the Ramachandran plot for bothcis(ω = 0°) and trans (ω = 180°) backbones, which provides the first exhaustive survey of twist handedness in Ramachandran (φ,ψ) space. These maps fill in the ‘dead space’ within the Ramachandran plot, which are regions that are not commonly accessed by structured proteins, but which may be accessible to intrinsically disordered proteins, short peptide fragments, and protein mimics such as peptoids. Finally, building on the work of (Zacharias & Knapp, 2013), this report presents a new plot based ondandθthat serves as a universal and intuitive alternative to the Ramachandran plot. The universality arises from the fact that the co-inhabitants of such a plot include every possible peptide backbone includingcisandtransbackbones. The intuitiveness arises from the fact thatdandθprovide, at a glance, numerous aspects of the backbone including compactness, handedness, and planarity.« less

An exhaustive survey of regular peptide conformations using a new metric for backbone handedness ( h )

DOE PAGES

Mannige, Ranjan V.

2017-05-16

The Ramachandran plot is important to structural biology as it describes a peptide backbone in the context of its dominant degrees of freedom—the backbone dihedral anglesφandψ(Ramachandran, Ramakrishnan & Sasisekharan, 1963). Since its introduction, the Ramachandran plot has been a crucial tool to characterize protein backbone features. However, the conformation or twist of a backbone as a function ofφandψhas not been completely described for bothcisandtransbackbones. Additionally, little intuitive understanding is available about a peptide’s conformation simply from knowing theφandψvalues of a peptide (e.g., is the regular peptide defined byφ = ψ =  - 100°  left-handed or right-handed?). This report provides a new metric for backbone handednessmore » (h) based on interpreting a peptide backbone as a helix with axial displacementdand angular displacementθ, both of which are derived from a peptide backbone’s internal coordinates, especially dihedral anglesφ,ψandω. In particular,hequals sin(θ)d/d|, with range [-1, 1] and negative (or positive) values indicating left(or right)-handedness. The metrichis used to characterize the handedness of every region of the Ramachandran plot for bothcis(ω = 0°) and trans (ω = 180°) backbones, which provides the first exhaustive survey of twist handedness in Ramachandran (φ,ψ) space. These maps fill in the ‘dead space’ within the Ramachandran plot, which are regions that are not commonly accessed by structured proteins, but which may be accessible to intrinsically disordered proteins, short peptide fragments, and protein mimics such as peptoids. Finally, building on the work of (Zacharias & Knapp, 2013), this report presents a new plot based ondandθthat serves as a universal and intuitive alternative to the Ramachandran plot. The universality arises from the fact that the co-inhabitants of such a plot include every possible peptide backbone includingcisandtransbackbones. The intuitiveness arises from the fact thatdandθprovide, at a glance, numerous aspects of the backbone including compactness, handedness, and planarity.« less

Polyglutamate directed coupling of bioactive peptides for the delivery of osteoinductive signals on allograft bone

PubMed Central

Culpepper, Bonnie K.; Bonvallet, Paul P.; Reddy, Michael S.; Ponnazhagan, Selvarangan; Bellis, Susan L.

2012-01-01

Allograft bone is commonly used as an alternative to autograft, however allograft lacks many osteoinductive factors present in autologous bone due to processing. In this study, we investigated a method to reconstitute allograft with osteoregenerative factors. Specifically, an osteoinductive peptide from collagen I, DGEA, was engineered to express a heptaglutamate (E7) domain, which binds the hydroxyapatite within bone mineral. Addition of E7 to DGEA resulted in 9× greater peptide loading on allograft, and significantly greater retention after a 5-day interval with extensive washing. When factoring together greater initial loading and retention, the E7 domain directed a 45-fold enhancement of peptide density on the allograft surface. Peptide-coated allograft was also implanted subcutaneously into rats and it was found that E7DGEA was retained in vivo for at least 3 months. Interestingly, E7DGEA peptides injected intravenously accumulated within bone tissue, implicating a potential role for E7 domains in drug delivery to bone. Finally, we determined that, as with DGEA, the E7 modification enhanced coupling of a bioactive BMP2-derived peptide on allograft. These results suggest that E7 domains are useful for coupling many types of bone-regenerative molecules to the surface of allograft to reintroduce osteoinductive signals and potentially advance allograft treatments. PMID:23182349

Degradation of milk-based bioactive peptides by yogurt fermentation bacteria.

PubMed

Paul, M; Somkuti, G A

2009-09-01

To analyse the effect of cell-associated peptidases in yogurt starter culture strains Lactobacillus delbrueckii ssp. bulgaricus (LB) and Streptococcus thermophilus (ST) on milk-protein-based antimicrobial and hypotensive peptides in order to determine their survival in yogurt-type dairy foods. The 11mer antimicrobial and 12mer hypotensive milk-protein-derived peptides were incubated with mid-log cells of LB and ST, which are required for yogurt production. Incubations were performed at pH 4.5 and 7.0, and samples removed at various time points were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC). The peptides remained mostly intact at pH 4.5 in the presence of ST strains and moderately digested by exposure to LB cells. Peptide loss occurred more rapidly and was more extensive after incubation at pH 7.0. The 11mer and 12mer bioactive peptides may be added at the end of the yogurt-making process when the pH level has dropped to 4.5, limiting the overall extent of proteolysis. The results show the feasibility of using milk-protein-based antimicrobial and hypotensive peptides as food supplements to improve the health-promoting qualities of liquid and semi-solid dairy foods prepared by the yogurt fermentation process.

Synthesis of novel quaternary silica hybrid bioactive microspheres.

PubMed

Angelopoulou, A; Efthimiadou, E Κ; Kordas, G

2018-01-01

To survey the preparation of novel hybrid microspheres of quaternary silicate glassy composition (SiO 2 P 2 O 5 CaONa 2 O) and the prospect of using them as an osteogenic system with enhanced bioactive properties for the development of hydroxyapatite. In line with our previous synthetic procedure a two-step process was followed, wherein polystyrene (PS) microspheres were prepared by the emulsifier free-emulsion polymerization method and constituted the core for the sol-gel coating of the silicate inorganic shell. The development of the hybrid microspheres was based on silane and phosphate precursors and was assesses at different ratio of ethanol/water (of 9/1, 4/1, and 2/1, in mL) and at varied ammonia concentration of 4.8-1.0 mL. The hybrid microspheres had an average size ranged between 350 and 550 nm according to SEM, depending on the ethanol/water solution rate and ammonia content. The final microspheres probably exhibited a porous-like structure through the formation of diffused voids along with the low carbon content of the EDX analysis, which could be regulated by the catalyst content. The hybrid microspheres exhibited effective in vitro bioactivity assessed in simulated body fluids (SBF). Quaternary hybrid silica microspheres were effectively synthesized. The bioassay evaluation of the final microspheres revealed the rapid in vitro formation of a bone-like apatite layer. The results verify the bioactivity of the microspheres and promote further research of their suitability on regenerative treatment of bone abnormalities. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 112-120, 2018. © 2016 Wiley Periodicals, Inc.

Preparation of zeolite-A/chitosan hybrid composites and their bioactivities and antimicrobial activities.

PubMed

Yu, Liang; Gong, Jie; Zeng, Changfeng; Zhang, Lixiong

2013-10-01

Zeolite-A/chitosan hybrid composites with zeolite contents of 20-55 wt.% were prepared by in situ transformation of silica/chitosan mixtures in a sodium aluminate alkaline solution through impregnation-gelation-hydrothermal synthesis. The products were characterized by X-ray diffraction, diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, thermogravimetric analysis, and mercury penetration porosimetry. Their in vitro bioactivities were examined using as-synthesized and Ca(2+)-exchanged hybrid composites in simulated body fluid (SBF) for hydroxyapatite (HAP) growth. Their antimicrobial activities for Escherichia coli (E. coli) in trypticase soy broth (TSB) were evaluated using Ag(+)-exchanged hybrid composites. The zeolite-A/chitosan hybrid composites could be prepared as various shapes, including cylinders, plates and thin films. They possessed macropores with pore sizes ranging from 100 to 300 μm and showed compressive mechanical strength as high as 3.2 MPa when the zeolite content was 35 wt.%. Fast growth on the Ca(2+)-exchanged hybrid composites was observed with the highest weight gain of 51.4% in 30 days. The 35 wt.% Ag(+)-exchanged hybrid composite showed the highest antimicrobial activity, which could reduce the 9×10(6) CFU mL(-1)E. coli concentration to zero within 4h of incubation time with the Ag(+)-exchanged hybrid composite amount of 0.4 g L(-1). The bioactivity and antimicrobial activity could be combined by ion-exchanging the composites first with Ca(2+) and then with Ag(+). These zeolite-A/chitosan hybrid composites have potential applications on tissue engineering and antimicrobial food packaging. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of a large peptoid-DOTA combinatorial library.

PubMed

Singh, Jaspal; Lopes, Daniel; Gomika Udugamasooriya, D

2016-09-01

Conventional one-bead one-compound (OBOC) library synthesis is typically used to identify molecules with therapeutic value. The design and synthesis of OBOC libraries that contain molecules with imaging or even potentially therapeutic and diagnostic capacities (e.g. theranostic agents) has been overlooked. The development of a therapeutically active molecule with a built-in imaging component for a certain target is a daunting task, and structure-based rational design might not be the best approach. We hypothesize to develop a combinatorial library with potentially therapeutic and imaging components fused together in each molecule. Such molecules in the library can be used to screen, identify, and validate as direct theranostic candidates against targets of interest. As the first step in achieving that aim, we developed an on-bead library of 153,600 Peptoid-DOTA compounds in which the peptoids are the target-recognizing and potentially therapeutic components and the DOTA is the imaging component. We attached the DOTA scaffold to TentaGel beads using one of the four arms of DOTA, and we built a diversified 6-mer peptoid library on the remaining three arms. We evaluated both the synthesis and the mass spectrometric sequencing capacities of the test compounds and of the final library. The compounds displayed unique ionization patterns including direct breakages of the DOTA scaffold into two units, allowing clear decoding of the sequences. Our approach provides a facile synthesis method for the complete on-bead development of large peptidomimetic-DOTA libraries for screening against biological targets for the identification of potential theranostic agents in the future. © 2016 The Authors. Biopolymers Published by Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 673-684, 2016. © 2016 The Authors. Biopolymers Published by Wiley Periodicals, Inc.

A proteomic survey of nonribosomal peptide and polyketide biosynthesis in actinobacteria

USDA-ARS?s Scientific Manuscript database

Actinobacteria such as streptomycetes are renowned for their ability to produce bioactive natural products including nonribosomal peptides (NRPs) and polyketides (PKs). The advent of genome sequencing has revealed an even larger genetic repertoire for secondary metabolism with most of the small mole...

Milk Proteins, Peptides, and Oligosaccharides: Effects against the 21st Century Disorders

PubMed Central

Hsieh, Chia-Chien; Hernández-Ledesma, Blanca; Fernández-Tomé, Samuel; Weinborn, Valerie; Barile, Daniela; de Moura Bell, Juliana María Leite Nobrega

2015-01-01

Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn's development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed. PMID:25789308

Milk proteins, peptides, and oligosaccharides: effects against the 21st century disorders.

PubMed

Hsieh, Chia-Chien; Hernández-Ledesma, Blanca; Fernández-Tomé, Samuel; Weinborn, Valerie; Barile, Daniela; de Moura Bell, Juliana María Leite Nobrega

2015-01-01

Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn's development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed.

The bioactive acidic serine- and aspartate-rich motif peptide.

PubMed

Minamizaki, Tomoko; Yoshiko, Yuji

2015-01-01

The organic component of the bone matrix comprises 40% dry weight of bone. The organic component is mostly composed of type I collagen and small amounts of non-collagenous proteins (NCPs) (10-15% of the total bone protein content). The small integrin-binding ligand N-linked glycoprotein (SIBLING) family, a NCP, is considered to play a key role in bone mineralization. SIBLING family of proteins share common structural features and includes the arginine-glycine-aspartic acid (RGD) motif and acidic serine- and aspartic acid-rich motif (ASARM). Clinical manifestations of gene mutations and/or genetically modified mice indicate that SIBLINGs play diverse roles in bone and extraskeletal tissues. ASARM peptides might not be primary responsible for the functional diversity of SIBLINGs, but this motif is suggested to be a key domain of SIBLINGs. However, the exact function of ASARM peptides is poorly understood. In this article, we discuss the considerable progress made in understanding the role of ASARM as a bioactive peptide.

Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats.

PubMed

Ngo, Dai-Hung; Kang, Kyong-Hwa; Ryu, BoMi; Vo, Thanh-Sang; Jung, Won-Kyo; Byun, Hee-Guk; Kim, Se-Kwon

2015-05-01

The aim of this study was to investigate antihypertensive effect of bioactive peptides from skate (Okamejei kenojei) skin gelatin. The Alcalase/protease gelatin hydrolysate below 1 kDa (SAP) exhibited the highest angiotensin-I converting enzyme (ACE) inhibition compared to other hydrolysates. SAP can decrease systolic blood pressure significantly in spontaneously hypertensive rats. SAP inhibited vasoconstriction via PPAR-γ expression, activation and phosphorylation of eNOS in lungs. Moreover, the expression levels of endothelin-1, RhoA, α-smooth muscle actin, cleaved caspase 3 and MAPK were decreased by SAP in lungs. Vascularity, muscularization and cellular proliferation in lungs were detected by immunohistochemical staining. Finally, two purified peptides (LGPLGHQ, 720Da and MVGSAPGVL, 829Da) showed potent ACE inhibition with IC50 values of 4.22 and 3.09 μM, respectively. These results indicate that bioactive peptides isolated from skate skin gelatin may serve as candidates against hypertension and could be used as functional food ingredients. Copyright © 2014 Elsevier Ltd. All rights reserved.

Glutamic Acid Selective Chemical Cleavage of Peptide Bonds.

PubMed

Nalbone, Joseph M; Lahankar, Neelam; Buissereth, Lyssa; Raj, Monika

2016-03-04

Site-specific hydrolysis of peptide bonds at glutamic acid under neutral aqueous conditions is reported. The method relies on the activation of the backbone amide chain at glutamic acid by the formation of a pyroglutamyl (pGlu) imide moiety. This activation increases the susceptibility of a peptide bond toward hydrolysis. The method is highly specific and demonstrates broad substrate scope including cleavage of various bioactive peptides with unnatural amino acid residues, which are unsuitable substrates for enzymatic hydrolysis.

The Regulation of a Post-Translational Peptide Acetyltransferase: Strategies for Selectively Modifying the Biological Activity of Neural and Endocrine Peptides

DTIC Science & Technology

1988-02-01

quantitatively miror pathway. Only two of the enzymes which process 8-endorphin have been firmly identified, peptide acetyltransferase and... quantitatively minor. This implied that perhaps peptide acetyltransferase is not a critical determinant of the bioactivity of B-endorphin in brain. If so...provided us with a more difinitive understanding of the role of processing enzyme regulation in the overall biochemical and cellular response of the

Molecular basis of branched peptides resistance to enzyme proteolysis.

PubMed

Falciani, Chiara; Lozzi, Luisa; Pini, Alessandro; Corti, Federico; Fabbrini, Monica; Bernini, Andrea; Lelli, Barbara; Niccolai, Neri; Bracci, Luisa

2007-03-01

We found that synthetic peptides in the form of dendrimers become resistant to proteolysis. To determine the molecular basis of this resistance, different bioactive peptides were synthesized in monomeric, two-branched and tetra-branched form and incubated with human plasma and serum. Proteolytic resistance of branched multimeric sequences was compared to that of the same peptides synthesized as multimeric linear molecules. Unmodified peptides and cleaved sequences were detected by high pressure liquid chromatography and mass spectrometry. An increase in peptide copies did not increase peptide resistance in linear multimeric sequences, whereas multimericity progressively enhanced proteolytic stability of branched multimeric peptides. A structure-based hypothesis of branched peptide resistance to proteolysis by metallopeptidases is presented.

Bioactive compounds synthesized by non-ribosomal peptide synthetases and type-I polyketide synthases discovered through genome-mining and metagenomics.

PubMed

Nikolouli, Katerina; Mossialos, Dimitris

2012-08-01

Non-ribosomal peptide synthetases (NRPS) and type-I polyketide synthases (PKS-I) are multimodular enzymes involved in biosynthesis of oligopeptide and polyketide secondary metabolites produced by microorganisms such as bacteria and fungi. New findings regarding the mechanisms underlying NRPS and PKS-I evolution illustrate how microorganisms expand their metabolic potential. During the last decade rapid development of bioinformatics tools as well as improved sequencing and annotation of microbial genomes led to discovery of novel bioactive compounds synthesized by NRPS and PKS-I through genome-mining. Taking advantage of these technological developments metagenomics is a fast growing research field which directly studies microbial genomes or specific gene groups and their products. Discovery of novel bioactive compounds synthesized by NRPS and PKS-I will certainly be accelerated through metagenomics, allowing the exploitation of so far untapped microbial resources in biotechnology and medicine.

Antimicrobial Activity of Novel Synthetic Peptides Derived from Indolicidin and Ranalexin against Streptococcus pneumoniae

PubMed Central

Jindal, Hassan Mahmood; Le, Cheng Foh; Mohd Yusof, Mohd Yasim; Velayuthan, Rukumani Devi; Lee, Vannajan Sanghiran; Zain, Sharifuddin Md; Isa, Diyana Mohd; Sekaran, Shamala Devi

2015-01-01

Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics in order to defeat multidrug-resistant bacteria such as Streptococcus pneumoniae. In this study, thirteen antimicrobial peptides were designed based on two natural peptides indolicidin and ranalexin. Our results revealed that four hybrid peptides RN7-IN10, RN7-IN9, RN7-IN8, and RN7-IN6 possess potent antibacterial activity against 30 pneumococcal clinical isolates (MIC 7.81-15.62µg/ml). These four hybrid peptides also showed broad spectrum antibacterial activity (7.81µg/ml) against S. aureus, methicillin resistant S. aureus (MRSA), and E. coli. Furthermore, the time killing assay results showed that the hybrid peptides were able to eliminate S. pneumoniae within less than one hour which is faster than the standard drugs erythromycin and ceftriaxone. The cytotoxic effects of peptides were tested against human erythrocytes, WRL-68 normal liver cell line, and NL-20 normal lung cell line. The results revealed that none of the thirteen peptides have cytotoxic or hemolytic effects at their MIC values. The in silico molecular docking study was carried out to investigate the binding properties of peptides with three pneumococcal virulent targets by Autodock Vina. RN7IN6 showed a strong affinity to target proteins; autolysin, pneumolysin, and pneumococcal surface protein A (PspA) based on rigid docking studies. Our results suggest that the hybrid peptides could be suitable candidates for antibacterial drug development. PMID:26046345

Valorisation of tuna processing waste biomass for recovery of functional and antioxidant peptides using enzymatic hydrolysis and membrane fractionation process.

PubMed

Saidi, Sami; Ben Amar, Raja

2016-10-01

The enzymatic hydrolysis using Prolyve BS coupled to membrane process (Ultrafiltration (UF) and nanofiltration (NF)) is a means of biotransformation of tuna protein waste to Tuna protein hydrolysate (TPH) with higher added values. This method could be an effective solution for the production of bioactive compounds used in various biotechnological applications and minimizing the pollution problems generated by the seafood processing industries. The amino acid composition, functional and antioxidant properties of produced TPH were evaluated. The results show that the glutamic acid, aspartic acid, glycine, alaline, valine and leucine were the major amino acids detected in the TPH profile. After membrane fractionation process, those major amino acids were concentrated in the NF retentate (NFR). The NFR and NF permeate (NFP) have a higher protein solubility (>95 %) when compared to TPH (80 %). Higher oil and water binding capacity were observed in TPH and higher emulsifying and foam stability was found in UF retentate. The NFP showed the highest DPPH radical scavenging activity (65 %). The NFR contained antioxidant amino acid (30.3 %) showed the highest superoxide radical and reducing power activities. The TPH showed the highest iron chelating activity (75 %) compared to other peptide fractions. The effect of the membrane fractionation on the molecular weight distribution of the peptide and their bioactivities was underlined. We concluded that the TPH is a valuable source of bioactive peptides and their peptide fractions may serve as useful ingredients for application in food industry and formulation of nutritional products.

Enhancement of anti-tumor activity of hybrid peptide in conjugation with carboxymethyl dextran via disulfide linkers.

PubMed

Gaowa, Arong; Horibe, Tomohisa; Kohno, Masayuki; Tabata, Yasuhiko; Harada, Hiroshi; Hiraoka, Masahiro; Kawakami, Koji

2015-05-01

To improve the anti-tumor activity of EGFR2R-lytic hybrid peptide, we prepared peptide-modified dextran conjugates with the disulfide bonds between thiolated carboxymethyl dextran (CMD-Cys) and cysteine-conjugated peptide (EGFR2R-lytic-Cys). In vitro release studies showed that the peptide was released from the CMD-s-s-peptide conjugate in a concentration-dependent manner in the presence of glutathione (GSH, 2μM-2mM). The CMD-s-s-peptide conjugate exhibited a similar cytotoxic activity with free peptide alone against human pancreatic cancer BxPC-3 cells in vitro. Furthermore, it was shown that the CMD-s-s-peptide conjugates were highly accumulated in tumor tissue in a mouse xenograft model using BxPC-3 cells, and the anti-tumor activity of the conjugate was more effective than that of the free peptide. In addition, the plasma concentrations of peptide were moderately increased and the elimination half-life of the peptide was prolonged after intravenous injection of CMD-s-s-peptide conjugates. These results demonstrated that the conjugate based on thiolated CMD polymer would be potentially useful carriers for the sustained release of the hybrid peptide in vivo. Copyright © 2015 Elsevier B.V. All rights reserved.

Hexagonally Ordered Arrays of α-Helical Bundles Formed from Peptide-Dendron Hybrids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barkley, Deborah A.; Rokhlenko, Yekaterina; Marine, Jeannette E.

Combining monodisperse building blocks that have distinct folding properties serves as a modular strategy for controlling structural complexity in hierarchically organized materials. We combine an α-helical bundle-forming peptide with self-assembling dendrons to better control the arrangement of functional groups within cylindrical nanostructures. Site-specific grafting of dendrons to amino acid residues on the exterior of the α-helical bundle yields monodisperse macromolecules with programmable folding and self-assembly properties. The resulting hybrid biomaterials form thermotropic columnar hexagonal mesophases in which the peptides adopt an α-helical conformation. Bundling of the α-helical peptides accompanies self-assembly of the peptide-dendron hybrids into cylindrical nanostructures. The bundle stoichiometrymore » in the mesophase agrees well with the size found in solution for α-helical bundles of peptides with a similar amino acid sequence.« less

Reclaiming hijacked phagosomes: Hybrid nano-in-micro encapsulated MIAP peptide ensures host directed therapy by specifically augmenting phagosome-maturation and apoptosis in TB infected macrophage cells.

PubMed

Sharma, Ankur; Vaghasiya, Kalpesh; Gupta, Pushpa; Gupta, Umesh Datta; Verma, Rahul Kumar

2018-01-30

TB-Superbugs have emerged as one of the most challenging global health threat due to the decrease in effectiveness of conventional antibiotics. Meanwhile, Host defense peptides (HDP) have evolved as an alternative to classical therapeutics with lesser susceptibility of resistance. We describe the potential of nano-encapsulated synthetic Magainin-I analog peptide (MIAP) as Host Directed Therapy against TB. Micron-sized inhalable platform "Porous Nanoparticle Aggregates Particles (PNAP)" with nano-scale physiognomies were developed to improve the delivery of MIAP-peptide to the lungs and enhance its stability. This particle engineering enabled more control over aerodynamic characteristics and bioactive release. Antimicrobial and mechanistic studies were carried out against virulent H37Rv TB bacteria. These MIAP-PNAP nano-assemblies demonstrated dose and time dependent antibacterial action against virulent M.tb for at least 96 h, with up to ∼3.03-log CFU reduction in numbers of viable bacteria compared to untreated group. These MIAP-PNAP at concentration of 50 μM and above showed significant antibacterial effects on M.tb after 48-96 h of incubation. Mechanistically, MIAP nano-formulation enhanced host defense mechanism by averting bacteria-induced inhibition of phagosomal-lysosome fusion (Lysostracker) and apoptosis (Annexin-FITC) as shown by confocal microscopy and flow-cytometry. Encapsulated MIAP may serve for adjunctive host-directed TB therapy which may also synergizes the efficacy of standard anti-TB drugs. Copyright © 2017 Elsevier B.V. All rights reserved.

A Cocoa Peptide Protects Caenorhabditis elegans from Oxidative Stress and β-Amyloid Peptide Toxicity

PubMed Central

Martorell, Patricia; Bataller, Esther; Llopis, Silvia; Gonzalez, Núria; Álvarez, Beatriz; Montón, Fernando; Ortiz, Pepa; Ramón, Daniel; Genovés, Salvador

2013-01-01

Background Cocoa and cocoa-based products contain different compounds with beneficial properties for human health. Polyphenols are the most frequently studied, and display antioxidant properties. Moreover, protein content is a very interesting source of antioxidant bioactive peptides, which can be used therapeutically for the prevention of age-related diseases. Methodology/Principal Findings A bioactive peptide, 13L (DNYDNSAGKWWVT), was obtained from a hydrolyzed cocoa by-product by chromatography. The in vitro inhibition of prolyl endopeptidase (PEP) was used as screening method to select the suitable fraction for peptide identification. Functional analysis of 13L peptide was achieved using the transgenic Caenorhabditis elegans strain CL4176 expressing the human Aβ1–42 peptide as a pre-clinical in vivo model for Alzheimer's disease. Among the peptides isolated, peptide 13L (1 µg/mL) showed the highest antioxidant activity (P≤0.001) in the wild-type strain (N2). Furthermore, 13L produced a significant delay in body paralysis in strain CL4176, especially in the 24–47 h period after Aβ1–42 peptide induction (P≤0.0001). This observation is in accordance with the reduction of Aβ deposits in CL4176 by western blot. Finally, transcriptomic analysis in wild-type nematodes treated with 13L revealed modulation of the proteosomal and synaptic functions as the main metabolic targets of the peptide. Conclusions/Significance These findings suggest that the cocoa 13L peptide has antioxidant activity and may reduce Aβ deposition in a C. elegans model of Alzheimer's disease; and therefore has a putative therapeutic potential for prevention of age-related diseases. Further studies in murine models and humans will be essential to analyze the effectiveness of the 13L peptide in higher animals. PMID:23675471

Peptide- and saccharide-conjugated dendrimers for targeted drug delivery: a concise review

PubMed Central

Liu, Jie; Gray, Warren D.; Davis, Michael E.; Luo, Ying

2012-01-01

Dendrimers comprise a category of branched materials with diverse functions that can be constructed with defined architectural and chemical structures. When decorated with bioactive ligands made of peptides and saccharides through peripheral chemical groups, dendrimer conjugates are turned into nanomaterials possessing attractive binding properties with the cognate receptors. At the cellular level, bioactive dendrimer conjugates can interact with cells with avidity and selectivity, and this function has particularly stimulated interests in investigating the targeting potential of dendrimer materials for the design of drug delivery systems. In addition, bioactive dendrimer conjugates have so far been studied for their versatile capabilities to enhance stability, solubility and absorption of various types of therapeutics. This review presents a brief discussion on three aspects of the recent studies to use peptide- and saccharide-conjugated dendrimers for drug delivery: (i) synthesis methods, (ii) cell- and tissue-targeting properties and (iii) applications of conjugated dendrimers in drug delivery nanodevices. With more studies to elucidate the structure–function relationship of ligand–dendrimer conjugates in transporting drugs, the conjugated dendrimers hold promise to facilitate targeted delivery and improve drug efficacy for discovery and development of modern pharmaceutics. PMID:23741608

Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity.

PubMed

Haskell-Luevano, C; Sawyer, T K; Hendrata, S; North, C; Panahinia, L; Stum, M; Staples, D J; Castrucci, A M; Hadley, M F; Hruby, V J

1996-01-01

Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity: PEPTIDES 17(6) 995-1002, 1996.-Systematic analysis of fragment derivatives of the superpotent alpha-MSH analogue. Ac-Ser.Tyr-Ser-Nle4-Glu- His-DPhe7-Arg-Trp-Gly-Lys-Pro-Val-NH2(NDP-MSH), led to the discovery of tripeptide agonists possessing prolonged bioactivity in the frog skin assay. Of particular significance to this discovery was Ac-DPhe-Arg-DTrp-NH2, which was the most potent tripeptide in this series exhibiting sustained melanotropic activity. Different pharmacophore models appear to exist that are dependent on the substructure and stereochemistry of the MSH(6-9) "active site." The tripeptides Ac-DPhe-Arg-Trp-NH2, Ac-DPhe-Arg-DTrp-NH2, and Ac-DPhe-DArg-Trp-NH2 stereo-chemical combinations require only Phe7-Xaa8-Trp9, whereas Ac-DPhe-DArg-DTrp-NH2, Ac-Phe-Arg-DTrp-NH2, and Ac-Phe-Arg-Trp-NH2 additionally require His4 for minimal biological activity. Ac-DPhe-Arg-DTrp-NH2 represents a novel prototype lead for the development of MSH-based peptidomimetic agonists.

Discovering ligands for a microRNA precursor with peptoid microarrays

PubMed Central

Chirayil, Sara; Chirayil, Rachel; Luebke, Kevin J.

2009-01-01

We have screened peptoid microarrays to identify specific ligands for the RNA hairpin precursor of miR-21, a microRNA involved in cancer and heart disease. Microarrays were printed by spotting a library of 7680 N-substituted oligoglycines (peptoids) onto glass slides. Two compounds on the array specifically bind RNA having the sequence and predicted secondary structure of the miR-21 precursor hairpin and have specific affinity for the target in solution. Their binding induces a conformational change around the hairpin loop, and the most specific compound recognizes the loop sequence and a bulged uridine in the proximal duplex. Functional groups contributing affinity and specificity were identified, and by varying a critical methylpyridine group, a compound with a dissociation constant of 1.9 μM for the miR-21 precursor hairpin and a 20-fold discrimination against a closely-related hairpin was created. This work describes a systematic approach to discovery of ligands for specific pre-defined novel RNA structures. It demonstrates discovery of new ligands for an RNA for which no specific lead compounds were previously known by screening a microarray of small molecules. PMID:19561197

Molecular Design of Antifouling Polymer Brushes Using Sequence-Specific Peptoids.

PubMed

Lau, King Hang Aaron; Sileika, Tadas S; Park, Sung Hyun; Sousa, Ana Maria Leal; Burch, Patrick; Szleifer, Igal; Messersmith, Phillip B

2015-01-07

Material systems that can be used to flexibly and precisely define the chemical nature and molecular arrangement of a surface would be invaluable for the control of complex biointerfacial interactions. For example, progress in antifouling polymer biointerfaces that prevent non-specific protein adsorption and cell attachment, which can significantly improve the performance of an array of biomedical and industrial applications, is hampered by a lack of chemical models to identify the molecular features conferring their properties. Poly(N-substituted glycine) "peptoids" are peptidomimetic polymers that can be conveniently synthesized with specific monomer sequences and chain lengths, and are presented as a versatile platform for investigating the molecular design of antifouling polymer brushes. Zwitterionic antifouling polymer brushes have captured significant recent attention, and a targeted library of zwitterionic peptoid brushes with a different charge densities, hydration, separations between charged groups, chain lengths, and grafted chain densities, is quantitatively evaluated for their antifouling properties through a range of protein adsorption and cell attachment assays. Specific zwitterionic brush designs were found to give rise to distinct but subtle differences in properties. The results also point to the dominant roles of the grafted chain density and chain length in determining the performance of antifouling polymer brushes.

Antioxidant activity and bioactive compound contents before and after in vitro digestion of new tomato hybrids.

PubMed

Tommonaro, Giuseppina; Speranza, Giovanna; De Prisco, Rocco; Iodice, Carmine; Crudele, Egle; Abbamondi, Gennaro Roberto; Nicolaus, Barbara

2017-12-01

The antioxidant properties and bioactive compound contents of fresh new tomato hybrids before and after in vitro digestion were investigated. To this aim, the antioxidant activities of lipophilic, hydrophilic and polyphenolic extracts of tomato hybrids were determined by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)), DMPD (N,N-dimethyl-p-phenylenediamine dihydrochloride) and DPPH (2,2-diphenyl-1-picrylhydrazyl) methods respectively, while the bioactive compound contents were estimated via Folin-Ciocalteu (polyphenols), pH differential (anthocyanins) and high-performance liquid chromatography (lycopene and β-carotene) methods. After the digestion process, a marked loss (ranging from 37 to 77%) of antioxidant capacity linked to the hydrophilic fraction was observed. In contrast, the lipophilic and methanolic fractions showed an increase in antioxidant activity (ranging from 9 to 40%) after gastric digestion, and a rapid decrease was observed after total digestion. Moreover, the presence of anthocyanins and carotenoids after simulated digestion was a notable result. The bioavailability of bioactive metabolites from nutraceutical food and their healthful properties in humans are strictly dependent on the digestion process. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Theoretical and experimental studies on alpha/epsilon-hybrid peptides: design of a 14/12-helix from peptides with alternating (S)-C-linked carbo-epsilon-amino acid [(S)-epsilon-Caa((x))] and L-ala.

PubMed

Sharma, Gangavaram V M; Babu, Bommagani Shoban; Chatterjee, Deepak; Ramakrishna, Kallaganti V S; Kunwar, Ajit C; Schramm, Peter; Hofmann, Hans-Jörg

2009-09-04

An (S)-C-linked carbo-epsilon-amino acid [(S)-epsilon-Caa((x))] was prepared from the known (S)-delta-Caa. This monomer was utilized together with l-Ala to give novel alpha/epsilon-hybrid peptides in 1:1 alternation. Conformational analysis on penta- and hexapeptides by NMR (in CDCl(3)), CD, and MD studies led to the identification of robust 14/12-mixed helices. This is in agreement with the data from a theoretical conformational analysis on the basis of ab initio MO theory providing a complete overview on all formally possible hydrogen-bonded helix patterns of alpha/epsilon-hybrid peptides with 1:1 backbone alternation. The "new motif" of a mixed 14/12-helix was predicted as most stable in vacuum. Obviously, the formation of ordered secondary structures is also possible in peptide foldamers with amino acid constituents of considerable backbone lengths. Thus, alpha/epsilon-hybrid peptides expand the domain of foldamers and allow the introduction of desired functionalities via the alpha-amino acid constituents.

Fluorescence Detection of KRAS2 mRNA Hybridization in Lung Cancer Cells with PNA-Peptides Containing an Internal Thiazole Orange

PubMed Central

2015-01-01

We previously developed reporter-peptide nucleic acid (PNA)-peptides for sequence-specific radioimaging and fluorescence imaging of particular mRNAs in cells and tumors. However, a direct test for PNA-peptide hybridization with RNA in the cytoplasm would be desirable. Thiazole orange (TO) dye at the 5′ end of a hybridization agent shows a strong increase in fluorescence quantum yield when stacked upon a 5′ terminal base pair, in solution and in cells. We hypothesized that hybridization agents with an internal TO could distinguish a single base mutation in RNA. Thus, we designed KRAS2 PNA-IGF1 tetrapeptide agents with an internal TO adjacent to the middle base of the 12th codon, a frequent site of cancer-initiating mutations. Our molecular dynamics calculations predicted a disordered bulge with weaker hybridization resulting from a single RNA mismatch. We observed that single-stranded PNA-IGF1 tetrapeptide agents with an internal TO showed low fluorescence, but fluorescence escalated 5–6-fold upon hybridization with KRAS2 RNA. Circular dichroism melting curves showed ∼10 °C higher Tm for fully complementary vs single base mismatch TO-PNA-peptide agent duplexes with KRAS2 RNA. Fluorescence measurements of treated human lung cancer cells similarly showed elevated cytoplasmic fluorescence intensity with fully complementary vs single base mismatch agents. Sequence-specific elevation of internal TO fluorescence is consistent with our hypothesis of detecting cytoplasmic PNA-peptide:RNA hybridization if a mutant agent encounters the corresponding mutant mRNA. PMID:25180641

Peptide-micelle hybrids containing fasudil for targeted delivery to the pulmonary arteries and arterioles to treat pulmonary arterial hypertension.

PubMed

Gupta, Nilesh; Ibrahim, Hany M; Ahsan, Fakhrul

2014-11-01

This study investigates the respirability and efficacy of peptide-micelle hybrid nanoparticles as carriers for inhalational therapy of pulmonary arterial hypertension (PAH). CARSKNKDC (CAR), a cell-penetrating and lung-homing peptide, conjugated polyethylene glycol-distearoyl-phosphoethanolamine micelles containing fasudil, an investigational anti-PAH drug, were prepared by solvent evaporation method and characterized for various physicochemical properties. The pharmacokinetics and pharmacological efficacy of hybrid particles containing fasudil were evaluated in healthy rats and monocrotaline-induced PAH rats. CAR micelles containing fasudil had an entrapment efficiency of approximately 58%, showed controlled release of the drug, and were monodispersed with an average size of approximately 14 nm. Nuclear magnetic resonance scan confirmed the drug's presence in the core of peptide-micelle hybrid particles. Compared with plain micelles, CAR peptide increased the cellular uptake by approximately 1.7-fold and extended the drug half-life by approximately fivefold. The formulations were more prone to accumulate in the pulmonary vasculature than in the peripheral blood, which is evident from the ratio of the extent of reduction of pulmonary and systemic arterial pressures. On the whole, this study demonstrates that peptide-polymer hybrid micelles can serve as inhalational carriers for PAH therapy. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Peptide hormones and lipopeptides: from self‐assembly to therapeutic applications

PubMed Central

Hutchinson, J. A.; Burholt, S.

2017-01-01

This review describes the properties and activities of lipopeptides and peptide hormones and how the lipidation of peptide hormones could potentially produce therapeutic agents combating some of the most prevalent diseases and conditions. The self‐assembly of these types of molecules is outlined, and how this can impact on bioactivity. Peptide hormones specific to the uptake of food and produced in the gastrointestinal tract are discussed in detail. The advantages of lipidated peptide hormones over natural peptide hormones are summarised, in terms of stability and renal clearance, with potential application as therapeutic agents. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. PMID:28127868

In vitro CLE peptide bioactivity assay on plant roots

USDA-ARS?s Scientific Manuscript database

Plant CLAVATA3/ESR (CLE)-related proteins play diverse roles in plant growth and development including regulating the development of root meristem. Mature CLE peptides are typically 12-13 amino acids (aa) in length that are derived from the conserved C-termini of their precursor proteins. Genes enco...

A novel bradykinin potentiating peptide isolated from Bothrops jararacussu venom using catallytically inactive oligopeptidase EP24.15.

PubMed

Rioli, Vanessa; Prezoto, Benedito C; Konno, Katsuhiro; Melo, Robson L; Klitzke, Clécio F; Ferro, Emer S; Ferreira-Lopes, Mônica; Camargo, Antonio C M; Portaro, Fernanda C V

2008-05-01

Characterization of the peptide content of venoms has a number of potential benefits for basic research, clinical diagnosis, development of new therapeutic agents, and production of antiserum. Here, we use a substrate-capture assay that employs a catalytically inactive mutant of thimet oligopeptidase (EC 3.4.24.15; EP24.15) to identify novel bioactive peptides in Bothrops jararacussu venom. Of the peptides captured with inactive EP24.15 and identified by mass spectrometry, three were previously identified bradykinin-potentiating peptides (BPP),

Myticalins: A Novel Multigenic Family of Linear, Cationic Antimicrobial Peptides from Marine Mussels (Mytilus spp.).

PubMed

Leoni, Gabriele; De Poli, Andrea; Mardirossian, Mario; Gambato, Stefano; Florian, Fiorella; Venier, Paola; Wilson, Daniel N; Tossi, Alessandro; Pallavicini, Alberto; Gerdol, Marco

2017-08-22

The application of high-throughput sequencing technologies to non-model organisms has brought new opportunities for the identification of bioactive peptides from genomes and transcriptomes. From this point of view, marine invertebrates represent a potentially rich, yet largely unexplored resource for de novo discovery due to their adaptation to diverse challenging habitats. Bioinformatics analyses of available genomic and transcriptomic data allowed us to identify myticalins, a novel family of antimicrobial peptides (AMPs) from the mussel Mytilus galloprovincialis , and a similar family of AMPs from Modiolus spp., named modiocalins. Their coding sequence encompasses two conserved N-terminal (signal peptide) and C-terminal (propeptide) regions and a hypervariable central cationic region corresponding to the mature peptide. Myticalins are taxonomically restricted to Mytiloida and they can be classified into four subfamilies. These AMPs are subject to considerable interindividual sequence variability and possibly to presence/absence variation. Functional assays performed on selected members of this family indicate a remarkable tissue-specific expression (in gills) and broad spectrum of activity against both Gram-positive and Gram-negative bacteria. Overall, we present the first linear AMPs ever described in marine mussels and confirm the great potential of bioinformatics tools for the de novo discovery of bioactive peptides in non-model organisms.

A High-Protein Soybean Cultivar Contains Lower Isoflavones and Saponins but Higher Minerals and Bioactive Peptides than a Low-Protein Cultivar

USDA-ARS?s Scientific Manuscript database

Consumption of soybean products has increased considerably in the last few years, possibly due to the functional properties and the presence of bioactive compounds which bring health benefits to consumers. The process of germination has been shown to increase the concentration of a number of these ...

Cationic Shell-crosslinked Knedel-like (cSCK) Nanoparticles for Highly Efficient PNA Delivery

PubMed Central

Fang, Huafeng; Zhang, Ke; Shen, Gang; Wooley, Karen L.; Taylor, John-Stephen A.

2009-01-01

Peptide nucleic acids have a number of features that make them an ideal platform for the development of in vitro biological probes and tools. Unfortunately, their inability to pass through membranes has limited their in vivo application as diagnostic and therapeutic agents. Herein, we describe the development of cationic shell-crosslinked knedel-like (cSCK) nanoparticles as highly efficient vehicles for the delivery of PNAs into cells, either through electrostatic complexation with a PNA•ODN hybrid, or through a bioreductively cleavable disulfide linkage to a PNA. These delivery systems are better than the standard lipofectamine/ODN-mediated method and much better than the Arg9-mediated method for PNA delivery in HeLa cells, showing lower toxicity and higher bioactivity. The cSCKs were also found to facilitate both endocytosis and endosomal release of the PNAs, while themselves remaining trapped in the endosomes. PMID:19231840

Biosynthesis of antimycins with a reconstituted 3-formamidosalicylate pharmacophore in Escherichia coli.

PubMed

Liu, Joyce; Zhu, Xuejun; Seipke, Ryan F; Zhang, Wenjun

2015-05-15

Antimycins are a family of natural products generated from a hybrid nonribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) assembly line. Although they possess an array of useful biological activities, their structural complexity makes chemical synthesis challenging, and their biosynthesis has thus far been dependent on slow-growing source organisms. Here, we reconstituted the biosynthesis of antimycins in Escherichia coli, a versatile host that is robust and easy to manipulate genetically. Along with Streptomyces genetic studies, the heterologous expression of different combinations of ant genes enabled us to systematically confirm the functions of the modification enzymes, AntHIJKL and AntO, in the biosynthesis of the 3-formamidosalicylate pharmacophore of antimycins. Our E. coli-based antimycin production system can not only be used to engineer the increased production of these bioactive compounds, but it also paves the way for the facile generation of novel and diverse antimycin analogues through combinatorial biosynthesis.

Biological nano-functionalization of titanium-based biomaterial surfaces: a flexible toolbox

PubMed Central

Beutner, René; Michael, Jan; Schwenzer, Bernd; Scharnweber, Dieter

2010-01-01

Surface functionalization with bioactive molecules (BAMs) on a nanometre scale is a main field in current biomaterial research. The immobilization of a vast number of substances and molecules, ranging from inorganic calcium phosphate phases up to peptides and proteins, has been investigated throughout recent decades. However, in vitro and in vivo results are heterogeneous. This may be at least partially attributed to the limits of the applied immobilization methods. Therefore, this paper highlights, in the first part, advantages and limits of the currently applied methods for the biological nano-functionalization of titanium-based biomaterial surfaces. The second part describes a new immobilization system recently developed in our groups. It uses the nanomechanical fixation of at least partially single-stranded nucleic acids (NAs) into an anodic titanium oxide layer as an immobilization principle and their hybridization ability for the functionalization of the surface with BAMs conjugated to the respective complementary NA strands. PMID:19889692

High-throughput microfluidic mixing and multiparametric cell sorting for bioactive compound screening.

PubMed

Young, Susan M; Curry, Mark S; Ransom, John T; Ballesteros, Juan A; Prossnitz, Eric R; Sklar, Larry A; Edwards, Bruce S

2004-03-01

HyperCyt, an automated sample handling system for flow cytometry that uses air bubbles to separate samples sequentially introduced from multiwell plates by an autosampler. In a previously documented HyperCyt configuration, air bubble separated compounds in one sample line and a continuous stream of cells in another are mixed in-line for serial flow cytometric cell response analysis. To expand capabilities for high-throughput bioactive compound screening, the authors investigated using this system configuration in combination with automated cell sorting. Peptide ligands were sampled from a 96-well plate, mixed in-line with fluo-4-loaded, formyl peptide receptor-transfected U937 cells, and screened at a rate of 3 peptide reactions per minute with approximately 10,000 cells analyzed per reaction. Cell Ca(2+) responses were detected to as little as 10(-11) M peptide with no detectable carryover between samples at up to 10(-7) M peptide. After expansion in culture, cells sort-purified from the 10% highest responders exhibited enhanced sensitivity and more sustained responses to peptide. Thus, a highly responsive cell subset was isolated under high-throughput mixing and sorting conditions in which response detection capability spanned a 1000-fold range of peptide concentration. With single-cell readout systems for protein expression libraries, this technology offers the promise of screening millions of discrete compound interactions per day.

Diet Bioactive Compounds: Implications for Oxidative Stress and Inflammation in the Vascular System.

PubMed

Gabriele, Morena; Pucci, Laura

2017-11-16

Increasing evidence has demonstrated that dietary products and their active components are independently or jointly responsible for the apparent reduction of the cardiovascular diseases (CVDs) risk. Nowadays, there is a growing attention in the use of nutraceuticals as a new approach for the prevention and management of many diseases, as well as for controlling rising of chronic illnesses with minimal side effects. Food-derived peptides, as well as peptide-rich protein hydrolysates, represent new and valuable tools for the prevention of metabolic and cardiovascular diseases, acting as modulators of oxidative stress, inflammation, and overactivity of the renin-angiotensin system (RAS). This review summarizes the recently published data on antioxidant, anti-inflammatory, and vascular protective properties of nutraceuticals, notably on the effects of food-derived bioactive peptides and protein hydrolysates, paying particular attention to those derived from fermented foods. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Entomopathogenic bacteria use multiple mechanisms for bioactive peptide library design

NASA Astrophysics Data System (ADS)

Cai, Xiaofeng; Nowak, Sarah; Wesche, Frank; Bischoff, Iris; Kaiser, Marcel; Fürst, Robert; Bode, Helge. B.

2017-04-01

The production of natural product compound libraries has been observed in nature for different organisms such as bacteria, fungi and plants; however, little is known about the mechanisms generating such chemically diverse libraries. Here we report mechanisms leading to the biosynthesis of the chemically diverse rhabdopeptide/xenortide peptides (RXPs). They are exclusively present in entomopathogenic bacteria of the genera Photorhabdus and Xenorhabdus that live in symbiosis with nematodes delivering them to insect prey, which is killed and utilized for nutrition by both nematodes and bacteria. Chemical diversity of the biologically active RXPs results from a combination of iterative and flexible use of monomodular nonribosomal peptide synthetases including substrate promiscuity, enzyme cross-talk and enzyme stoichiometry as shown by in vivo and in vitro experiments. Together, this highlights several of nature's methods for diversification, or evolution, of natural products and sheds light on the biosynthesis of the bioactive RXPs.

Bioactive Peptides Isolated from Casein Phosphopeptides Enhance Calcium and Magnesium Uptake in Caco-2 Cell Monolayers.

PubMed

Cao, Yong; Miao, Jianyin; Liu, Guo; Luo, Zhen; Xia, Zumeng; Liu, Fei; Yao, Mingfei; Cao, Xiaoqiong; Sun, Shengwei; Lin, Yanyin; Lan, Yaqi; Xiao, Hang

2017-03-22

The ability of casein phosphopeptides (CPPs) to bind and transport minerals has been previously studied. However, the single bioactive peptides responsible for the effects of CPPs have not been identified. This study was to purify calcium-binding peptides from CPPs and to determine their effects on calcium and magnesium uptake by Caco-2 cell monolayers. Five monomer peptides designated P1 to P5 were isolated and the amino acid sequences were determined using LC-MS/MS. Compared with the CPP-free control, all five monomeric peptides exhibited significant enhancing effects on the uptake of calcium and magnesium (P < 0.05). Interestingly, when calcium and magnesium were presented simultaneously with P5, magnesium was taken up with priority over calcium in the Caco-2 cell monolayers. For example, at 180 min, the amount of transferred magnesium and calcium was 78.4 ± 0.95 μg/well and 2.56 ± 0.64 μg/well, respectively, showing a more than 30-fold difference in the amount of transport caused by P5. These results provide novel insight into the mineral transport activity of phosphopeptides obtained from casein.

Bioactivity of food peptides: biological response of rats to bovine milk whey peptides following acute exercise

PubMed Central

Moura, Carolina Soares; Lollo, Pablo Christiano Barboza; Morato, Priscila Neder; Risso, Eder Muller; Amaya-Farfan, Jaime

2017-01-01

ABSTRACT Background: Several physiologically beneficial effects of consuming a whey protein hydrolysate (WPH) have been attributed to the greater availability of bioactive peptides. Aims: The aim was to investigate the effect of four branched-chain amino acid- (BCAA-)containing dipeptides, present in WPH, on immune modulation, stimulation of HSP expression, muscle protein synthesis, glycogen content, satiety signals and the impact of these peptides on the plasma free amino acid profiles. Methods: The animals were divided in groups: control (rest, without gavage), vehicle (water), L-isoleucyl-L-leucine (lle-Leu), L-leucyl-L-isoleucine (Leu-lle), L-valyl-Lleucine (Val-Leu), L-leucyl-L-valine (Leu-Val) and WPH. All animals were submitted to acute exercise, except for control. Results: lle-Leu stimulated immune response, hepatic and muscle glycogen and HSP60 expression, whereas Leu-Val enhanced HSP90 expression. All dipeptides reduced glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, no changes were observed on leptin. All peptides inhibited NF-kB expression. The plasma amino acid time-course showed peptide-specific and isomer-specific metabolic features, including increases of the BCAAs. Conclusion: The data indicate that lle-Leu was effective to attenuate immune-suppression exercise-induced, promoted glycogen content and stimulated anti-stress effect (HSP). Furthermore, Leu-Val increased HSP90, p-4EBP1, p-mTOR and p-AMPK expression. The data suggest the involvement of these peptides in various beneficial functions of WPH consumption. PMID:28326005

Tailoring peptide amphiphiles and their assemblies for biomedical applications

NASA Astrophysics Data System (ADS)

Lin, Brian

Peptide amphiphiles (PAs) are molecules composed of a peptide conjugated to a hydrophobic moiety, commonly a fatty acid. They closely resemble the structure of naturally occurring lipopeptides, produced by microbes as signaling and antimicrobial agents. The amphiphilic nature of PAs in concert with the large number of discovered functional peptides inspired scientists to exploit this molecular architecture for producing synthetic self-assembled bioactive materials. PA assemblies are sought after for a wide breadth of applications including disease therapy, regenerative medicine, and catalysis. However, with PAs, the peptide chemistry is a double-edged sword. The peptide component contributes significantly to both the activity and self-assembly. The physiochemical properties of different PAs lead to unique aggregation stability and morphological characteristics which are unpredictable, a priori. Therefore it is challenging to design bioactive PAs and control their self-assembly, simultaneously. This limitation slows the development of PAs for medical use. In this dissertation, methods to control the self-assembly of PAs and the effects of acylating a functional peptide will be discussed. In one part, efforts to direct the self-assembly of PAs into small spherical aggregates, a morphology infrequently observed, will be described. In another section, a strategy to control the stability of PA assemblies will be discussed. In the last section, a pH-responsive membrane perturbing peptide was modified with fatty acid tails and the properties of the resulting PAs will be presented. This dissertation provides some fundamental insight for the use and design of PA self-assemblies.

Structure, Content, and Bioactivity of Food-Derived Peptides in the Body.

PubMed

Sato, Kenji

2018-03-28

Orally administered peptides are assumed to be degraded into amino acids in the body. However, our recent studies revealed some food-derived prolyl and pyroglutamyl peptides with 2-3 amino acid residues in the blood of humans and animals, while most of the peptides in the endoproteinase digest of food protein are degraded by exopeptidase. Some food-derived dipeptides in the body display in vitro and in vivo biological activities. These facts indicate that the biological activities of food-derived peptides in the body rather than those in food are crucial to understanding the mechanism of the beneficial effects of orally administered peptides.

Biological response on a titanium implant-grade surface functionalized with modular peptides☆

PubMed Central

Yazici, H.; Fong, H.; Wilson, B.; Oren, E.E.; Amos, F.A.; Zhang, H.; Evans, J.S.; Snead, M.L.; Sarikaya, M.; Tamerler, C.

2015-01-01

Titanium (Ti) and its alloys are among the most successful implantable materials for dental and orthopedic applications. The combination of excellent mechanical and corrosion resistance properties makes them highly desirable as endosseous implants that can withstand a demanding biomechanical environment. Yet, the success of the implant depends on its osteointegration, which is modulated by the biological reactions occurring at the interface of the implant. A recent development for improving biological responses on the Ti-implant surface has been the realization that bifunctional peptides can impart material binding specificity not only because of their molecular recognition of the inorganic material surface, but also through their self-assembly and ease of biological conjugation properties. To assess peptide-based functionalization on bioactivity, the present authors generated a set of peptides for implant-grade Ti, using cell surface display methods. Out of 60 unique peptides selected by this method, two of the strongest titanium binding peptides, TiBP1 and TiBP2, were further characterized for molecular structure and adsorption properties. These two peptides demonstrated unique, but similar molecular conformations different from that of a weak binder peptide, TiBP60. Adsorption measurements on a Ti surface revealed that their disassociation constants were 15-fold less than TiBP60. Their flexible and modular use in biological surface functionalization were demonstrated by conjugating them with an integrin recognizing peptide motif, RGDS. The functionalization of the Ti surface by the selected peptides significantly enhanced the bioactivity of osteoblast and fibroblast cells on implant-grade materials. PMID:23159566

Recent Research in Antihypertensive Activity of Food Protein-derived Hydrolyzates and Peptides.

PubMed

Saleh, Ahmed S M; Zhang, Qing; Shen, Qun

2016-01-01

Year to year obesity prevalence, reduced physical activities, bad habits/or stressful lifestyle, and other environmental and physiological impacts lead to increase in diseases such as coronary heart disease, stroke, cancer, diabetes, and hypertension worldwide. Hypertension is considered as one of the most common serious chronic diseases; however, discovery of medications with high efficacy and without side effects for treatment of patients remains a challenge for scientists. Recent trends in functional foods have evidenced that food bioactive proteins play a major role in the concepts of illness and curing; therefore, nutritionists, biomedical scientists, and food scientists are working together to develop improved systems for the discovery of peptides with increased potency and therapeutic benefits. This review presents a recent research carried out to date for the purpose of isolation and identification of bioactive hydrolyzates and peptides with angiotensin I converting enzyme inhibitory activity and antihypertensive effect from animal, marine, microbial, and plant food proteins. Effects of food processing and hydrolyzation conditions as well as some other impacts on formation, activity, and stability of these hydrolyzates and peptides are also presented.

ACE Inhibitory and Antioxidant Activities of Collagen Hydrolysates from the Ribbon Jellyfish (Chrysaora sp.).

PubMed

Barzideh, Zoha; Latiff, Aishah Abd; Gan, Chee-Yuen; Abedin, Md Zainul; Alias, Abd Karim

2014-12-01

Collagen isolated from the ribbon jellyfish ( Chrysaora sp.) was hydrolysed using three different proteases ( i.e. trypsin, alcalase and Protamex) to obtain bioactive peptides. Angiotensin-I-converting enzyme (ACE) inhibitory activity and antioxidant activities ( i.e. ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) of the peptides were measured and compared, and the effect of the duration of hydrolysis on the bioactivity (ACE inhibitory and antioxidant activities) of peptides was also evaluated. FRAP activity was the highest in Protamex-induced (25-27 mM) and trypsin-induced hydrolysates (24-26 mM) at 7 and 9 h, respectively. Conversely, hydrolysates produced by trypsin for 1 and 3 h showed the highest DPPH radical scavenging activities (94 and 92%, respectively). Trypsin-induced hydrolysates (at 3 h) also showed the highest ACE inhibitory activity (89%). The peptide sequences with the highest activities were identified using tandem mass spectrometry, and the results show that the hydrolysates had a high content of hydrophobic amino acids as well as unique amino acid sequences, which likely contribute to their biological activities.

Lipid-lipid and lipid-drug interactions in biological membranes

NASA Astrophysics Data System (ADS)

Martynowycz, Michael W.

Interactions between lipids and drug molecules in biological membranes help govern proper biological function in organisms. The mechanisms responsible for hydrophobic drug permeation remain elusive. Many small molecule drugs are hydrophobic. These drugs inhibit proteins in the cellular interior. The rise of antibiotic resistance in bacteria is thought to be caused by mutations in protein structure, changing drug kinetics to favor growth. However, small molecule drugs have been shown to have different mechanisms depending in the structure of the lipid membrane of the target cell. Biological membranes are investigated using Langmuir monolayers at the air-liquid interface. These offer the highest level of control in the mimetic system and allow them to be investigated using complementary techniques. Langmuir isotherms and insertion assays are used to determine the area occupied by each lipid in the membrane and the change in area caused by the introduction of a drug molecule, respectively. Specular X-ray reflectivity is used to determine the electron density of the monolayer, and grazing incidence X-ray diffraction is used to determine the in-plane order of the monolayer. These methods determine the affinity of the drug and the mechanism of action. Studies are presented on hydrophobic drugs with mammalian membrane mimics using warfarin along with modified analogues, called superwarfarins. Data shows that toxicity of these modified drugs are modulated by the membrane cholesterol content in cells; explaining several previously unexplained effects of the drugs. Membrane mimics of bacteria are investigated along with their interactions with a hydrophobic antibiotic, novobiocin. Data suggests that permeation of the drug is mediated by modifications to the membrane lipids, and completely ceases translocation under certain circumstances. Circumventing deficiencies in small, hydrophobic drugs is approached by using biologically mimetic oligomers. Peptoids, mimetic of host defense peptides from the innate immune system, are active against bacteria, and avoid developed antibiotic resistance. Optimization of peptoids by modulation of hydrophobicity and structural rigidity are explored.

Therapeutic Properties of Bioactive Compounds from Different Honeybee Products

PubMed Central

Cornara, Laura; Biagi, Marco; Xiao, Jianbo; Burlando, Bruno

2017-01-01

Honeybees produce honey, royal jelly, propolis, bee venom, bee pollen, and beeswax, which potentially benefit to humans due to the bioactives in them. Clinical standardization of these products is hindered by chemical variability depending on honeybee and botanical sources, but different molecules have been isolated and pharmacologically characterized. Major honey bioactives include phenolics, methylglyoxal, royal jelly proteins (MRJPs), and oligosaccharides. In royal jelly there are antimicrobial jelleins and royalisin peptides, MRJPs, and hydroxy-decenoic acid derivatives, notably 10-hydroxy-2-decenoic acid (10-HDA), with antimicrobial, anti-inflammatory, immunomodulatory, neuromodulatory, metabolic syndrome preventing, and anti-aging activities. Propolis contains caffeic acid phenethyl ester and artepillin C, specific of Brazilian propolis, with antiviral, immunomodulatory, anti-inflammatory and anticancer effects. Bee venom consists of toxic peptides like pain-inducing melittin, SK channel blocking apamin, and allergenic phospholipase A2. Bee pollen is vitaminic, contains antioxidant and anti-inflammatory plant phenolics, as well as antiatherosclerotic, antidiabetic, and hypoglycemic flavonoids, unsaturated fatty acids, and sterols. Beeswax is widely used in cosmetics and makeup. Given the importance of drug discovery from natural sources, this review is aimed at providing an exhaustive screening of the bioactive compounds detected in honeybee products and of their curative or adverse biological effects. PMID:28701955

Urotensin II in Invertebrates: From Structure to Function in Aplysia californica

PubMed Central

Romanova, Elena V.; Sasaki, Kosei; Alexeeva, Vera; Vilim, Ferdinand S.; Jing, Jian; Richmond, Timothy A.; Weiss, Klaudiusz R.; Sweedler, Jonathan V.

2012-01-01

Neuropeptides are ancient signaling molecules that are involved in many aspects of organism homeostasis and function. Urotensin II (UII), a peptide with a range of hormonal functions, previously has been reported exclusively in vertebrates. Here, we provide the first direct evidence that UII-like peptides are also present in an invertebrate, specifically, the marine mollusk Aplysia californica. The presence of UII in the central nervous system (CNS) of Aplysia implies a more ancient gene lineage than vertebrates. Using representational difference analysis, we identified an mRNA of a protein precursor that encodes a predicted neuropeptide, we named Aplysia urotensin II (apUII), with a sequence and structural similarity to vertebrate UII. With in-situ hybridization and immunohistochemistry, we mapped the expression of apUII mRNA and its prohormone in the CNS and localized apUII-like immunoreactivity to buccal sensory neurons and cerebral A-cluster neurons. Mass spectrometry performed on individual isolated neurons, and tandem mass spectrometry on fractionated peptide extracts, allowed us to define the posttranslational processing of the apUII neuropeptide precursor and confirm the highly conserved cyclic nature of the mature neuropeptide apUII. Electrophysiological analysis of the central effects of a synthetic apUII suggests it plays a role in satiety and/or aversive signaling in feeding behaviors. Finding the homologue of vertebrate UII in the numerically small CNS of an invertebrate animal model is important for gaining insights into the molecular mechanisms and pathways mediating the bioactivity of UII in the higher metazoan. PMID:23144960

Bioassembled layered silicate-metal nanoparticle hybrids.

PubMed

Drummy, Lawrence F; Jones, Sharon E; Pandey, Ras B; Farmer, B L; Vaia, Richard A; Naik, Rajesh R

2010-05-01

Here we report on the bioenabled assembly of layered nanohybrids using peptides identified with regard to their affinity to the nanoparticle surface. A dodecamer peptide termed M1, determined from a phage peptide display library, was found to bind to the surface of a layered aluminosilicate (montmorillonite, MMT). Fusion of a metal binding domain to the M1 peptide or the M1 peptide by itself was able to direct the growth of metal nanoparticles, such as gold and cobalt-platinum, respectively, on the MMT. This method of producing hybrid nanoclay materials will have utility in catalytic, optical, biomedical, and composite materials applications.

Sponge-Derived Kocuria and Micrococcus spp. as Sources of the New Thiazolyl Peptide Antibiotic Kocurin

PubMed Central

Palomo, Sara; González, Ignacio; de la Cruz, Mercedes; Martín, Jesús; Tormo, José Rubén; Anderson, Matthew; Hill, Russell T.; Vicente, Francisca; Reyes, Fernando; Genilloud, Olga

2013-01-01

Forty four marine actinomycetes of the family Microccocaceae isolated from sponges collected primarily in Florida Keys (USA) were selected from our strain collection to be studied as new sources for the production of bioactive natural products. A 16S rRNA gene based phylogenetic analysis showed that the strains are members of the genera Kocuria and Micrococcus. To assess their biosynthetic potential, the strains were PCR screened for the presence of secondary metabolite genes encoding nonribosomal synthetase (NRPS) and polyketide synthases (PKS). A small extract collection of 528 crude extracts generated from nutritional microfermentation arrays was tested for the production of bioactive secondary metabolites against clinically relevant strains (Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and Candida albicans). Three independent isolates were shown to produce a new anti-MRSA bioactive compound that was identified as kocurin, a new member of the thiazolyl peptide family of antibiotics emphasizing the role of this family as a prolific resource for novel drugs. PMID:23538871

Sponge-derived Kocuria and Micrococcus spp. as sources of the new thiazolyl peptide antibiotic kocurin.

PubMed

Palomo, Sara; González, Ignacio; de la Cruz, Mercedes; Martín, Jesús; Tormo, José Rubén; Anderson, Matthew; Hill, Russell T; Vicente, Francisca; Reyes, Fernando; Genilloud, Olga

2013-03-28

Forty four marine actinomycetes of the family Microccocaceae isolated from sponges collected primarily in Florida Keys (USA) were selected from our strain collection to be studied as new sources for the production of bioactive natural products. A 16S rRNA gene based phylogenetic analysis showed that the strains are members of the genera Kocuria and Micrococcus. To assess their biosynthetic potential, the strains were PCR screened for the presence of secondary metabolite genes encoding nonribosomal synthetase (NRPS) and polyketide synthases (PKS). A small extract collection of 528 crude extracts generated from nutritional microfermentation arrays was tested for the production of bioactive secondary metabolites against clinically relevant strains (Bacillus subtilis, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii and Candida albicans). Three independent isolates were shown to produce a new anti-MRSA bioactive compound that was identified as kocurin, a new member of the thiazolyl peptide family of antibiotics emphasizing the role of this family as a prolific resource for novel drugs.

TiO2 micro-nano-hybrid surface to alleviate biological aging of UV-photofunctionalized titanium

PubMed Central

Iwasa, Fuminori; Tsukimura, Naoki; Sugita, Yoshihiko; Kanuru, Rajita Kodali; Kubo, Katsutoshi; Hasnain, Hafiz; Att, Wael; Ogawa, Takahiro

2011-01-01

Bioactivity and osteoconductivity of titanium degrade over time after surface processing. This time-dependent degradation is substantial and defined as the biological aging of titanium. UV treatment has shown to reactivate the aged surfaces, a process known as photofunctionalization. This study determined whether there is a difference in the behavior of biological aging for titanium with micro-nano-hybrid topography and titanium with microtopography alone, following functionalization. Titanium disks were acid etched to create micropits on the surface. Micro-nano-hybrid surfaces were created by depositioning 300-nm diameter TiO2 nodules onto the micropits using a previously established self-assembly protocol. These disks were stored for 8 weeks in the dark to allow sufficient aging, then treated with UV light for 48 hours. Rat bone marrow–derived osteoblasts were cultured on fresh disks (immediately after UV treatment), 3-day-old disks (disks stored for 3 days after UV treatment), and 7-day- old disks. The rates of cell attachment, spread, proliferation, and levels of alkaline phosphatase activity, and calcium deposition were reduced by 30%–50% on micropit surfaces, depending on the age of the titanium. In contrast, 7-day-old hybrid surfaces maintained equivalent levels of bioactivity compared with the fresh surfaces. Both micropit and micro-nano-hybrid surfaces were superhydrophilic immediately after UV treatment. However, after 7 days, the micro-nano- hybrid surfaces became hydrorepellent, while the micropit surfaces remained hydrophilic. The sustained bioactivity levels of the micro-nano-hybrid surfaces were nullified by treating these surfaces with Cl−anions. A thin TiO2 coating on the micropit surface without the formation of nanonodules did not result in the prevention or alleviation of the time-dependent decrease in biological activity. In conclusion, the micro-nano-hybrid titanium surfaces may slow the rate of time-dependent degradation of titanium bioactivity after UV photofunctionalization compared with titanium surfaces with microtopography alone. This antibiological aging effect was largely regulated by its sustained electropositivity uniquely conferred in TiO2 nanonodules, and was independent of the degree of hydrophilicity. These results demonstrate the potential usefulness of these hybrid surfaces to effectively utilize the benefits of UV photofunctionalization and provide a model to explore the mechanisms underlying antibiological aging properties. PMID:21760728

TiO2 micro-nano-hybrid surface to alleviate biological aging of UV-photofunctionalized titanium.

PubMed

Iwasa, Fuminori; Tsukimura, Naoki; Sugita, Yoshihiko; Kanuru, Rajita Kodali; Kubo, Katsutoshi; Hasnain, Hafiz; Att, Wael; Ogawa, Takahiro

2011-01-01

Bioactivity and osteoconductivity of titanium degrade over time after surface processing. This time-dependent degradation is substantial and defined as the biological aging of titanium. UV treatment has shown to reactivate the aged surfaces, a process known as photofunctionalization. This study determined whether there is a difference in the behavior of biological aging for titanium with micro-nano-hybrid topography and titanium with microtopography alone, following functionalization. Titanium disks were acid etched to create micropits on the surface. Micro-nano-hybrid surfaces were created by depositioning 300-nm diameter TiO(2) nodules onto the micropits using a previously established self-assembly protocol. These disks were stored for 8 weeks in the dark to allow sufficient aging, then treated with UV light for 48 hours. Rat bone marrow-derived osteoblasts were cultured on fresh disks (immediately after UV treatment), 3-day-old disks (disks stored for 3 days after UV treatment), and 7-day- old disks. The rates of cell attachment, spread, proliferation, and levels of alkaline phosphatase activity, and calcium deposition were reduced by 30%-50% on micropit surfaces, depending on the age of the titanium. In contrast, 7-day-old hybrid surfaces maintained equivalent levels of bioactivity compared with the fresh surfaces. Both micropit and micro-nano-hybrid surfaces were superhydrophilic immediately after UV treatment. However, after 7 days, the micro-nano- hybrid surfaces became hydrorepellent, while the micropit surfaces remained hydrophilic. The sustained bioactivity levels of the micro-nano-hybrid surfaces were nullified by treating these surfaces with Cl(-)anions. A thin TiO(2) coating on the micropit surface without the formation of nanonodules did not result in the prevention or alleviation of the time-dependent decrease in biological activity. In conclusion, the micro-nano-hybrid titanium surfaces may slow the rate of time-dependent degradation of titanium bioactivity after UV photofunctionalization compared with titanium surfaces with microtopography alone. This antibiological aging effect was largely regulated by its sustained electropositivity uniquely conferred in TiO(2) nanonodules, and was independent of the degree of hydrophilicity. These results demonstrate the potential usefulness of these hybrid surfaces to effectively utilize the benefits of UV photofunctionalization and provide a model to explore the mechanisms underlying antibiological aging properties.

Bioactive Molecules Released in Food by Lactic Acid Bacteria: Encrypted Peptides and Biogenic Amines

PubMed Central

Pessione, Enrica; Cirrincione, Simona

2016-01-01

Lactic acid bacteria (LAB) can produce a huge amount of bioactive compounds. Since their elective habitat is food, especially dairy but also vegetal food, it is frequent to find bioactive molecules in fermented products. Sometimes these compounds can have adverse effects on human health such as biogenic amines (tyramine and histamine), causing allergies, hypertensive crises, and headache. However, some LAB products also display benefits for the consumers. In the present review article, the main nitrogen compounds produced by LAB are considered. Besides biogenic amines derived from the amino acids tyrosine, histidine, phenylalanine, lysine, ornithine, and glutamate by decarboxylation, interesting peptides can be decrypted by the proteolytic activity of LAB. LAB proteolytic system is very efficient in releasing encrypted molecules from several proteins present in different food matrices. Alpha and beta-caseins, albumin and globulin from milk and dairy products, rubisco from spinach, beta-conglycinin from soy and gluten from cereals constitute a good source of important bioactive compounds. These encrypted peptides are able to control nutrition (mineral absorption and oxidative stress protection), metabolism (blood glucose and cholesterol lowering) cardiovascular function (antithrombotic and hypotensive action), infection (microbial inhibition and immunomodulation) and gut-brain axis (opioids and anti-opioids controlling mood and food intake). Very recent results underline the role of food-encrypted peptides in protein folding (chaperone-like molecules) as well as in cell cycle and apoptosis control, suggesting new and positive aspects of fermented food, still unexplored. In this context, the detailed (transcriptomic, proteomic, and metabolomic) characterization of LAB of food interest (as starters, biocontrol agents, nutraceuticals, and probiotics) can supply a solid evidence-based science to support beneficial effects and it is a promising approach as well to obtain functional food. The detailed knowledge of the modulation of human physiology, exploiting the health-promoting properties of fermented food, is an open field of investigation that will constitute the next challenge. PMID:27375596

Predicting hepatotoxicity using ToxCast in vitro bioactivity and ...

EPA Pesticide Factsheets

Background: The U.S. EPA ToxCastTM program is screening thousands of environmental chemicals for bioactivity using hundreds of high-throughput in vitro assays to build predictive models of toxicity. We represented chemicals based on bioactivity and chemical structure descriptors then used supervised machine learning to predict their hepatotoxic effects.Results: A set of 677 chemicals were represented by 711 in vitro bioactivity descriptors (from ToxCast assays), 4,376 chemical structure descriptors (from QikProp, OpenBabel, PADEL, and PubChem), and three hepatotoxicity categories (from animal studies). Hepatotoxicants were defined by rat liver histopathology observed after chronic chemical testing and grouped into hypertrophy (161), injury (101) and proliferative lesions (99). Classifiers were built using six machine learning algorithms: linear discriminant analysis (LDA), Naïve Bayes (NB), support vector classification (SVM), classification and regression trees (CART), k-nearest neighbors (KNN) and an ensemble of classifiers (ENSMB). Classifiers of hepatotoxicity were built using chemical structure, ToxCast bioactivity, and a hybrid representation. Predictive performance was evaluated using 10-fold cross-validation testing and in-loop, filter-based, feature subset selection. Hybrid classifiers had the best balanced accuracy for predicting hypertrophy (0.78±0.08), injury (0.73±0.10) and proliferative lesions (0.72±0.09). Though chemical and bioactivity class

Ribosomal synthesis and folding of peptide-helical aromatic foldamer hybrids

NASA Astrophysics Data System (ADS)

Rogers, Joseph M.; Kwon, Sunbum; Dawson, Simon J.; Mandal, Pradeep K.; Suga, Hiroaki; Huc, Ivan

2018-03-01

Translation, the mRNA-templated synthesis of peptides by the ribosome, can be manipulated to incorporate variants of the 20 cognate amino acids. Such approaches for expanding the range of chemical entities that can be produced by the ribosome may accelerate the discovery of molecules that can perform functions for which poorly folded, short peptidic sequences are ill suited. Here, we show that the ribosome tolerates some artificial helical aromatic oligomers, so-called foldamers. Using a flexible tRNA-acylation ribozyme—flexizyme—foldamers were attached to tRNA, and the resulting acylated tRNAs were delivered to the ribosome to initiate the synthesis of non-cyclic and cyclic foldamer-peptide hybrid molecules. Passing through the ribosome exit tunnel requires the foldamers to unfold. Yet foldamers encode sufficient folding information to influence the peptide structure once translation is completed. We also show that in cyclic hybrids, the foldamer portion can fold into a helix and force the peptide segment to adopt a constrained and stretched conformation.

Molecular dynamics simulations of certain RGD-based peptides from Kistrin provide insight into the higher activity of REI-RGD34 protein at higher temperature.

PubMed

Upadhyay, Sanjay K

2014-05-01

To determine the bioactive conformation required to bind with receptor aIIbb3, the peptide sequence RIPRGDMP from Kistrin was inserted into CDR 1 loop region of REI protein, resulting in REI-RGD34. The activity of REI-RGD34 was observed to increase at higher temperature towards the receptor aIIbb3. It could be justified in either way: the modified complex forces the restricted peptide to adapt bioactive conformation or it unfolds the peptide in a way that opens its binding surface with high affinity for receptor. Here, we model the conformational preference of RGD sequence in RIPRGDMP at 25 and 42 °C using multiple MD simulations. Further, we model the peptide sequence RGD, PRGD and PRGDMP from kistrin to observe the effect of flanking residues on conformational sampling of RGD. The presence of flanking residues around RGD peptide greatly influenced the conformational sampling. A transition from bend to turn conformation was observed for RGD sequence at 42 °C. The turn conformation shows pharmacophoric parameters required to recognize the receptor aIIbb3. Thus, the temperaturedependent activity of RIPRGDMP when inserted into the loop region of REI can be explained by the presence of the turn conformation. This study will help in designing potential antagonist for the receptor aIIbb3.

Short communication: Inhibition of angiotensin 1-converting enzyme by peptides derived from variants of bovine β-casein upon apical exposure to a Caco-2 cell monolayer.

PubMed

Petrat-Melin, Bjørn; Le, Thao T; Møller, Hanne S; Larsen, Lotte B; Young, Jette F

2017-02-01

This study investigated the consequence of genetically contingent amino acid substitutions in bovine β-casein (CN) genetic variants A 1 , A 2 , B, and I on the structure and bioactive potential of peptides following in vitro digestion. The β-CN variants were digested in vitro using pepsin and pancreatin, and a peptide profile was obtained by liquid chromatography tandem mass spectrometry, revealing among others, the β-casomorphin precursor peptides VYPFPGPIHN and VYPFPGPIPN, derived from variant A 1 /B and from A 2 /I, respectively. These 2 peptides were synthesized and assessed for angiotensin 1-converting enzyme (ACE) inhibitory capacity before and after incubation with a monolayer of Caco-2 intestinal cells. The VYPFPGPIHN was a stronger ACE inhibitor than VYPFPGPIPN, with the concentration needed to reach half-maximal inhibition (IC 50 ) of 123 ± 14.2 μM versus 656 ± 7.6 μM. Exposure to a Caco-2 intestinal cell monolayer did not affect ACE inhibition by VYPFPGPIHN, but resulted in an almost 2-fold increase in inhibition by VYPFPGPIPN after incubation. Subsequent tandem mass spectrometric analysis identified the truncated peptide VYPFPGPIP, suggesting hydrolysis by a cell membrane associated peptidase. Thus, genetic variation in bovine β-CN results in the generation of peptides that differ in bioactivity, and are differently affected by intestinal brush border peptidases. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Peptide-incorporated 3D porous alginate scaffolds with enhanced osteogenesis for bone tissue engineering.

PubMed

Luo, Zuyuan; Yang, Yue; Deng, Yi; Sun, Yuhua; Yang, Hongtao; Wei, Shicheng

2016-07-01

Good bioactivity and osteogenesis of three-dimensional porous alginate scaffolds (PAS) are critical for bone tissue engineering. In this work, alginate and bone-forming peptide-1 (BFP-1), derived from bone morphogenetic protein-7 (BMP-7), have been combined together (without carbodiimide chemistry treatment) to develop peptide-incorporated PAS (p-PAS) for promoting bone repairing ability. The mechanical properties and SEM images show no difference between pure PAS and p-PAS. The release kinetics of the labeled peptide with 6-carboxy tetramethyl rhodamine from the PAS matrix suggests that the peptide is released in a relatively sustained manner. In the cell experiment, p-PAS show higher cell adhesion, spreading, proliferation and alkaline phosphatase (ALP) activity than the pristine PAS group, indicating that the BFP-1 released from p-PAS could significantly promote the aggregation and differentiation of osteoblasts, especially at 10μg/mL of trapped peptide concentration (p-PAS-10). Furthermore, p-PAS-10 was implanted into Beagle calvarial defects and bone regeneration was analyzed after 4 weeks. New bone formation was assessed by calcein and Masson's trichrome staining. The data reveal that p-PAS group exhibits significantly enhanced oseto-regenerative capability in vivo. The peptide-modified PAS with promoted bioactivity and osteogenic differentiation in vitro as well as bone formation ability in vivo could be promising tissue engineering materials for repairing and regeneration of bone defects. Copyright © 2016 Elsevier B.V. All rights reserved.

Ribbon structure stabilized by C10 and C12 turns in αγ hybrid peptide.

PubMed

Wani, Naiem Ahmad; Kant, Rajni; Gupta, Vivek Kumar; Aravinda, Subrayashastry; Rai, Rajkishor

2016-04-01

The present study describes the synthesis and crystallographic analysis of αγ hybrid peptides, Boc-Gpn-L-Pro-NHMe (1), Boc-Aib-Gpn-L-Pro-NHMe (2), and Boc-L-Pro-Aib-Gpn-L-Pro-NHMe (3). Peptides 1 and 2 adopt expanded 12-membered (C12 ) helical turn over γα segment. Peptide 3 promotes the ribbon structure stabilized by type II β-turn (C10 ) followed by the expanded C12 helical γα turn. Both right-handed and left-handed helical conformations for Aib residue are observed in peptides 2 and 3, respectively. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Discobahamins A and B, new peptides from the Bahamian deep water marine sponge Discodermia sp.

PubMed

Gunasekera, S P; Pomponi, S A; McCarthy, P J

1994-01-01

Discobahamin A [1] and discobahamin B [2] are two bioactive peptides isolated from a new species of the Bahamian deep water marine sponge Discodermia. The discobahamins are inhibitors of the growth of Candida albicans, and the isolation and structure elucidation of 1 and 2 by nmr and chemical methods is described.

An exhaustive survey of regular peptide conformations using a new metric for backbone handedness (h)

PubMed Central

2017-01-01

The Ramachandran plot is important to structural biology as it describes a peptide backbone in the context of its dominant degrees of freedom—the backbone dihedral angles φ and ψ (Ramachandran, Ramakrishnan & Sasisekharan, 1963). Since its introduction, the Ramachandran plot has been a crucial tool to characterize protein backbone features. However, the conformation or twist of a backbone as a function of φ and ψ has not been completely described for both cis and trans backbones. Additionally, little intuitive understanding is available about a peptide’s conformation simply from knowing the φ and ψ values of a peptide (e.g., is the regular peptide defined by φ = ψ =  − 100°  left-handed or right-handed?). This report provides a new metric for backbone handedness (h) based on interpreting a peptide backbone as a helix with axial displacement d and angular displacement θ, both of which are derived from a peptide backbone’s internal coordinates, especially dihedral angles φ, ψ and ω. In particular, h equals sin(θ)d∕|d|, with range [−1, 1] and negative (or positive) values indicating left(or right)-handedness. The metric h is used to characterize the handedness of every region of the Ramachandran plot for both cis (ω = 0°) and trans (ω = 180°) backbones, which provides the first exhaustive survey of twist handedness in Ramachandran (φ, ψ) space. These maps fill in the ‘dead space’ within the Ramachandran plot, which are regions that are not commonly accessed by structured proteins, but which may be accessible to intrinsically disordered proteins, short peptide fragments, and protein mimics such as peptoids. Finally, building on the work of (Zacharias & Knapp, 2013), this report presents a new plot based on d and θ that serves as a universal and intuitive alternative to the Ramachandran plot. The universality arises from the fact that the co-inhabitants of such a plot include every possible peptide backbone including cis and trans backbones. The intuitiveness arises from the fact that d and θ provide, at a glance, numerous aspects of the backbone including compactness, handedness, and planarity. PMID:28533975

The Insect Pathogen Serratia marcescens Db10 Uses a Hybrid Non-Ribosomal Peptide Synthetase-Polyketide Synthase to Produce the Antibiotic Althiomycin

PubMed Central

Challis, Gregory L.; Stanley-Wall, Nicola R.; Coulthurst, Sarah J.

2012-01-01

There is a continuing need to discover new bioactive natural products, such as antibiotics, in genetically-amenable micro-organisms. We observed that the enteric insect pathogen, Serratia marcescens Db10, produced a diffusible compound that inhibited the growth of Bacillis subtilis and Staphyloccocus aureus. Mapping the genetic locus required for this activity revealed a putative natural product biosynthetic gene cluster, further defined to a six-gene operon named alb1–alb6. Bioinformatic analysis of the proteins encoded by alb1–6 predicted a hybrid non-ribosomal peptide synthetase-polyketide synthase (NRPS-PKS) assembly line (Alb4/5/6), tailoring enzymes (Alb2/3) and an export/resistance protein (Alb1), and suggested that the machinery assembled althiomycin or a related molecule. Althiomycin is a ribosome-inhibiting antibiotic whose biosynthetic machinery had been elusive for decades. Chromatographic and spectroscopic analyses confirmed that wild type S. marcescens produced althiomycin and that production was eliminated on disruption of the alb gene cluster. Construction of mutants with in-frame deletions of specific alb genes demonstrated that Alb2–Alb5 were essential for althiomycin production, whereas Alb6 was required for maximal production of the antibiotic. A phosphopantetheinyl transferase enzyme required for althiomycin biosynthesis was also identified. Expression of Alb1, a predicted major facilitator superfamily efflux pump, conferred althiomycin resistance on another, sensitive, strain of S. marcescens. This is the first report of althiomycin production outside of the Myxobacteria or Streptomyces and paves the way for future exploitation of the biosynthetic machinery, since S. marcescens represents a convenient and tractable producing organism. PMID:23028578

Tenascin-C mimetic Peptide nanofibers direct stem cell differentiation to osteogenic lineage.

PubMed

Sever, Melike; Mammadov, Busra; Guler, Mustafa O; Tekinay, Ayse B

2014-12-08

Extracellular matrix contains various signals for cell surface receptors that regulate cell fate through modulation of cellular activities such as proliferation and differentiation. Cues from extracellular matrix components can be used for development of new materials to control the stem cell fate. In this study, we achieved control of stem cell fate toward osteogenic commitment by using a single extracellular matrix element despite the contradictory effect of mechanical stiffness. For this purpose, we mimicked bone extracellular matrix by incorporating functional sequence of fibronectin type III domain from native tenascin-C on self-assembled peptide nanofibers. When rat mesenchymal stem cells (rMSCs) were cultured on these peptide nanofibers, alkaline phosphatase (ALP) activity and alizarin red staining indicated osteogenic differentiation even in the absence of osteogenic supplements. Moreover, expression levels of osteogenic marker genes were significantly enhanced revealed by quantitative real-time polymerase chain reaction (qRT-PCR), which showed the remarkable bioactive role of this nanofiber system on osteogenic differentiation. Overall, these results showed that tenascin-C mimetic peptides significantly enhanced the attachment, proliferation, and osteogenic differentiation of rMSCs even in the absence of any external bioactive factors and regardless of the suitable stiff mechanical properties normally required for osteogenic differentiation. Thus, these peptide nanofibers provide a promising new platform for bone regeneration.

Phosphopeptidomics Reveals Differential Phosphorylation States and Novel SxE Phosphosite Motifs of Neuropeptides in Dense Core Secretory Vesicles

NASA Astrophysics Data System (ADS)

Lietz, Christopher B.; Toneff, Thomas; Mosier, Charles; Podvin, Sonia; O'Donoghue, Anthony J.; Hook, Vivian

2018-05-01

Neuropeptides are vital for cell-cell communication and function in the regulation of the nervous and endocrine systems. They are generated by post-translational modification (PTM) steps resulting in small active peptides generated from prohormone precursors. Phosphorylation is a significant PTM for the bioactivity of neuropeptides. From the known diversity of distinct neuropeptide functions, it is hypothesized that the extent of phosphorylation varies among different neuropeptides. To assess this hypothesis, neuropeptide-containing dense core secretory vesicles from bovine adrenal medullary chromaffin cells were subjected to global phosphopeptidomics analyses by liquid chromatography (LC)-mass spectrometry (MS/MS). Phosphopeptides were identified directly by LC-MS/MS and indirectly by phosphatase treatment followed by LC-MS/MS. The data identified numerous phosphorylated peptides derived from neuropeptide precursors such as chromogranins, secretogranins, proenkephalin and pro-NPY. Phosphosite occupancies were observed at high and low levels among identified peptides and many of the high occupancy phosphopeptides represent prohormone-derived peptides with currently unknown bioactivities. Peptide sequence analyses demonstrated SxE as the most prevalent phosphorylation site motif, corresponding to phosphorylation sites of the Fam20C protein kinase known to be present in the secretory pathway. The range of high to low phosphosite occupancies for neuropeptides demonstrates cellular regulation of neuropeptide phosphorylation. [Figure not available: see fulltext.

Phosphopeptidomics Reveals Differential Phosphorylation States and Novel SxE Phosphosite Motifs of Neuropeptides in Dense Core Secretory Vesicles

NASA Astrophysics Data System (ADS)

Lietz, Christopher B.; Toneff, Thomas; Mosier, Charles; Podvin, Sonia; O'Donoghue, Anthony J.; Hook, Vivian

2018-03-01

Neuropeptides are vital for cell-cell communication and function in the regulation of the nervous and endocrine systems. They are generated by post-translational modification (PTM) steps resulting in small active peptides generated from prohormone precursors. Phosphorylation is a significant PTM for the bioactivity of neuropeptides. From the known diversity of distinct neuropeptide functions, it is hypothesized that the extent of phosphorylation varies among different neuropeptides. To assess this hypothesis, neuropeptide-containing dense core secretory vesicles from bovine adrenal medullary chromaffin cells were subjected to global phosphopeptidomics analyses by liquid chromatography (LC)-mass spectrometry (MS/MS). Phosphopeptides were identified directly by LC-MS/MS and indirectly by phosphatase treatment followed by LC-MS/MS. The data identified numerous phosphorylated peptides derived from neuropeptide precursors such as chromogranins, secretogranins, proenkephalin and pro-NPY. Phosphosite occupancies were observed at high and low levels among identified peptides and many of the high occupancy phosphopeptides represent prohormone-derived peptides with currently unknown bioactivities. Peptide sequence analyses demonstrated SxE as the most prevalent phosphorylation site motif, corresponding to phosphorylation sites of the Fam20C protein kinase known to be present in the secretory pathway. The range of high to low phosphosite occupancies for neuropeptides demonstrates cellular regulation of neuropeptide phosphorylation. [Figure not available: see fulltext.

A Novel Direct Factor Xa Inhibitory Peptide with Anti-Platelet Aggregation Activity from Agkistrodon acutus Venom Hydrolysates.

PubMed

Chen, Meimei; Ye, Xiaohui; Ming, Xin; Chen, Yahui; Wang, Ying; Su, Xingli; Su, Wen; Kong, Yi

2015-06-02

Snake venom is a natural substance that contains numerous bioactive proteins and peptides, nearly all of which have been identified over the last several decades. In this study, we subjected snake venom to enzymatic hydrolysis to identify previously unreported bioactive peptides. The novel peptide ACH-11 with the sequence LTFPRIVFVLG was identified with both FXa inhibition and anti-platelet aggregation activities. ACH-11 inhibited the catalytic function of FXa towards its substrate S-2222 via a mixed model with a Ki value of 9.02 μM and inhibited platelet aggregation induced by ADP and U46619 in a dose-dependent manner. Furthermore, ACH-11 exhibited potent antithrombotic activity in vivo. It reduced paralysis and death in an acute pulmonary thrombosis model by 90% and attenuated thrombosis weight in an arterio-venous shunt thrombosis model by 57.91%, both at a dose of 3 mg/kg. Additionally, a tail cutting bleeding time assay revealed that ACH-11 did not prolong bleeding time in mice at a dose of 3 mg/kg. Together, our results reveal that ACH-11 is a novel antithrombotic peptide exhibiting both FXa inhibition and anti-platelet aggregation activities, with a low bleeding risk. We believe that it could be a candidate or lead compound for new antithrombotic drug development.

Intracellular delivery of peptide nucleic acid and organic molecules using zeolite-L nanocrystals.

PubMed

Bertucci, Alessandro; Lülf, Henning; Septiadi, Dedy; Manicardi, Alex; Corradini, Roberto; De Cola, Luisa

2014-11-01

The design and synthesis of smart nanomaterials can provide interesting potential applications for biomedical purposes from bioimaging to drug delivery. Manufacturing multifunctional systems in a way to carry bioactive molecules, like peptide nucleic acids able to recognize specific targets in living cells, represents an achievement towards the development of highly selective tools for both diagnosis and therapeutics. This work describes a very first example of the use of zeolite nanocrystals as multifunctional nanocarriers to deliver simultaneously PNA and organic molecules into living cells. Zeolite-L nanocrystals are functionalized by covalently attaching the PNA probes onto the surface, while the channel system is filled with fluorescent guest molecules. The cellular uptake of the PNA/Zeolite-L hybrid material is then significantly increased by coating the whole system with a thin layer of biodegradable poly-L-lysine. The delivery of DAPI as a model drug molecule, inserted into the zeolite pores, is also demonstrated to occur in the cells, proving the multifunctional ability of the system. Using this zeolite nanosystem carrying PNA probes designed to target specific RNA sequences of interest in living cells could open new possibilities for theranostic and gene therapy applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Advancement and applications of peptide phage display technology in biomedical science.

PubMed

Wu, Chien-Hsun; Liu, I-Ju; Lu, Ruei-Min; Wu, Han-Chung

2016-01-19

Combinatorial phage library is a powerful research tool for high-throughput screening of protein interactions. Of all available molecular display techniques, phage display has proven to be the most popular approach. Screening phage-displayed random peptide libraries is an effective means of identifying peptides that can bind target molecules and regulate their function. Phage-displayed peptide libraries can be used for (i) B-cell and T-cell epitope mapping, (ii) selection of bioactive peptides bound to receptors or proteins, disease-specific antigen mimics, peptides bound to non-protein targets, cell-specific peptides, or organ-specific peptides, and (iii) development of peptide-mediated drug delivery systems and other applications. Targeting peptides identified using phage display technology may be useful for basic research and translational medicine. In this review article, we summarize the latest technological advancements in the application of phage-displayed peptide libraries to applied biomedical sciences.

Implications of the Maillard reaction on bovine alpha-lactalbumin and its proteolysis during in vitro infant digestion.

PubMed

Joubran, Yousef; Moscovici, Alice; Portmann, Reto; Lesmes, Uri

2017-06-21

This study investigated the functionality and digestibility of Maillard reaction products (MRPs) of alpha-lactalbumin (α-la), a major whey protein and component of infant formulas. The impact of different carbohydrates (glucose, galactose or galacto-oligosaccharides (GOS)) and heating duration was studied. SDS-PAGE, UV and color measurements monitored reaction extent, which varied between carbohydrates whereby galactose reacted more readily than glucose. Surface hydrophobicity and antioxidant capacity were found to be significantly (p < 0.05) higher following Maillard conjugation, with GOS-based MRPs elevating antioxidant capacity ∼50-fold compared to α-la. In addition, the digestive proteolysis of MRPs was evaluated using an infant in vitro gastro-duodenal model. SDS-PAGE analyses of digesta revealed Maillard conjugation generally increased α-la's susceptibility to proteolysis. Interestingly, GOS-based MRPs presented an optimization challenge, since heating for 12 h delayed proteolysis, while extended heating resulted in the highest susceptibility to proteolysis. Proteomic analyses further demonstrated the differences in enzymatic cleavage patterns and helped identify bioactive peptides rendered bioaccessible during the digestion of α-la or its MRPs. Bioinformatic mining of the proteomic data using PeptideRanker also gave rise to two potentially novel bioactive peptides, FQINNKIW and GINYWLAHKALCS. Finally, antioxidant capacity of luminal contents, measured by DPPH, revealed Maillard conjugation increased the antioxidant capacity of both gastric and duodenal digesta. Overall, this work draws a link between the Maillard reaction, digestive proteolysis and the bioaccessibility of bioactive peptides and antioxidant species in the infant alimentary canal. This could help rationally process infant formulas towards improved nutritional and extra-nutritional benefits.

Modeling of a C-end rule peptide adsorbed onto gold nanoparticles.

PubMed

Triguero, Jordi; Flores-Ortega, Alejandra; Zanuy, David; Alemán, Carlos

2018-01-01

The RPAR peptide, a prototype C-end Rule (CendR) sequence that binds to neuropilin-1 (NRP-1), has potential therapeutic uses as internalization trigger in anticancer nanodevices. Recently, the functionalization of gold nanoparticles with CendR peptides has been proved to be a successful strategy to target the NRP-1 receptor in prostate cancer cells. In this work, we investigate the influence of two gold surface facets, (100) and (111), on the conformational preferences of RPAR using molecular dynamics simulations. Both clustering and conformational analyses revealed that the peptide backbone becomes very rigid upon adsorption onto gold, which is a very fast and favored process, the only flexibility being attributed to the side chains of the two Arg residues. Thus, the different components of RPAR tend to adopt an elongated shape, which is characterized by the pseudo-extended conformation of both the backbone and the Arg side chains. This conformation is very different from the already known bioactive conformation, indicating that RPAR is drastically affected by the substrate. Interestingly, the preferred conformations of the peptide adsorbed onto gold facets are not stabilized by salt bridges and/or specific intramolecular hydrogen bonds, which represent an important difference with respect to the conformations found in other environments (e.g. the peptide in solution and interacting with NRP-1 receptor). However, the conformational changes induced by the substrate are not detrimental for the use of gold nanoparticles as appropriate vehicles for the transport and targeted delivery of the RPAR. Thus, once their high affinity for the NRP-1 receptor induces the targeted delivery of the elongated peptide molecules from the gold nanoparticles, the lack of intramolecular interactions facilitates their evolution towards the bioactive conformation, increasing the therapeutic efficacy of the peptide. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

Construction of hybrid peptide synthetases by module and domain fusions

PubMed Central

Mootz, Henning D.; Schwarzer, Dirk; Marahiel, Mohamed A.

2000-01-01

Nonribosomal peptide synthetases are modular enzymes that assemble peptides of diverse structures and important biological activities. Their modular organization provides a great potential for the rational design of novel compounds by recombination of the biosynthetic genes. Here we describe the extension of a dimodular system to trimodular ones based on whole-module fusion. The recombinant hybrid enzymes were purified to monitor product assembly in vitro. We started from the first two modules of tyrocidine synthetase, which catalyze the formation of the dipeptide dPhe-Pro, to construct such hybrid systems. Fusion of the second, proline-specific module with the ninth and tenth modules of the tyrocidine synthetases, specific for ornithine and leucine, respectively, resulted in dimodular hybrid enzymes exhibiting the combined substrate specificities. The thioesterase domain was fused to the terminal module. Upon incubation of these dimodular enzymes with the first tyrocidine module, TycA, incorporating dPhe, the predicted tripeptides dPhe-Pro-Orn and dPhe-Pro-Leu were obtained at rates of 0.15 min-1 and 2.1 min-1. The internal thioesterase domain was necessary and sufficient to release the products from the hybrid enzymes and thereby facilitate a catalytic turnover. Our approach of whole-module fusion is based on an improved definition of the fusion sites and overcomes the recently discovered editing function of the intrinsic condensation domains. The stepwise construction of hybrid peptide synthetases from catalytic subunits reinforces the inherent potential for the synthesis of novel, designed peptides. PMID:10811885

Construction of hybrid peptide synthetases by module and domain fusions.

PubMed

Mootz, H D; Schwarzer, D; Marahiel, M A

2000-05-23

Nonribosomal peptide synthetases are modular enzymes that assemble peptides of diverse structures and important biological activities. Their modular organization provides a great potential for the rational design of novel compounds by recombination of the biosynthetic genes. Here we describe the extension of a dimodular system to trimodular ones based on whole-module fusion. The recombinant hybrid enzymes were purified to monitor product assembly in vitro. We started from the first two modules of tyrocidine synthetase, which catalyze the formation of the dipeptide dPhe-Pro, to construct such hybrid systems. Fusion of the second, proline-specific module with the ninth and tenth modules of the tyrocidine synthetases, specific for ornithine and leucine, respectively, resulted in dimodular hybrid enzymes exhibiting the combined substrate specificities. The thioesterase domain was fused to the terminal module. Upon incubation of these dimodular enzymes with the first tyrocidine module, TycA, incorporating dPhe, the predicted tripeptides dPhe-Pro-Orn and dPhe-Pro-Leu were obtained at rates of 0.15 min(-1) and 2.1 min(-1). The internal thioesterase domain was necessary and sufficient to release the products from the hybrid enzymes and thereby facilitate a catalytic turnover. Our approach of whole-module fusion is based on an improved definition of the fusion sites and overcomes the recently discovered editing function of the intrinsic condensation domains. The stepwise construction of hybrid peptide synthetases from catalytic subunits reinforces the inherent potential for the synthesis of novel, designed peptides.

Synthetic fermentation of bioactive non-ribosomal peptides without organisms, enzymes or reagents

NASA Astrophysics Data System (ADS)

Huang, Yi-Lin; Bode, Jeffrey W.

2014-10-01

Microbial fermentation can rapidly provide potent compounds that can be easily screened for biological activity, and the active components can be isolated. Its success in drug discovery has inspired extensive efforts to modulate and control the products. In this Article, we document a ‘synthetic fermentation’ of bioactive, unnatural peptides ‘grown’ from small building blocks in water using amide-forming ligations. No organisms, enzymes or reagents are needed. The sequences, structures and compositions of the products can be modulated by adjusting the building blocks and conditions. No specialized knowledge of organic chemistry or handling of toxic material is required to produce complex organic molecules. The ‘fermentations’ can be conducted in arrays and screened for biological activity without isolation or workup. As a proof-of-concept, about 6,000 unnatural peptides were produced from just 23 building blocks, from which a hepatitis C virus NS3/4A protease inhibitor with a half-maximum inhibitory concentration of 1.0 μM was identified and characterized.

Apricot and other seed stones: amygdalin content and the potential to obtain antioxidant, angiotensin I converting enzyme inhibitor and hypocholesterolemic peptides.

PubMed

García, M C; González-García, E; Vásquez-Villanueva, R; Marina, M L

2016-11-09

Stones from olives and Prunus genus fruits are cheap and sustainable sources of proteins and could be potential sources of bioactive peptides. The main limitation to the use of these seeds is the presence of amygdalin. This work proposes to determine amygdalin in olive and Prunus seeds and in protein isolates obtained from them. Moreover, antioxidant, angiotensin I converting enzyme (ACE) inhibitor, and hypocholesterolemic properties will be evaluated in hydrolysates obtained from these seeds. Despite some seeds contained amygdalin, all protein isolates were free of this substance. Two different procedures to obtain bioactive peptides from protein isolates were examined: gastrointestinal digestion and processing with Alcalase, Flavourzyme or Thermolysin. Higher antioxidant, ACE inhibitor and hypocholesterolemic activities were observed when proteins were processed with Alcalase, Flavourzyme or Thermolysin. The highest antioxidant and ACE inhibitor capacities were observed for the Prunus genus seed hydrolysates while the highest capacity to reduce micellar cholesterol solubility was observed for the apricot and olive seed hydrolysates.

99mTc-HYNIC-TNF analogs (WH701) derived from phage display peptide libraries for imaging TNF-receptor-positive ovarian carcinoma: preclinical evaluation

NASA Astrophysics Data System (ADS)

Xiang, Yan; Xia, Jinsong; Wu, H.; Li, H. F.

2002-04-01

Radiolabeled bioactive peptides which bind specifically to surface receptors over expressed in tumor cells are considered as alternatives for tumor detection with ECT. In this investigation, 99mTc-hydrazinonicotinyl - TNF analogs (WH701) was labeled using ethylenediaminediacetic acid (EDDA) as coligand (a number of TNF analogs had been selected and synthesized using random phage-display peptides library in our lab) and Pharmacokinetics and feasibility studies were performed.

Bioactive Mimetics of Conotoxins and other Venom Peptides

PubMed Central

Duggan, Peter J.; Tuck, Kellie L.

2015-01-01

Ziconotide (Prialt®), a synthetic version of the peptide ω-conotoxin MVIIA found in the venom of a fish-hunting marine cone snail Conus magnus, is one of very few drugs effective in the treatment of intractable chronic pain. However, its intrathecal mode of delivery and narrow therapeutic window cause complications for patients. This review will summarize progress in the development of small molecule, non-peptidic mimics of Conotoxins and a small number of other venom peptides. This will include a description of how some of the initially designed mimics have been modified to improve their drug-like properties. PMID:26501323

A novel transferrin receptor-targeted hybrid peptide disintegrates cancer cell membrane to induce rapid killing of cancer cells

PubMed Central

2011-01-01

Background Transferrin receptor (TfR) is a cell membrane-associated glycoprotein involved in the cellular uptake of iron and the regulation of cell growth. Recent studies have shown the elevated expression levels of TfR on cancer cells compared with normal cells. The elevated expression levels of this receptor in malignancies, which is the accessible extracellular protein, can be a fascinating target for the treatment of cancer. We have recently designed novel type of immunotoxin, termed "hybrid peptide", which is chemically synthesized and is composed of target-binding peptide and lytic peptide containing cationic-rich amino acids components that disintegrates the cell membrane for the cancer cell killing. The lytic peptide is newly designed to induce rapid killing of cancer cells due to conformational change. In this study, we designed TfR binding peptide connected with this novel lytic peptide and assessed the cytotoxic activity in vitro and in vivo. Methods In vitro: We assessed the cytotoxicity of TfR-lytic hybrid peptide for 12 cancer and 2 normal cell lines. The specificity for TfR is demonstrated by competitive assay using TfR antibody and siRNA. In addition, we performed analysis of confocal fluorescence microscopy and apoptosis assay by Annexin-V binding, caspase activity, and JC-1 staining to assess the change in mitochondria membrane potential. In vivo: TfR-lytic was administered intravenously in an athymic mice model with MDA-MB-231 cells. After three weeks tumor sections were histologically analyzed. Results The TfR-lytic hybrid peptide showed cytotoxic activity in 12 cancer cell lines, with IC50 values as low as 4.0-9.3 μM. Normal cells were less sensitive to this molecule, with IC50 values > 50 μM. Competition assay using TfR antibody and knockdown of this receptor by siRNA confirmed the specificity of the TfR-lytic hybrid peptide. In addition, it was revealed that this molecule can disintegrate the cell membrane of T47D cancer cells just in 10 min, to effectively kill these cells and induce approximately 80% apoptotic cell death but not in normal cells. The intravenous administration of TfR-lytic peptide in the athymic mice model significantly inhibited tumor progression. Conclusions TfR-lytic peptide might provide a potent and selective anticancer therapy for patients. PMID:21849092

Triggering nanoparticle surface ligand rearrangement via external stimuli: light-based actuation of biointerfaces

NASA Astrophysics Data System (ADS)

Tang, Zhenghua; Lim, Chang-Keun; Palafox-Hernandez, J. Pablo; Drew, Kurt L. M.; Li, Yue; Swihart, Mark T.; Prasad, Paras N.; Walsh, Tiffany R.; Knecht, Marc R.

2015-08-01

Bio-molecular non-covalent interactions provide a powerful platform for material-specific self-organization in aqueous media. Here, we introduce a strategy that integrates a synthetic optically-responsive motif with a materials-binding peptide to enable remote actuation. Specifically, we linked a photoswitchable azobenzene moiety to either terminus of a Au-binding peptide. We employed these hybrid molecules as capping agents for synthesis of Au nanoparticles. Integrated experiments and molecular simulations showed that the hybrid molecules maintained both of their functions, i.e. binding to Au and optically-triggered reconfiguration. The azobenzene unit was optically switched reversibly between trans and cis states while adsorbed on the particle surface. Upon switching, the conformation of the peptide component of the molecule also changed. This highlights the interplay between the surface adsorption and conformational switching that will be pivotal to the creation of actuatable nanoparticle bio-interfaces, and paves the way toward multifunctional peptide hybrids that can produce stimuli responsive nanoassemblies.Bio-molecular non-covalent interactions provide a powerful platform for material-specific self-organization in aqueous media. Here, we introduce a strategy that integrates a synthetic optically-responsive motif with a materials-binding peptide to enable remote actuation. Specifically, we linked a photoswitchable azobenzene moiety to either terminus of a Au-binding peptide. We employed these hybrid molecules as capping agents for synthesis of Au nanoparticles. Integrated experiments and molecular simulations showed that the hybrid molecules maintained both of their functions, i.e. binding to Au and optically-triggered reconfiguration. The azobenzene unit was optically switched reversibly between trans and cis states while adsorbed on the particle surface. Upon switching, the conformation of the peptide component of the molecule also changed. This highlights the interplay between the surface adsorption and conformational switching that will be pivotal to the creation of actuatable nanoparticle bio-interfaces, and paves the way toward multifunctional peptide hybrids that can produce stimuli responsive nanoassemblies. Electronic supplementary information (ESI) available: Additional modeling analysis, QCM analysis, UV-vis and CD spectroscopy data. See DOI: 10.1039/C5NR02311D

Intra-amniotic administration (Gallus gallus) of cicer arietinum and lens culinaris prebiotics extracts and duck egg white peptides affects calcium status and intestinal functionality

USDA-ARS?s Scientific Manuscript database

Calcium (Ca) is one of the most abundant inorganic elements in the human body and has many important physiological roles. Prebiotics and bioactive peptides are two important substances used to promote calcium uptake. However, the difference in mechanisms of the calcium uptake from these two suppleme...

Molecular Innovations Toward Theranostics of Aggressive Prostate Cancer

DTIC Science & Technology

2016-09-01

conjugation to drugs In preparation 4 Scope and limitations of ligation of peptides bearing an aldehyde or ketone group with dendrimers displaying...that triazinylhydrazine condense with the carbonyl groups of aldehydes and ketones . The intrinsic advantage of using a triazine comes with the...reacts efficiently with simple aldehydes and ketones , and with bioactives including the drug doxorubicin and bruceantin. Peptides bearing an N

ACE Inhibitory and Antioxidant Activities of Collagen Hydrolysates from the Ribbon Jellyfish (Chrysaora sp.)

PubMed Central

Latiff, Aishah Abd; Gan, Chee-Yuen; Abedin, Md. Zainul; Alias, Abd Karim

2014-01-01

Summary Collagen isolated from the ribbon jellyfish (Chrysaora sp.) was hydrolysed using three different proteases (i.e. trypsin, alcalase and Protamex) to obtain bioactive peptides. Angiotensin-I-converting enzyme (ACE) inhibitory activity and antioxidant activities (i.e. ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity) of the peptides were measured and compared, and the effect of the duration of hydrolysis on the bioactivity (ACE inhibitory and antioxidant activities) of peptides was also evaluated. FRAP activity was the highest in Protamex-induced (25–27 mM) and trypsin-induced hydrolysates (24–26 mM) at 7 and 9 h, respectively. Conversely, hydrolysates produced by trypsin for 1 and 3 h showed the highest DPPH radical scavenging activities (94 and 92%, respectively). Trypsin-induced hydrolysates (at 3 h) also showed the highest ACE inhibitory activity (89%). The peptide sequences with the highest activities were identified using tandem mass spectrometry, and the results show that the hydrolysates had a high content of hydrophobic amino acids as well as unique amino acid sequences, which likely contribute to their biological activities. PMID:27904323

Covalent Functionalization of NiTi Surfaces with Bioactive Peptide Amphiphile Nanofibers

PubMed Central

Sargeant, Timothy D.; Rao, Mukti S.; Koh, Chung-Yan

2009-01-01

Surface modification enables the creation of bioactive implants using traditional material substrates without altering the mechanical properties of the bulk material. For applications such as bone plates and stents, it is desirable to modify the surface of metal alloy substrates to facilitate cellular attachment, proliferation, and possibly differentiation. In this work we present a general strategy for altering the surface chemistry of nickel-titanium shape memory alloy (NiTi) in order to covalently attach self-assembled peptide amphiphile (PA) nanofibers with bioactive functions. Bioactivity in the systems studied here includes biological adhesion and proliferation of osteoblast and endothelial cell types. The optimized surface treatment creates a uniform TiO2 layer with low levels of Ni on the NiTi surface, which is subsequently covered with an aminopropylsilane coating using a novel, lower temperature vapor deposition method. This method produces an aminated surface suitable for covalent attachment of PA molecules containing terminal carboxylic acid groups. The functionalized NiTi surfaces have been characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and atomic force microscopy (AFM). These techniques offer evidence that the treated metal surfaces consist primarily of TiO2 with very little Ni, and also confirm the presence of the aminopropylsilane overlayer. Self-assembled PA nanofibers presenting the biological peptide adhesion sequence Arg-Gly-Asp-Ser are capable of covalently anchoring to the treated substrate, as demonstrated by spectrofluorimetry and AFM. Cell culture and scanning electron microscopy (SEM) demonstrate cellular adhesion, spreading, and proliferation on these functionalized metal surfaces. Furthermore, these experiments demonstrate that covalent attachment is crucial for creating robust PA nanofiber coatings, leading to confluent cell monolayers. PMID:18083225

Features of Modularly Assembled Compounds That Impart Bioactivity Against an RNA Target

PubMed Central

Rzuczek, Suzanne G.; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A.; Kodadek, Thomas; Disney, Matthew D.

2013-01-01

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the non-coding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)exp. Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). Based on activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely PTAs, are optimal. Notably, we determined that r(CUG)exp is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived and faster on rates than the protein that binds r(CUG)exp, the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets. PMID:24032410

Features of modularly assembled compounds that impart bioactivity against an RNA target.

PubMed

Rzuczek, Suzanne G; Gao, Yu; Tang, Zhen-Zhi; Thornton, Charles A; Kodadek, Thomas; Disney, Matthew D

2013-10-18

Transcriptomes provide a myriad of potential RNAs that could be the targets of therapeutics or chemical genetic probes of function. Cell-permeable small molecules, however, generally do not exploit these targets, owing to the difficulty in the design of high affinity, specific small molecules targeting RNA. As part of a general program to study RNA function using small molecules, we designed bioactive, modularly assembled small molecules that target the noncoding expanded RNA repeat that causes myotonic dystrophy type 1 (DM1), r(CUG)(exp). Herein, we present a rigorous study to elucidate features in modularly assembled compounds that afford bioactivity. Different modular assembly scaffolds were investigated, including polyamines, α-peptides, β-peptides, and peptide tertiary amides (PTAs). On the basis of activity as assessed by improvement of DM1-associated defects, stability against proteases, cellular permeability, and toxicity, we discovered that constrained backbones, namely, PTAs, are optimal. Notably, we determined that r(CUG)(exp) is the target of the optimal PTA in cellular models and that the optimal PTA improves DM1-associated defects in a mouse model. Biophysical analyses were employed to investigate potential sources of bioactivity. These investigations show that modularly assembled compounds have increased residence times on their targets and faster on rates than the RNA-binding modules from which they were derived. Moreover, they have faster on rates than the protein that binds r(CUG)(exp), the inactivation of which gives rise to DM1-associated defects. These studies provide information about features of small molecules that are programmable for targeting RNA, allowing for the facile optimization of therapeutics or chemical probes against other cellular RNA targets.

Discovery Strategies of Bioactive Compounds Synthesized by Nonribosomal Peptide Synthetases and Type-I Polyketide Synthases Derived from Marine Microbiomes

PubMed Central

Amoutzias, Grigoris D.; Chaliotis, Anargyros; Mossialos, Dimitris

2016-01-01

Considering that 70% of our planet’s surface is covered by oceans, it is likely that undiscovered biodiversity is still enormous. A large portion of marine biodiversity consists of microbiomes. They are very attractive targets of bioprospecting because they are able to produce a vast repertoire of secondary metabolites in order to adapt in diverse environments. In many cases secondary metabolites of pharmaceutical and biotechnological interest such as nonribosomal peptides (NRPs) and polyketides (PKs) are synthesized by multimodular enzymes named nonribosomal peptide synthetases (NRPSes) and type-I polyketide synthases (PKSes-I), respectively. Novel findings regarding the mechanisms underlying NRPS and PKS evolution demonstrate how microorganisms could leverage their metabolic potential. Moreover, these findings could facilitate synthetic biology approaches leading to novel bioactive compounds. Ongoing advances in bioinformatics and next-generation sequencing (NGS) technologies are driving the discovery of NRPs and PKs derived from marine microbiomes mainly through two strategies: genome-mining and metagenomics. Microbial genomes are now sequenced at an unprecedented rate and this vast quantity of biological information can be analyzed through genome mining in order to identify gene clusters encoding NRPSes and PKSes of interest. On the other hand, metagenomics is a fast-growing research field which directly studies microbial genomes and their products present in marine environments using culture-independent approaches. The aim of this review is to examine recent developments regarding discovery strategies of bioactive compounds synthesized by NRPS and type-I PKS derived from marine microbiomes and to highlight the vast diversity of NRPSes and PKSes present in marine environments by giving examples of recently discovered bioactive compounds. PMID:27092515

Immobilization of Trypsin in Lignocellulosic Waste Material to Produce Peptides with Bioactive Potential from Whey Protein

PubMed Central

Bassan, Juliana Cristina; de Souza Bezerra, Thaís Milena; Peixoto, Guilherme; da Cruz, Clariana Zanutto Paulino; Galán, Julián Paul Martínez; Vaz, Aline Buda dos Santos; Garrido, Saulo Santesso; Filice, Marco; Monti, Rubens

2016-01-01

In this study, trypsin (Enzyme Comission 3.4.21.4) was immobilized in a low cost, lignocellulosic support (corn cob powder—CCP) with the goal of obtaining peptides with bioactive potential from cheese whey. The pretreated support was activated with glyoxyl groups, glutaraldehyde and IDA-glyoxyl. The immobilization yields of the derivatives were higher than 83%, and the retention of catalytic activity was higher than 74%. The trypsin-glyoxyl-CCP derivative was thermally stable at 65 °C, a value that was 1090-fold higher than that obtained with the free enzyme. The trypsin-IDA-glyoxyl-CCP and trypsin-glutaraldehyde-CCP derivatives had thermal stabilities that were 883- and five-fold higher, respectively, then those obtained with the free enzyme. In the batch experiments, trypsin-IDA-glyoxyl-CCP retained 91% of its activity and had a degree of hydrolysis of 12.49%, while the values for trypsin-glyoxyl-CCP were 87% and 15.46%, respectively. The stabilized derivative trypsin-glyoxyl-CCP was also tested in an upflow packed-bed reactor. The hydrodynamic characterization of this reactor was a plug flow pattern, and the kinetics of this system provided a relative activity of 3.04 ± 0.01 U·g−1 and an average degree of hydrolysis of 23%, which were suitable for the production of potentially bioactive peptides. PMID:28773482

The purification and characterization of an 88-kDa Porphyromonas endodontalis 35406 protease.

PubMed

Rosen, G; Shoshani, M; Naor, R; Sela, M N

2001-12-01

A Porphyromonas endodontalis ATCC 35406 protease was purified from Triton X-114 cell extracts by preparative SDS-PAGE followed by electroelution. The purified enzyme exhibits a molecular size of 88 kDa and was dissociated into two polypeptides of 43 and 41 kDa upon heating in the presence of sodium dodecyl sulfate with or without a reducing agent. The protease (pH optimum 7.5-8.0) degraded the extracellular matrix proteins fibrinogen and fibronectin. Collagen IV was also degraded at 37 degrees C but not at 28 degrees C. The protease also cleaved the bioactive peptide angiotensin at amino acid residue phenylalanine-8 and tyrosine-4 but failed to hydrolyze bradykinin, vasopressin and synthetic chromogenic substrates with phenylalanine or tyrosine at the P1 position. In addition, two peptidases were detected in P. endodontalis cells: a proline aminopeptidase that remained associated with the cell pellet after detergent extraction and peptidase/s that partitioned into the Triton X-114 phase after phase separation and degraded the bioactive peptides bradykinin and vasopressin. These P. endodontalis peptidases and proteases may play an important role in both the nutrition and pathogenicity of these assacharolytic microorganisms. The inactivation of bioactive peptides and degradation of extracellular matrix proteins by bacterial enzymes may contribute to the damage of host tissues accompanied with endodontic infections.

Is the structural diversity of tripeptides sufficient for developing functional food additives with satisfactory multiple bioactivities?

NASA Astrophysics Data System (ADS)

Wang, Jian-Hui; Liu, Yong-Le; Ning, Jing-Heng; Yu, Jian; Li, Xiang-Hong; Wang, Fa-Xiang

2013-05-01

Multifunctional peptides have attracted increasing attention in the food science community because of their therapeutic potential, low toxicity and rapid intestinal absorption. However, previous study demonstrated that the limited structural variations make it difficult to optimize dipeptide molecules in a good balance between desirable and undesirable properties (F. Tian, P. Zhou, F. Lv, R. Song, Z. Li, J. Pept. Sci. 13 (2007) 549-566). In the present work, we attempt to answer whether the structural diversity is sufficient for a tripeptide to have satisfactory multiple bioactivities. Statistical test, structural examination and energetic analysis confirm that peptides of three amino acids long can bind tightly to human angiotensin converting enzyme (ACE) and thus exert significant antihypertensive efficacy. Further quantitative structure-activity relationship (QSAR) modeling and prediction of all 8000 possible tripeptides reveal that their ACE-inhibitory potency exhibits a good (positive) relationship to antioxidative activity, but has only a quite modest correlation with bitterness. This means that it is possible to find certain tripeptide entities possessing the optimal combination of strong ACE-inhibitory potency, high antioxidative activity and weak bitter taste, which are the promising candidates for developing multifunctional food additives with satisfactory multiple bioactivities. The marked difference between dipeptide and tripeptide can be attributed to the fact that the structural diversity of peptides increases dramatically with a slight change in sequence length.

Structural studies of polypeptides: Mechanism of immunoglobin catalysis and helix propagation in hybrid sequence, disulfide containing peptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storrs, Richard Wood

1992-08-01

Catalytic immunoglobin fragments were studied Nuclear Magnetic Resonance spectroscopy to identify amino acid residues responsible for the catalytic activity. Small, hybrid sequence peptides were analyzed for helix propagation following covalent initiation and for activity related to the protein from which the helical sequence was derived. Hydrolysis of p-nitrophenyl carbonates and esters by specific immunoglobins is thought to involve charge complementarity. The pK of the transition state analog P-nitrophenyl phosphate bound to the immunoglobin fragment was determined by 31P-NMR to verify the juxtaposition of a positively charged amino acid to the binding/catalytic site. Optical studies of immunoglobin mediated photoreversal of cis,more » syn cyclobutane thymine dimers implicated tryptophan as the photosensitizing chromophore. Research shows the chemical environment of a single tryptophan residue is altered upon binding of the thymine dimer. This tryptophan residue was localized to within 20 Å of the binding site through the use of a nitroxide paramagnetic species covalently attached to the thymine dimer. A hybrid sequence peptide was synthesized based on the bee venom peptide apamin in which the helical residues of apamin were replaced with those from the recognition helix of the bacteriophage 434 repressor protein. Oxidation of the disufide bonds occured uniformly in the proper 1-11, 3-15 orientation, stabilizing the 434 sequence in an α-helix. The glycine residue stopped helix propagation. Helix propagation in 2,2,2-trifluoroethanol mixtures was investigated in a second hybrid sequence peptide using the apamin-derived disulfide scaffold and the S-peptide sequence. The helix-stop signal previously observed was not observed in the NMR NOESY spectrum. Helical connectivities were seen throughout the S-peptide sequence. The apamin/S-peptide hybrid binded to the S-protein (residues 21-166 of ribonuclease A) and reconstituted enzymatic activity.« less

Structural studies of polypeptides: Mechanism of immunoglobin catalysis and helix propagation in hybrid sequence, disulfide containing peptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storrs, R.W.

1992-08-01

Catalytic immunoglobin fragments were studied Nuclear Magnetic Resonance spectroscopy to identify amino acid residues responsible for the catalytic activity. Small, hybrid sequence peptides were analyzed for helix propagation following covalent initiation and for activity related to the protein from which the helical sequence was derived. Hydrolysis of p-nitrophenyl carbonates and esters by specific immunoglobins is thought to involve charge complementarity. The pK of the transition state analog P-nitrophenyl phosphate bound to the immunoglobin fragment was determined by [sup 31]P-NMR to verify the juxtaposition of a positively charged amino acid to the binding/catalytic site. Optical studies of immunoglobin mediated photoreversal ofmore » cis, syn cyclobutane thymine dimers implicated tryptophan as the photosensitizing chromophore. Research shows the chemical environment of a single tryptophan residue is altered upon binding of the thymine dimer. This tryptophan residue was localized to within 20 [Angstrom] of the binding site through the use of a nitroxide paramagnetic species covalently attached to the thymine dimer. A hybrid sequence peptide was synthesized based on the bee venom peptide apamin in which the helical residues of apamin were replaced with those from the recognition helix of the bacteriophage 434 repressor protein. Oxidation of the disufide bonds occured uniformly in the proper 1-11, 3-15 orientation, stabilizing the 434 sequence in an [alpha]-helix. The glycine residue stopped helix propagation. Helix propagation in 2,2,2-trifluoroethanol mixtures was investigated in a second hybrid sequence peptide using the apamin-derived disulfide scaffold and the S-peptide sequence. The helix-stop signal previously observed was not observed in the NMR NOESY spectrum. Helical connectivities were seen throughout the S-peptide sequence. The apamin/S-peptide hybrid binded to the S-protein (residues 21-166 of ribonuclease A) and reconstituted enzymatic activity.« less

A rational nomenclature for naming peptide toxins from spiders and other venomous animals.

PubMed

King, Glenn F; Gentz, Margaret C; Escoubas, Pierre; Nicholson, Graham M

2008-08-01

Molecular toxinology research was initially driven by an interest in the small subset of animal toxins that are lethal to humans. However, the realization that many venomous creatures possess a complex repertoire of bioactive peptide toxins with potential pharmaceutical and agrochemical applications has led to an explosion in the number of new peptide toxins being discovered and characterized. Unfortunately, this increased awareness of peptide-toxin diversity has not been matched by the development of a generic nomenclature that enables these toxins to be rationally classified, catalogued, and compared. In this article, we introduce a rational nomenclature that can be applied to the naming of peptide toxins from spiders and other venomous animals.

Hydrolytic breakdown of lactoferricin by lactic acid bacteria.

PubMed

Paul, Moushumi; Somkuti, George A

2010-02-01

Lactoferricin is a 25-amino acid antimicrobial peptide fragment that is liberated by pepsin digestion of lactoferrin present in bovine milk. Along with its antibacterial properties, lactoferricin has also been reported to have immunostimulatory, antiviral, and anticarcinogenic effects. These attributes provide lactoferricin and other natural bioactive peptides with the potential to be functional food ingredients that can be used by the food industry in a variety of applications. At present, commercial uses of these types of compounds are limited by the scarcity of information on their ability to survive food processing environments. We have monitored the degradation of lactoferricin during its incubation with two types of lactic acid bacteria used in the yogurt-making industry, Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus, with the aim of assessing the stability of this milk protein-derived peptide under simulated yogurt-making conditions. Analysis of the hydrolysis products isolated from these experiments indicates degradation of this peptide near neutral pH by lactic acid bacteria-associated peptidases, the extent of which was influenced by the bacterial strain used. However, the data also showed that compared to other milk-derived bioactive peptides that undergo complete degradation under these conditions, the 25-amino acid lactoferricin is apparently more resistant, with approximately 50% of the starting material remaining after 4 h of incubation. These findings imply that lactoferricin, as a natural milk protein-derived peptide, has potential applications in the commercial production of yogurt-like fermented dairy products as a multi-functional food ingredient.

Antibacterial and antiproliferative peptides in synbiotic yogurt-Release and stability during refrigerated storage.

PubMed

Sah, B N P; Vasiljevic, T; McKechnie, S; Donkor, O N

2016-06-01

The search for alternative therapeutics is on the rise due to the extensive increase in bacterial resistance to various conventional antibiotics and side effects of conventional cancer therapies. Bioactive peptides released from natural sources such as dairy foods by lactic acid bacteria have received attention as a potential source of biotherapeutic peptides. However, liberation of peptides in yogurt depends on proteolytic activities of the cultures used. Thus, this research was conducted to establish generation of inhibitory peptides in yogurt against pathogenic bacteria and cancer cells during storage at 4°C for 28d. Water-soluble crude peptide extracts were prepared by high-speed centrifugation of plain and probiotic yogurts supplemented with or without pineapple peel powder (PPP). The inhibition zones against Escherichia coli and Staphylococcus aureus by PPP-fortified probiotic yogurt at 28d of storage were, respectively, 25.89 and 11.72mm in diameter, significantly higher than that of nonsupplemented control yogurts. Antiproliferative activity against HT29 colon cancer cells was also significantly higher in probiotic yogurt with PPP than in nonsupplemented probiotic yogurt. Overall, crude water-soluble peptide extracts of the probiotic yogurt with PPP possessed stronger inhibitory activities against bacteria and cancer cells than controls, and these activities were maintained during storage. However, activities were lowered substantially during in vitro gastrointestinal digestion. These findings support the possibility of utilizing dairy-derived bioactive peptides in the development of a superior alternative to the current generation of antibacterial and anticancer agents, as well as a functional ingredient in foods, nutraceuticals, and pharmaceuticals. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Theranostic Value of Multimers: Lessons Learned from Trimerization of Neurotensin Receptor Ligands and Other Targeting Vectors

PubMed Central

Maschauer, Simone; Einsiedel, Jürgen; Reich, Dominik; Hübner, Harald; Gmeiner, Peter; Wester, Hans-Jürgen; Prante, Olaf; Notni, Johannes

2017-01-01

Neurotensin receptor 1 (NTS1) is overexpressed on a variety of cancer entities; for example, prostate cancer, ductal pancreatic adenocarcinoma, and breast cancer. Therefore, it represents an interesting target for the diagnosis of these cancers types by positron emission tomography (PET). The metabolically-stabilized neurotensin (NT) derivative peptide Nlys8-Lys9-Pro10-Tyr11-Tle12-Leu13-OH was elongated at the N-terminus with 6-azido norleucine and coupled with the 1,4,7-triazacyclononane-1,4,7-tris[(2-carboxyethyl)methylenephosphinic acid] (TRAP) chelator TRAP(alkyne)3 in order to synthesize a NT trimer with subnanomolar affinity and high stability. The 68Ga-labeled peptide [68Ga]Ga-TRAP(NT4)3 was characterized in vitro using the NTS1-expressing human colorectal adenocarcinoma cell line HT29. It displayed fast and high internalization rates of >90%, but also fast efflux rates of 50% over 15 min. In vivo, [68Ga]Ga-TRAP(NT4)3 showed moderate HT29 tumor uptake values of 1.7 %ID/g at 60 min post-injection (p.i.), but also high uptake and retention in the kidneys and liver. A comparison of data for trimer/monomer pairs of NT ligands and other targeting vectors (peptides and peptoids targeting integrins αvβ3, α5β1, and αvβ6, the PSMA-ligand DUPA (2-[3-(1,3-dicarboxypropyl)-ureido]pentanedioic acid), and nitroimidazoles targeting hypoxia) revealed that multimers always exhibit higher target affinities and tumor uptake, but not necessarily improved tumor-to-tissue ratios. Thus, although in vitro data are not suitable for prediction of in vivo performance, multimers are potentially superior to monomers, particularly for applications where high tumor accumulation is crucial. PMID:28287433

Two Bioactive Molecular Weight Fractions of a Conditioned Medium Enhance RPE Cell Survival on Age-Related Macular Degeneration and Aged Bruch's Membrane

PubMed Central

Sugino, Ilene K.; Sun, Qian; Springer, Carola; Cheewatrakoolpong, Noounanong; Liu, Tong; Li, Hong; Zarbin, Marco A.

2016-01-01

Purpose To characterize molecular weight fractions of bovine corneal endothelial cell conditioned medium (CM) supporting retinal pigment epithelium (RPE) cell survival on aged and age-related macular degeneration (AMD) Bruch's membrane. Methods CM was subject to size separation using centrifugal filters. Retentate and filtrate fractions were tested for bioactivity by analyzing RPE survival on submacular Bruch's membrane of aged and AMD donor eyes and behavior on collagen I-coated tissue culture wells. Protein and peptide composition of active fractions was determined by mass spectrometry. Results Two bioactive fractions, 3-kDa filtrate and a 10-50–kDa fraction, were necessary for RPE survival on aged and AMD Bruch's membrane. The 3-kDa filtrate, but not the 10-50–kDa fraction, supported RPE growth on collagen 1‐coated tissue culture plates. Mass spectrometry of the 10-50–kDa fraction identified 175 extracellular proteins, including growth factors and extracellular matrix molecules. Transforming growth factor (TGF)β-2 was identified as unique to active CM. Peptides representing 29 unique proteins were identified in the 3-KDa filtrate. Conclusions These results indicate there is a minimum of two bioactive molecules in CM, one found in the 3-kDa filtrate and one in the 10-50–kDa fraction, and that bioactive molecules in both fractions must be present to ensure RPE survival on Bruch's membrane. Mass spectrometry analysis suggested proteins to test in future studies to identify proteins that may contribute to CM bioactivity. Translational Relevance Results of this study are the first steps in development of an adjunct to cell-based therapy to ensure cell transplant survival and functionality in AMD patients. PMID:26933521

Electro-activation of sweet defatted whey: Impact on the induced Maillard reaction products and bioactive peptides.

PubMed

Kareb, Ourdia; Gomaa, Ahmed; Champagne, Claude P; Jean, Julie; Aïder, Mohammed

2017-04-15

Electro-activation was used to add value to sweet defatted whey. This study aimed to investigate and to characterize the bioactive compounds formed under different electro-activation conditions by molecular and proteomic approaches. The effects of electric current intensity (400, 500 or 600mA) and whey concentration (7, 14 or 21% (w/v)) as a function of the electro-activation time (0, 15, 30 or 45min) were evaluated. The targeted dependent variables were the formation of Maillard reaction products (MRPs), protein hydrolysates and glycated compounds. It was shown that the MRPs derived from electro-activated whey at a concentration of 14% had the highest potential of biological activity. SDS-PAGE analyses indicated the formation of hydrolysates and glycated compounds with different molecular weight distributions. FTIR indicated the predominance of intermediate MRPs, such as the Schiff base compounds. LC-MS/MS and proteomics analysis showed the production of multi-functional bioactive peptides due to the hydrolysis of whey proteins. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Development of hyaluronic acid-Fe2O3 hybrid magnetic nanoparticles for targeted delivery of peptides.

PubMed

Kumar, Arun; Sahoo, Bishwabhusan; Montpetit, Alison; Behera, Sumita; Lockey, Richard F; Mohapatra, Shyam S

2007-06-01

Novel hybrid nanoparticles comprised of hyaluronic acid (HA) and iron oxide were synthesized and characterized for the first time with the average diameter of less than 160 nm. The iron oxide (Fe2O3) particles are hybridized between HA layers by electrostatic interactions between the positive surface charge of the Fe2O3 nanoparticles and the negative charge of the carboxylate groups of HA, forming a corral-like structure. The particles were also characterized by FTIR and NMR to verify the hybridization. The particles were tested for their ability to deliver peptides to the cells using HEK293 and A549 cells. Results show that these particles delivered peptides at about 100% level. These HA-iron oxide nanoparticles are expected to be useful in developing effective tissue and cell targeting systems.

Cationic Peptides and Peptidomimetics Bind Glycosaminoglycans as Potential Sema3A Pathway Inhibitors

PubMed Central

Corredor, Miriam; Bonet, Roman; Moure, Alejandra; Domingo, Cecilia; Bujons, Jordi; Alfonso, Ignacio; Pérez, Yolanda; Messeguer, Àngel

2016-01-01

Semaphorin3A (Sema3A) is a vertebrate-secreted protein that was initially characterized as a repulsive-guidance cue. Semaphorins have crucial roles in several diseases; therefore, the development of Sema3A inhibitors is of therapeutic interest. Sema3A interacts with glycosaminoglycans (GAGs), presumably through its C-terminal basic region. We used different biophysical techniques (i.e., NMR, surface plasmon resonance, isothermal titration calorimetry, fluorescence, and UV-visible spectroscopy) to characterize the binding of two Sema3A C-terminus-derived basic peptides (FS2 and NFS3) to heparin and chondroitin sulfate A. We found that these peptides bind to both GAGs with affinities in the low-micromolar range. On the other hand, a peptoid named SICHI (semaphorin-induced chemorepulsion inhibitor), which is positively charged at physiological pH, was first identified by our group as being able to block Sema3A chemorepulsion and growth-cone collapse in axons at the extracellular level. To elucidate the direct target for the reported SICHI inhibitory effect in the Sema3A signaling pathway, we looked first to the protein-protein interaction between secreted Sema3A and the Nrp1 receptor. However, our results show that SICHI does not bind directly to the Sema3A sema domain or to Nrp1 extracellular domains. We evaluated a new, to our knowledge, hypothesis, according to which SICHI binds to GAGs, thereby perturbing the Sema3A-GAG interaction. By using the above-mentioned techniques, we observed that SICHI binds to GAGs and competes with Sema3A C-terminus-derived basic peptides for binding to GAGs. These data support the ability of SICHI to block the biologically relevant interaction between Sema3A and GAGs, thus revealing SICHI as a new, to our knowledge, class of inhibitors that target the GAG-protein interaction. PMID:27028639

Actiflagelin, a new sperm activator isolated from Walterinnesia aegyptia venom using phenotypic screening.

PubMed

Abd El-Aziz, Tarek Mohamed; Al Khoury, Sawsan; Jaquillard, Lucie; Triquigneaux, Mathilde; Martinez, Guillaume; Bourgoin-Voillard, Sandrine; Sève, Michel; Arnoult, Christophe; Beroud, Rémy; De Waard, Michel

2018-01-01

Sperm contains a wealth of cell surface receptors and ion channels that are required for most of its basic functions such as motility and acrosome reaction. Conversely, animal venoms are enriched in bioactive compounds that primarily target those ion channels and cell surface receptors. We hypothesized, therefore, that animal venoms should be rich enough in sperm-modulating compounds for a drug discovery program. Our objective was to demonstrate this fact by using a sperm-based phenotypic screening to identify positive modulators from the venom of Walterinnesia aegyptia . Herein, as proof of concept that venoms contain interesting compounds for sperm physiology, we fractionated Walterinnesia aegyptia snake venom by RP-HPLC and screened for bioactive fractions capable of accelerating mouse sperm motility (primary screening). Next, we purified each compound from the positive fraction by cation exchange and identified the bioactive peptide by secondary screening. The peptide sequence was established by Edman sequencing of the reduced/alkylated compound combined to LC-ESI-QTOF MS/MS analyses of reduced/alkylated fragment peptides following trypsin or V8 protease digestion. Using this two-step purification protocol combined to cell phenotypic screening, we identified a new toxin of 7329.38 Da (actiflagelin) that activates sperm motility in vitro from OF1 male mice. Actiflagelin is 63 amino acids in length and contains five disulfide bridges along the proposed pattern of disulfide connectivity C 1 -C 5 , C 2 -C 3 , C 4 -C 6 , C 7 -C 8 and C 9 -C 10 . Modeling of its structure suggests that it belongs to the family of three finger toxins with a noticeable homology with bucandin, a peptide from Bungarus candidus venom. This report demonstrates the feasibility of identifying profertility compounds that may be of therapeutic potential for infertility cases where motility is an issue.

Gastro-Resistant Insulin Receptor-Binding Peptide from Momordica charantia Improved the Glucose Tolerance in Streptozotocin-Induced Diabetic Mice via Insulin Receptor Signaling Pathway.

PubMed

Lo, Hsin-Yi; Li, Chia-Cheng; Chen, Feng-Yuan; Chen, Jaw-Chyun; Hsiang, Chien-Yun; Ho, Tin-Yun

2017-10-25

Momordica charantia is a commonly used food and has been used for the management of diabetes. Our previous study has identified an insulin receptor (IR)-binding protein (mcIRBP) from Momordica charantia. Here we identified the gastro-resistant hypoglycemic bioactive peptides from protease-digested mcIRBP. By in vitro digestion and IR kinase activity assay, we found that a 9-amino-acid-residue peptide, mcIRBP-9, was a gastro-resistant peptide that enhanced IR kinase activities. mcIRBP-9 activated IR signaling transduction pathway, which resulted in the phosphorylation of IR, the translocation of glucose transporter 4, and the uptake of glucose in cells. Intraperitoneal and oral administration of mcIRBP-9 stimulated the glucose clearance by 30.91 ± 0.39% and 32.09 ± 0.38%, respectively, in streptozotocin-induced diabetic mice. Moreover, a pilot study showed that daily ingestion of mcIRBP-9 for 30 days decreased the fasting blood glucose levels and glycated hemoglobin (HbA1c) levels by 23.62 ± 6.14% and 24.06 ± 1.53%, respectively. In conclusion, mcIRBP-9 is a unique gastro-resistant bioactive peptide generated after the digestion of mcIRBP. Furthermore, oral administration of mcIRBP-9 improves both the glucose tolerance and the HbA1c levels in diabetic mice via targeting IR signaling transduction pathway.

Design of Bioactive Peptides from Naturally Occurring μ-Conotoxin Structures*

PubMed Central

Stevens, Marijke; Peigneur, Steve; Dyubankova, Natalia; Lescrinier, Eveline; Herdewijn, Piet; Tytgat, Jan

2012-01-01

To date, cone snail toxins (“conotoxins”) are of great interest in the pursuit of novel subtype-selective modulators of voltage-gated sodium channels (Navs). Navs participate in a wide range of electrophysiological processes. Consequently, their malfunctioning has been associated with numerous diseases. The development of subtype-selective modulators of Navs remains highly important in the treatment of such disorders. In current research, a series of novel, synthetic, and bioactive compounds were designed based on two naturally occurring μ-conotoxins that target Navs. The initial designed peptide contains solely 13 amino acids and was therefore named “Mini peptide.” It was derived from the μ-conotoxins KIIIA and BuIIIC. Based on this Mini peptide, 10 analogues were subsequently developed, comprising 12–16 amino acids with two disulfide bridges. Following appropriate folding and mass verification, blocking effects on Navs were investigated. The most promising compound established an IC50 of 34.1 ± 0.01 nm (R2-Midi on Nav1.2). An NMR structure of one of our most promising compounds was determined. Surprisingly, this structure does not reveal an α-helix. We prove that it is possible to design small peptides based on known pharmacophores of μ-conotoxins without losing their potency and selectivity. These data can provide crucial material for further development of conotoxin-based therapeutics. PMID:22773842

The Influence of the Polymer Amount on the Biological Properties of PCL/ZrO2 Hybrid Materials Synthesized via Sol-Gel Technique

PubMed Central

Tranquillo, Elisabetta; Illiano, Michela; Sapio, Luigi; Spina, Annamaria; Naviglio, Silvio

2017-01-01

Organic/inorganic hybrid materials are attracting considerable attention in the biomedical area. The sol-gel process provides a convenient way to produce many bioactive organic–inorganic hybrids. Among those, poly(e-caprolactone)/zirconia (PCL/ZrO2) hybrids have proved to be bioactive with no toxic materials. The aim of this study was to investigate the effects of these materials on the cellular response as a function of the PCL content, in order to evaluate their potential use in the biomedical field. For this purpose, PCL/ZrO2 hybrids containing 6, 12, 24, and 50 wt % of PCL were synthesized by the sol-gel method. The effects of their presence on the NIH-3T3 fibroblast cell line carrying out direct cell number counting, MTT, cell damage assays, flow cytometry-based analysis of cell-cycle progression, and immunoblotting experiments. The results confirm and extend the findings that PCL/ZrO2 hybrids are free from toxicity. The hybrids containing 12 and 24 wt % PCL, (more than 6 and 50 wt % ones) enhance cell proliferation when compared to pure ZrO2 by affecting cell cycle progression. The finding that the content of PCL in PCL/ZrO2 hybrids differently supports cell proliferation suggests that PCL/ZrO2 hybrids could be useful tools with different potential clinical applications. PMID:29039803

Design of Bioactive Organic-inorganic Hybrid Materials with Self-setting Ability

NASA Astrophysics Data System (ADS)

Miyazaki, T.; Machida, S.; Morita, Y.; Ishida, E.

2011-10-01

Paste-like materials with ability of self-setting are attractive for bone substitutes, since they can be injected from the small hole with minimized invasion to the patient. Although bone cements which set as apatite are clinically used, there is limitation on clinical applications due to their mechanical properties such as high brittleness and low fracture toughness. To overcome this problem, organic-inorganic hybrids based on a flexible polymer are attractive. We have obtained an idea for design of self-setting hybrids using polyion complex fabricated by ionic interaction of anionic and cationic polymers. We aimed at preparation of organic-inorganic hybrids exhibiting self-setting ability and bioactivity. The liquid component was prepared from cationic chitosan aqueous solution. The powder component was prepared by mixing various carrageenans with α-tricalcium phosphate (α-TCP). The obtained cements set within 1 day. Compressive strength showed tendency to increase with increase in α-TCP content in the powder component. The prepared cements formed the apatite in simulated body fluid within 3 days. Novel self-setting materials based on organic-inorganic hybrid can be designed utilizing ionic interaction of polysaccharide.

Bioactivity and mechanical properties of polydimethylsiloxane (PDMS)-CaO-SiO2 hybrids with different calcium contents.

PubMed

Kamitakahara, M; Kawashita, M; Miyata, N; Kokubo, T; Nakamura, T

2002-11-01

Polydimethylsiloxane (PDMS)-CaO-SiO(2) hybrids with starting compositions containing PDMS/(Si(OC(2)H(5))(4)+PDMS) weight ratio=0.30, H(2)O/Si(OC(2)H(5))(4) molar ratio=2, and Ca(NO(3))(2)/Si(OC(2)H(5))(4) molar ratios=0-0.2, were prepared by the sol-gel method. The apatite-forming ability of the hybrids increased with increasing calcium content in the Ca(NO(3))(2)/Si(OC(2)H(5))(4) molar ratio range 0-0.1. The hybrids with a Ca(NO(3))(2)/Si(OC(2)H(5))(4) molar ratio range 0.1-0.2 formed apatite on their surfaces in a simulated body fluid (SBF) within 12 h. The hybrid with a Ca(NO(3))(2)/Si(OC(2)H(5))(4) molar ratio of 0.10 showed an excellent apatite-forming ability in SBF with a low release of silicon into SBF. It also showed mechanical properties analogous to those of human cancellous bones. This hybrid is expected to be useful as a new type of bioactive material.

Yeast Two-Hybrid: State of the Art

PubMed Central

Beyaert, Rudi

1999-01-01

Genome projects are approaching completion and are saturating sequence databases. This paper discusses the role of the two-hybrid system as a generator of hypotheses. Apart from this rather exhaustive, financially and labour intensive procedure, more refined functional studies can be undertaken. Indeed, by making hybrids of two-hybrid systems, customised approaches can be developed in order to attack specific function-related problems. For example, one could set-up a "differential" screen by combining a forward and a reverse approach in a three-hybrid set-up. Another very interesting project is the use of peptide libraries in two-hybrid approaches. This could enable the identification of peptides with very high specificity comparable to "real" antibodies. With the technology available, the only limitation is imagination. PMID:12734586

Coupling of carbon and peptide nanotubes.

PubMed

Montenegro, Javier; Vázquez-Vázquez, Carlos; Kalinin, Arseny; Geckeler, Kurt E; Granja, Juan R

2014-02-12

Two of the main types of nanotubular architectures are the single-walled carbon nanotubes (SWCNTs) and the self-assembling cyclic peptide nanotubes (SCPNs). We here report the preparation of the dual composite resulting from the ordered combination of both tubular motifs. In the resulting architecture, the SWCNTs can act as templates for the assembly of SCPNs that engage the carbon nanotubes noncovalently via pyrene "paddles", each member of the resulting hybrid stabilizing the other in aqueous solution. The particular hybrids obtained in the present study formed highly ordered oriented arrays and display complementary properties such as electrical conductivity. Furthermore, a self-sorting of the cyclic peptides toward semiconducting rather than metallic SWCNTs is also observed in the aqueous dispersions. It is envisaged that a broad range of exploitable properties may be achieved and/or controlled by varying the cyclic peptide components of similar SWCNT/SCPN hybrids.

Recombinant fibronectin fragment III8-10/polylactic acid hybrid nanofibers enhance the bioactivity of titanium surface.

PubMed

Guillem-Marti, Jordi; Boix-Lemonche, Gerard; Gugutkov, Dencho; Ginebra, Maria-Pau; Altankov, George; Manero, Jose M

2018-04-01

To develop a nanofiber (NF)-based biomimetic coating on titanium (Ti) that mimics the complex spatiotemporal organization of the extracellular matrix (ECM). Recombinant cell attachment site (CAS) of fibronectin type III8-10 domain was co-electrospun with polylactic acid (PLA) and covalently bound on polished Ti discs. Osteoblast-like SaOS-2 cells were used to evaluate their complex bioactivity. A significant increase of cell spreading was found on CAS/PLA hybrid NFs, followed by control pure PLA NFs and bare Ti discs. Cell proliferation showed similar trend being about twice higher on CAS/PLA NFs. The significantly increased ALP activity at day 21 indicated an enhanced differentiation of SaOS-2 cells. Coating of Ti implants with hybrid CAS/PLA NFs may improve significantly their osseointegration potential.

Phage selection of peptide "microantibodies".

PubMed

Fujiwara, Daisuke; Fujii, Ikuo

2013-01-01

A bioactive peptide capable of inhibiting protein-protein interactions has the potential to be a molecular tool for biological studies and a therapeutic by disrupting aberrant interactions involved in diseases. We have developed combinatorial libraries of peptides with helix-loop-helix structure, from which the isolated peptides have the constrained structure to reduce entropy costs in binding, resulting in high binding affinities for target molecules. Previously, we designed a de novo peptide of helix-loop-helix structure that we termed a "microantibody." Using the microantibody as a library scaffold, we have constructed a phage-display library to successfully isolate molecular-targeting peptides against a cytokine receptor (granulocyte colony-stimulating factor receptor), a protein kinase (Aurora-A), and a ganglioside (GM1). Protocols in this article describe a general procedure for the library construction and the library screening.

Improved antimicrobial activities of synthetic-hybrid bacteriocins designed from enterocin E50-52 and pediocin PA-1.

PubMed

Tiwari, Santosh Kumar; Sutyak Noll, Katia; Cavera, Veronica L; Chikindas, Michael L

2015-03-01

Two hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64- and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8- and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wild-type (WT) bacteriocins on the transmembrane electrical potential (ΔΨ) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ΔΨ, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such as Micrococcus luteus, Salmonella enterica serovar Enteritidis 20E1090, and Escherichia coli O157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Improved Antimicrobial Activities of Synthetic-Hybrid Bacteriocins Designed from Enterocin E50-52 and Pediocin PA-1

PubMed Central

Tiwari, Santosh Kumar; Sutyak Noll, Katia; Cavera, Veronica L.

2014-01-01

Two hybrid bacteriocins, enterocin E50-52/pediocin PA-1 (EP) and pediocin PA-1/enterocin E50-52 (PE), were designed by combining the N terminus of enterocin E50-52 and the C terminus of pediocin PA-1 and by combining the C terminus of pediocin PA-1 and the N terminus of enterocin E50-52, respectively. Both hybrid bacteriocins showed reduced MICs compared to those of their natural counterparts. The MICs of hybrid PE and EP were 64- and 32-fold lower, respectively, than the MIC of pediocin PA-1 and 8- and 4-fold lower, respectively, than the MIC of enterocin E50-52. In this study, the effect of hybrid as well as wild-type (WT) bacteriocins on the transmembrane electrical potential (ΔΨ) and their ability to induce the efflux of intracellular ATP were investigated. Enterocin E50-52, pediocin PA-1, and hybrid bacteriocin PE were able to dissipate ΔΨ, but EP was unable to deplete this component. Both hybrid bacteriocins caused a loss of the intracellular concentration of ATP. EP, however, caused a faster efflux than PE and enterocin E50-52. Enterocin E50-52 and hybrids PE and EP were active against the Gram-positive and Gram-negative bacteria tested, such as Micrococcus luteus, Salmonella enterica serovar Enteritidis 20E1090, and Escherichia coli O157:H7. The hybrid bacteriocins designed and described herein are antimicrobial peptides with MICs lower those of their natural counterparts. Both hybrid peptides induce the loss of intracellular ATP and are capable of inhibiting Gram-negative bacteria, and PE dissipates the electrical potential. In this study, the MIC of hybrid bacteriocin PE decreased 64-fold compared to the MIC of its natural peptide counterpart, pediocin PA-1. Inhibition of Gram-negative pathogens confers an additional advantage for the application of these peptides in therapeutics. PMID:25527560

Computer aided identification of a Hevein-like antimicrobial peptide of bell pepper leaves for biotechnological use.

PubMed

Games, Patrícia Dias; daSilva, Elói Quintas Gonçalves; Barbosa, Meire de Oliveira; Almeida-Souza, Hebréia Oliveira; Fontes, Patrícia Pereira; deMagalhães, Marcos Jorge; Pereira, Paulo Roberto Gomes; Prates, Maura Vianna; Franco, Gloria Regina; Faria-Campos, Alessandra; Campos, Sérgio Vale Aguiar; Baracat-Pereira, Maria Cristina

2016-12-15

Antimicrobial peptides from plants present mechanisms of action that are different from those of conventional defense agents. They are under-explored but have a potential as commercial antimicrobials. Bell pepper leaves ('Magali R') are discarded after harvesting the fruit and are sources of bioactive peptides. This work reports the isolation by peptidomics tools, and the identification and partially characterization by computational tools of an antimicrobial peptide from bell pepper leaves, and evidences the usefulness of records and the in silico analysis for the study of plant peptides aiming biotechnological uses. Aqueous extracts from leaves were enriched in peptide by salt fractionation and ultrafiltration. An antimicrobial peptide was isolated by tandem chromatographic procedures. Mass spectrometry, automated peptide sequencing and bioinformatics tools were used alternately for identification and partial characterization of the Hevein-like peptide, named HEV-CANN. The computational tools that assisted to the identification of the peptide included BlastP, PSI-Blast, ClustalOmega, PeptideCutter, and ProtParam; conventional protein databases (DB) as Mascot, Protein-DB, GenBank-DB, RefSeq, Swiss-Prot, and UniProtKB; specific for peptides DB as Amper, APD2, CAMP, LAMPs, and PhytAMP; other tools included in ExPASy for Proteomics; The Bioactive Peptide Databases, and The Pepper Genome Database. The HEV-CANN sequence presented 40 amino acid residues, 4258.8 Da, theoretical pI-value of 8.78, and four disulfide bonds. It was stable, and it has inhibited the growth of phytopathogenic bacteria and a fungus. HEV-CANN presented a chitin-binding domain in their sequence. There was a high identity and a positive alignment of HEV-CANN sequence in various databases, but there was not a complete identity, suggesting that HEV-CANN may be produced by ribosomal synthesis, which is in accordance with its constitutive nature. Computational tools for proteomics and databases are not adjusted for short sequences, which hampered HEV-CANN identification. The adjustment of statistical tests in large databases for proteins is an alternative to promote the significant identification of peptides. The development of specific DB for plant antimicrobial peptides, with information about peptide sequences, functional genomic data, structural motifs and domains of molecules, functional domains, and peptide-biomolecule interactions are valuable and necessary.

Guanidino groups greatly enhance the action of antimicrobial peptidomimetics against bacterial cytoplasmic membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreev, Konstantin; Bianchi, Christopher; Laursen, Jonas S.

Antimicrobial peptides or their synthetic mimics are a promising class of potential new antibiotics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanismof antimicrobial α-peptide–β-peptoid chimeras. Langmuirmonolayers composed of 1,2-dipalmitoylsn- glycero-3-phosphatidylglycerol (DPPG) were used to model cytoplasmic membranes of both Gram-positive and Gram-negative bacteria,while lipopolysaccharide Kdo2-lipid Amonolayersweremimicking the outer membrane of Gram-negative species.We report the results of themeasurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity to study the molecularmechanisms of peptidomimetic interaction with bacterialmembranes.We found guanidinomore » group-containing chimeras to exhibit greater disruptive activity on DPPGmonolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharidemonolayerswhere the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies.« less

Guanidino Groups Greatly Enhance the Action of Antimicrobial Peptidomimetics Against Bacterial Cytoplasmic Membranes

PubMed Central

Laursen, Jonas S.; Citterio, Linda; Hein-Kristensen, Line; Gram, Lone; Kuzmenko, Ivan; Olsen, Christian A.; Gidalevitz, David

2014-01-01

A promising class of potential new antibiotics are the antimicrobial peptides or their synthetic mimics. Herein we assess the effect of the type of cationic side chain (i.e., guanidino vs. amino groups) on the membrane perturbing mechanism of antimicrobial α-peptide–β-peptoid chimeras. Two separate Langmuir monolayers composed of 1,2-dipalmitoyl-sn-glycero-3-phosphatidylglycerol (DPPG) and lipopolysaccharide Kdo2-lipid A were applied to model the outer membranes of Gram-positive and Gram-negative bacteria, respectively. We report the results of the measurements using an array of techniques, including high-resolution synchrotron surface X-ray scattering, epifluorescence microscopy, and in vitro antimicrobial activity to study the molecular mechanisms of peptidomimetic interaction with bacterial membranes. We found guanidino group-containing chimeras to exhibit greater disruptive activity on DPPG monolayers than the amino group-containing analogues. However, this effect was not observed for lipopolysaccharide monolayers where the difference was negligible. Furthermore, the addition of the nitrobenzoxadiazole fluorophore did not reduce the insertion activity of these antimicrobials into both model membrane systems examined, which may be useful for future cellular localization studies. PMID:24878450

Dicarboxylic esters: Useful tools for the biocatalyzed synthesis of hybrid compounds and polymers

PubMed Central

Bassanini, Ivan; Hult, Karl

2015-01-01

Summary Dicarboxylic acids and their derivatives (esters and anhydrides) have been used as acylating agents in lipase-catalyzed reactions in organic solvents. The synthetic outcomes have been dimeric or hybrid derivatives of bioactive natural compounds as well as functionalized polyesters. PMID:26664578

TEMPO-Assisted Free Radical-Initiated Peptide Sequencing Mass Spectrometry (FRIPS MS) in Q-TOF and Orbitrap Mass Spectrometers: Single-Step Peptide Backbone Dissociations in Positive Ion Mode

NASA Astrophysics Data System (ADS)

Jang, Inae; Lee, Sun Young; Hwangbo, Song; Kang, Dukjin; Lee, Hookeun; Kim, Hugh I.; Moon, Bongjin; Oh, Han Bin

2017-01-01

The present study demonstrates that one-step peptide backbone fragmentations can be achieved using the TEMPO [2-(2,2,6,6-tetramethyl piperidine-1-oxyl)]-assisted free radical-initiated peptide sequencing (FRIPS) mass spectrometry in a hybrid quadrupole time-of-flight (Q-TOF) mass spectrometer and a Q-Exactive Orbitrap instrument in positive ion mode, in contrast to two-step peptide fragmentation in an ion-trap mass spectrometer (reference Anal. Chem. 85, 7044-7051 (30)). In the hybrid Q-TOF and Q-Exactive instruments, higher collisional energies can be applied to the target peptides, compared with the low collisional energies applied by the ion-trap instrument. The higher energy deposition and the additional multiple collisions in the collision cell in both instruments appear to result in one-step peptide backbone dissociations in positive ion mode. This new finding clearly demonstrates that the TEMPO-assisted FRIPS approach is a very useful tool in peptide mass spectrometry research.

Fabricated Elastin.

PubMed

Yeo, Giselle C; Aghaei-Ghareh-Bolagh, Behnaz; Brackenreg, Edwin P; Hiob, Matti A; Lee, Pearl; Weiss, Anthony S

2015-11-18

The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows the precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides, and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge, and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone, and dental replacement. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabricated elastin

PubMed Central

Yeo, Giselle C.; Weiss, Anthony S.

2015-01-01

The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows for precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone and dental replacement. PMID:25771993

Preparation, characterization and in vitro evaluation of ε-polylysine-loaded polymer blend microparticles for potential pancreatic cancer therapy.

PubMed

Chevalier, Merari T; García, Mónica C; Gonzalez, Daniela; Gomes-Filho, Sandro M; Bassères, Daniela S; Farina, Hernan; Alvarez, Vera A

2017-09-01

Peptide active ingredients show great promise regarding the treatment of various health-endangering diseases. It is reported that L-lysine inhibits the proliferation of several tumour lines in vitro and in vivo. However, proteins and peptide drugs possess certain disadvantages such as in vivo instability and short biological half-life. On the grounds that drug delivery systems can overcome a wide spectrum of bioactive compounds issues, a biopolymeric blend-based microparticulated system capable of delivering ε-polylysine (PLL) was developed. PLL-loaded poly((L)Lactic acid)/poly(D,L-Lactide)-co-poly(ethylene glycol)-based microparticles (PLL-PB-MPs) were prepared and fully characterised exhibiting a narrow size distribution (1.2 ± 0.12 µm), high loading efficiency (81%) and improved thermal stability (T d from 250 °C to 291 °C). The cytotoxicity and antiproliferative effect of PLL-PB-MPs in pancreatic adenocarcinoma cell lines BxPC3 and MIA PaCa-2 were confirmed. Due to their physicochemical and biopharmaceutical properties, PB-MPs constitute a promising carrier to deliver bioactive peptides.

Combined genetic and bioactivity-based prioritization leads to the isolation of an endophyte-derived antimycobacterial compound.

PubMed

Alvin, A; Kalaitzis, J A; Sasia, B; Neilan, B A

2016-05-01

To initiate a genetic and bioactivity-based screening programme of culturable endophytes to identify micro-organisms capable of producing bioactive polyketides and peptides. Fungal endophytes were isolated from flowers, leaves and roots of Rhoeo spathacea, revealing a community consisting of Colletotrichum sp., Fusarium sp., Guignardia sp., Phomopsis sp., Phoma sp. and Microdochium sp. Genetic screening showed that all isolates had polyketide synthase (PKS) genes and most had nonribosomal peptide synthetase (NRPS) genes. Ethyl acetate extracts of the fungal isolates exhibited antiproliferative activity against at least one of the seven bacterial and mycobacterial test strains. Nuclear Magnetic Resonance -guided fractionation of the crude extract from a Fusarium sp. strain which exhibited strong antiproliferative activity against Mycobacterium tuberculosis resulted in the isolation of the polyketide javanicin. This compound was active against Myco. tuberculosis (MIC = 25 μg ml(-1)) and Mycobacterium phlei (MIC = 50 μg ml(-1)). The medicinal plant R. spathacea hosts a variety of fungal endophytes capable of producing antibacterial and antimycobacterial compounds. There is a positive correlation between the presence of PKS and/or NRPS encoding genes in endophytes and the bioactivity of their respective organic extracts. This is the first report on the fungal endophytic diversity of R. spathacea, and the isolation of an antimycobacterial compound from the plant which has been traditionally used for the treatment of tuberculosis symptoms. © 2016 The Society for Applied Microbiology.

Invited review: Fermented milk as antihypertensive functional food.

PubMed

Beltrán-Barrientos, L M; Hernández-Mendoza, A; Torres-Llanez, M J; González-Córdova, A F; Vallejo-Córdoba, B

2016-06-01

Over the past decade, interest has risen in fermented dairy foods that promote health and could prevent diseases such as hypertension. This biological effect has mainly been attributed to bioactive peptides encrypted within dairy proteins that can be released during fermentation with specific lactic acid bacteria or during gastrointestinal digestion. The most studied bioactive peptides derived from dairy proteins are antihypertensive peptides; however, a need exists to review the different studies dealing with the evaluation of antihypertensive fermented milk before a health claim may be associated with the product. Thus, the objective of this overview was to present available information related to the evaluation of fermented milk containing antihypertensive peptides by in vitro and in vivo studies, which are required before a fermented functional dairy product may be introduced to the market. Although commercial fermented milks with antihypertensive effects exist, these are scarce and most are based on Lactobacillus helveticus. Thus, a great opportunity is available for the development of functional dairy products with new lactic acid bacteria that support heart health through blood pressure- and heart rate-lowering effects. Hence, the consumer may be willing to pay a premium for foods with important functional benefits. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Strategies for the construction and use of peptide and antibody libraries displayed on phages.

PubMed

Pini, Alessandro; Giuliani, Andrea; Ricci, Claudia; Runci, Ylenia; Bracci, Luisa

2004-12-01

Combinatorial chemistry and biology have become popular methods for the identification of bio-active molecules in drug discovery. A widely used technique in combinatorial biology is "phage display", by which peptides, antibody fragments and enzymes are displayed on the surface of bacteriophages, and can be selected by simple procedures of biopanning. The construction of phage libraries of peptides or antibody fragments provides a huge source of ligands and bio-active molecules that can be isolated from the library without laborious studies on antigen characteristics and prediction of ligand structure. This "irrational" approach for the construction of new drugs is extremely rapid and is now used by thousands of laboratories world-wide. The bottleneck in this procedure is the availability of large reliable libraries that can be used repeatedly over the years without loss of ligand expression and diversity. Construction of personalized libraries is therefore important for public and private laboratories engaged in the isolation of specific molecules for therapeutic or diagnostic use. Here we report the general strategies for constructing large phage peptide and antibody libraries, based on the experience of researchers who built the world's most widely used libraries. Particular attention is paid to advanced strategies for the construction, preservation and panning.

Functionalization of alkyne-terminated thermally hydrocarbonized porous silicon nanoparticles with targeting peptides and antifouling polymers: effect on the human plasma protein adsorption.

PubMed

Wang, Chang-Fang; Mäkilä, Ermei M; Bonduelle, Colin; Rytkönen, Jussi; Raula, Janne; Almeida, Sérgio; Närvänen, Ale; Salonen, Jarno J; Lecommandoux, Sebastien; Hirvonen, Jouni T; Santos, Hélder A

2015-01-28

Porous silicon (PSi) nanomaterials combine a high drug loading capacity and tunable surface chemistry with various surface modifications to meet the requirements for biomedical applications. In this work, alkyne-terminated thermally hydrocarbonized porous silicon (THCPSi) nanoparticles were fabricated and postmodified using five bioactive molecules (targeting peptides and antifouling polymers) via a single-step click chemistry to modulate the bioactivity of the THCPSi nanoparticles, such as enhancing the cellular uptake and reducing the plasma protein association. The size of the nanoparticles after modification was increased from 176 to 180-220 nm. Dextran 40 kDa modified THCPSi nanoparticles showed the highest stability in aqueous buffer. Both peptide- and polymer-functionalized THCPSi nanoparticles showed an extensive cellular uptake which was dependent on the functionalized moieties presented on the surface of the nanoparticles. The plasma protein adsorption study showed that the surface modification with different peptides or polymers induced different protein association profiles. Dextran 40 kDa functionalized THCPSi nanoparticles presented the least protein association. Overall, these results demonstrate that the "click" conjugation of the biomolecules onto the alkyne-terminated THCPSi nanoparticles is a versatile and simple approach to modulate the surface chemistry, which has high potential for biomedical applications.

An Extensive Description of the Peptidomic Repertoire of the Hen Egg Yolk Plasma.

PubMed

Arena, Simona; Scaloni, Andrea

2018-03-28

Hen egg is a raw material widely used for the preparation of food,  pharmaceutical and cosmetoceutical products. Dedicated proteomic studies were accomplished on eggshell membrane, egg white, and yolk, identifying the most abundant proteins. No similar peptidomic studies have been performed so far. Only preliminary investigations on bioactive peptides in egg fractions and digestates were accomplished through functional screening assays, characterizing antioxidant, antibacterial, antiviral, immunomodulatory, and antihypertensive preparations and isolated components. This study fills this gap and provides a comprehensive picture of the peptides present in the yolk plasma of different hen egg types after 24 and 264 h of laying, taking advantage of a procedure based on a two-step fractionation followed by combined MALDI-TOF-TOF-MS- and nanoLC-ESI-Q-Orbitrap-MS/MS-based analysis. Six hundred and twenty-eight peptides were characterized as deriving from the proteolytic processing of larger protein components after the physiological action of chicken chymotrypsin-like and pepsin-like enzymes. Structural details on their post-translational modifications were also provided. Identified peptides were subjected to bioinformatic analysis and further compared with available data from the literature, ascertaining 198 peptides associable with putative antihypertensive, antimicrobial, anticancer, antiviral, antibiofilm, anorectic, calcium-binding, and anti-inflammatory activities. This analysis was often confirmative of previous experimental evidence on functional properties of unfractionated preparations or isolated molecules. These results further emphasize the bioactive action of yolk-derived peptides as related to egg consumption, and the potential use of these molecules as additive ingredients in the preparation of functional foods and cosmetics.

Discovery of native autoantigens via antigen surrogate technology: application to type 1 diabetes.

PubMed

Doran, Todd M; Simanski, Scott; Kodadek, Thomas

2015-02-20

A fundamental goal in understanding the mechanisms of autoimmune disease is the characterization of autoantigens that are targeted by autoreactive antibodies and T cells. Unfortunately, the identification of autoantigens is a difficult problem. We have begun to explore a novel route to the discovery of autoantibody/autoantigen pairs that involves comparative screening of combinatorial libraries of unnatural, synthetic molecules for compounds that bind antibodies present at much higher levels in the serum of individuals with a given autoimmune disease than in the serum of control individuals. We have shown that this approach can yield "antigen surrogates" capable of capturing disease-specific autoantibodies from serum. In this report, we demonstrate that the synthetic antigen surrogates can be used to affinity purify the autoantibodies from serum and that these antibodies can then be used to identify their cognate autoantigen in an appropriate tissue lysate. Specifically, we report the discovery of a peptoid able to bind autoantibodies present in about one-third of nonobese diabetic (NOD) mice. The peptoid-binding autoantibodies were highly enriched through peptoid affinity chromatography and employed to probe mouse pancreatic and brain lysates. This resulted in identification of murine GAD65 as the native autoantigen. GAD65 is a known humoral autoantigen in human type 1 diabetes mellitus (T1DM), but its existence in mice had been controversial. This study demonstrates the potential of this chemical approach for the unbiased identification of autoantigen/autoantibody complexes.

Access to site-specific Fc-cRGD peptide conjugates through streamlined expressed protein ligation.

PubMed

Frutos, S; Jordan, J B; Bio, M M; Muir, T W; Thiel, O R; Vila-Perelló, M

2016-10-12

An ideal drug should be highly effective, non-toxic and be delivered by a convenient and painless single dose. We are still far from such optimal treatment but peptides, with their high target selectivity and low toxicity profiles, provide a very attractive platform from which to strive towards it. One of the major limitations of peptide drugs is their high clearance rates, which limit dosage regimen options. Conjugation to antibody Fc domains is a viable strategy to improve peptide stability by increasing their hydrodynamic radius and hijacking the Fc recycling pathway. We report the use of a split-intein based semi-synthetic approach to site-specifically conjugate a synthetic integrin binding peptide to an Fc domain. The strategy described here allows conjugating synthetic peptides to Fc domains, which is not possible via genetic methods, fully maintaining the ability of both the Fc domain and the bioactive peptide to interact with their binding partners.

New insights into the bioactivity of peptides from probiotics.

PubMed

Mandal, Santi M; Pati, Bikas R; Chakraborty, Ranadhir; Franco, Octavio L

2016-06-01

Probiotics are unique bacteria that offer several therapeutic benefits to human beings when administered in optimum amounts. Probiotics are able to produce antimicrobial substances, which stimulate the body's immune responses. Here, we review in detail the anti-infective peptides derived from probiotics and their potential immunomodulatory and anti-inflammatory activities, including a major role in cross-talk between probiotics and gut microbiota under adverse conditions. Insights from the engineered cell surface of probiotics may provide novel anti-infective therapy by heterologous expression of receptor peptides of bacterial toxins. It may be possible to use antigenic peptides from viral pathogens as live vaccines. Another possibility is to generate antiviral peptides that bind directly to virus particles, while some peptides exert anti-inflammatory and anticancer effects. Some extracellular polymeric substances might serve as anti-infective peptides. These avenues of treatment have remained largely unexplored to date, despite their potential in generating powerful anti-inflammatory and anti-infective products.

Angiotensin-I-Converting Enzyme (ACE)-Inhibitory Peptides from Plants

PubMed Central

Daskaya-Dikmen, Ceren; Yucetepe, Aysun; Karbancioglu-Guler, Funda; Daskaya, Hayrettin; Ozcelik, Beraat

2017-01-01

Hypertension is an important factor in cardiovascular diseases. Angiotensin-I-converting enzyme (ACE) inhibitors like synthetic drugs are widely used to control hypertension. ACE-inhibitory peptides from food origins could be a good alternative to synthetic drugs. A number of plant-based peptides have been investigated for their potential ACE inhibitor activities by using in vitro and in vivo assays. These plant-based peptides can be obtained by solvent extraction, enzymatic hydrolysis with or without novel food processing methods, and fermentation. ACE-inhibitory activities of peptides can be affected by their structural characteristics such as chain length, composition and sequence. ACE-inhibitory peptides should have gastrointestinal stability and reach the cardiovascular system to show their bioactivity. This paper reviews the current literature on plant-derived ACE-inhibitory peptides including their sources, production and structure, as well as their activity by in vitro and in vivo studies and their bioavailability. PMID:28333109

Crack-free polydimethylsiloxane-bioactive glass-poly(ethylene glycol) hybrid monoliths with controlled biomineralization activity and mechanical property for bone tissue regeneration.

PubMed

Chen, Jing; Du, Yuzhang; Que, Wenxiu; Xing, Yonglei; Chen, Xiaofeng; Lei, Bo

2015-12-01

Crack-free organic-inorganic hybrid monoliths with controlled biomineralization activity and mechanical property have an important role for highly efficient bone tissue regeneration. Here, biomimetic and crack-free polydimethylsiloxane (PDMS)-modified bioactive glass (BG)-poly(ethylene glycol) (PEG) (PDMS-BG-PEG) hybrids monoliths were prepared by a facile sol-gel technique. Results indicate that under the assist of co-solvents, BG sol and PDMS and PEG could be hybridized at a molecular level, and effects of the PEG molecular weight on the structure, biomineralization activity, and mechanical property of the as-prepared hybrid monoliths were also investigated in detail. It is found that an addition of low molecular weight PEG can significantly prevent the formation of cracks and speed up the gelation of the hybrid monoliths, and the surface microstructure of the hybrid monoliths can be changed from the porous to the smooth as the PEG molecular weight increases. Additionally, the hybrid monoliths with low molecular weight PEG show the high formation of the biological apatite layer, while the hybrids with high molecular weight PEG exhibit negligible biomineralization ability in simulated body fluid (SBF). Furthermore, the PDMS-BG-PEG 600 hybrid monolith has significantly high compressive strength (32 ± 3 MPa) and modulus (153 ± 11 MPa), as well as good cell biocompatibility by supporting osteoblast (MC3T3-E1) attachment and proliferation. These results indicate that the as-prepared PDMS-BG-PEG hybrid monoliths may have promising applications for bone tissue regeneration. Copyright © 2015 Elsevier B.V. All rights reserved.

Use of Lantibiotic Synthetases for the Preparation of Bioactive Constrained Peptides

PubMed Central

Levengood, Matthew R.

2008-01-01

Stabilization of biologically active peptides is a major goal in peptide-based drug design. Cyclization is an often-used strategy to enhance resistance of peptides towards protease degradation and simultaneously improve their affinity for targets by restricting their conformational flexibility. Amongst the various cyclization strategies, the use of thioether crosslinks has been successful for various peptides including enkephalin. The synthesis of these thioethers can be arduous, especially for longer peptides. Described herein is an enzymatic strategy taking advantage of the lantibiotic synthetase LctM that dehydrates Ser and Thr residues to the corresponding dehydroalanine and dehydrobutyrine residues and catalyzes the Michael-type addition of Cys residues to form thioether crosslinks. The use of LctM to prepare thioether containing analogs of enkephalin, contryphan, and inhibitors of human tripeptidyl peptidase II and spider venom epimerase is demonstrated. PMID:18294843

Enzyme-Assisted Discovery of Antioxidant Peptides from Edible Marine Invertebrates: A Review

PubMed Central

Chai, Tsun-Thai; Law, Yew-Chye; Wong, Fai-Chu; Kim, Se-Kwon

2017-01-01

Marine invertebrates, such as oysters, mussels, clams, scallop, jellyfishes, squids, prawns, sea cucumbers and sea squirts, are consumed as foods. These edible marine invertebrates are sources of potent bioactive peptides. The last two decades have seen a surge of interest in the discovery of antioxidant peptides from edible marine invertebrates. Enzymatic hydrolysis is an efficient strategy commonly used for releasing antioxidant peptides from food proteins. A growing number of antioxidant peptide sequences have been identified from the enzymatic hydrolysates of edible marine invertebrates. Antioxidant peptides have potential applications in food, pharmaceuticals and cosmetics. In this review, we first give a brief overview of the current state of progress of antioxidant peptide research, with special attention to marine antioxidant peptides. We then focus on 22 investigations which identified 32 antioxidant peptides from enzymatic hydrolysates of edible marine invertebrates. Strategies adopted by various research groups in the purification and identification of the antioxidant peptides will be summarized. Structural characteristic of the peptide sequences in relation to their antioxidant activities will be reviewed. Potential applications of the peptide sequences and future research prospects will also be discussed. PMID:28212329

Enzyme-Assisted Discovery of Antioxidant Peptides from Edible Marine Invertebrates: A Review.

PubMed

Chai, Tsun-Thai; Law, Yew-Chye; Wong, Fai-Chu; Kim, Se-Kwon

2017-02-16

Marine invertebrates, such as oysters, mussels, clams, scallop, jellyfishes, squids, prawns, sea cucumbers and sea squirts, are consumed as foods. These edible marine invertebrates are sources of potent bioactive peptides. The last two decades have seen a surge of interest in the discovery of antioxidant peptides from edible marine invertebrates. Enzymatic hydrolysis is an efficient strategy commonly used for releasing antioxidant peptides from food proteins. A growing number of antioxidant peptide sequences have been identified from the enzymatic hydrolysates of edible marine invertebrates. Antioxidant peptides have potential applications in food, pharmaceuticals and cosmetics. In this review, we first give a brief overview of the current state of progress of antioxidant peptide research, with special attention to marine antioxidant peptides. We then focus on 22 investigations which identified 32 antioxidant peptides from enzymatic hydrolysates of edible marine invertebrates. Strategies adopted by various research groups in the purification and identification of the antioxidant peptides will be summarized. Structural characteristic of the peptide sequences in relation to their antioxidant activities will be reviewed. Potential applications of the peptide sequences and future research prospects will also be discussed.

Disulfide Bridges: Bringing Together Frustrated Structure in a Bioactive Peptide.

PubMed

Zhang, Yi; Schulten, Klaus; Gruebele, Martin; Bansal, Paramjit S; Wilson, David; Daly, Norelle L

2016-04-26

Disulfide bridges are commonly found covalent bonds that are usually believed to maintain structural stability of proteins. Here, we investigate the influence of disulfide bridges on protein dynamics through molecular dynamics simulations on the cysteine-rich trypsin inhibitor MCoTI-II with three disulfide bridges. Correlation analysis of the reduced cyclic peptide shows that two of the three disulfide distances (Cys(11)-Cys(23) and Cys(17)-Cys(29)) are anticorrelated within ∼1 μs of bridge formation or dissolution: when the peptide is in nativelike structures and one of the distances shortens to allow bond formation, the other tends to lengthen. Simulations over longer timescales, when the denatured state is less structured, do not show the anticorrelation. We propose that the native state contains structural elements that frustrate one another's folding, and that the two bridges are critical for snapping the frustrated native structure into place. In contrast, the Cys(4)-Cys(21) bridge is predicted to form together with either of the other two bridges. Indeed, experimental chromatography and nuclear magnetic resonance data show that an engineered peptide with the Cys(4)-Cys(21) bridge deleted can still fold into its near-native structure even in its noncyclic form, confirming the lesser role of the Cys(4)-Cys(21) bridge. The results highlight the importance of disulfide bridges in a small bioactive peptide to bring together frustrated structure in addition to maintaining protein structural stability. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Can Helical Peptides Unwind One Turn at a Time? - Controlled Conformational Transitions in α,β(2,3)-Hybrid Peptides.

PubMed

Balamurugan, Dhayalan; Muraleedharan, Kannoth M

2015-06-22

Unfolding of helical trans-β(2,3) -hybrid peptides with (α-β)n α composition, when executed by increasing solvent polarity or temperature, proceeded in a systematic manner with the turns unwinding sequentially; C-terminal region of these peptides were first to unwind and the process propagated towards N terminus with more and more β residues equilibrating from the gauche to the anti rotameric state across Cα-Cβ . This is evidenced by clear change in their Cβ H signal splitting, (3)JCαH-CβH values, and sequential disappearance of i,i+2 NOEs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Formation of periodic γ-turns in α/β-hybrid peptides: DFT and NMR experimental evidence.

PubMed

Chandrasekhar, Srivari; Rao, Kakita Veera Mohana; Seenaiah, Mallikanti; Naresh, Police; Devi, Ambure Sharada; Jagadeesh, Bharatam

2014-02-01

Hybrid peptidic oligomers comprising natural and unnatural amino acid residues that can exhibit biomolecular folding and hydrogen-bonding mimicry have attracted considerable interest in recent years. While a variety of hybrid peptidic helices have been reported in the literature, other secondary structural patterns such as γ-turns and ribbons have not been well explored so far. The present work reports the design of novel periodic γ-turns in the oligomers of 1:1 natural-α/unnatural trans-β-norborenene (TNAA) amino acid residues. Through DFT, NMR, and MD studies, it is convincingly shown that, in the mixed conformational pool, the heterogeneous backbone of the hybrid peptides preferentially adopt periodic 8-membered (pseudo γ-turn)/7-membered (inverse γ-turn) hydrogen bonds in both polar and non-polar solvent media. It is observed that the stereochemistry and local conformational preference of the β-amino acid building blocks have a profound influence on accessing the specific secondary fold. These findings may be of significant relevance for the development of molecular scaffolds that facilitate desired positioning of functional side-chains. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exposing Differences in Monomer Exchange Rates of Multicomponent Supramolecular Polymers in Water.

PubMed

Baker, Matthew B; Gosens, Ronald P J; Albertazzi, Lorenzo; Matsumoto, Nicholas M; Palmans, Anja R A; Meijer, E W

2016-02-02

The formation of multicomponent and bioactive supramolecular polymers is a promising strategy for the formation of biomaterials that match the dynamic and responsive nature of biological systems. In order to fully realize the potential of this strategy, knowledge of the location and behavior of bioactive components within the system is crucial. By employing synthetic strategies to create multifunctional monomers, coupled with FRET and STORM techniques, we have investigated the formation and behavior of a bioactive and multicomponent supramolecular polymer. By creating a peptide-dye-monomer conjugate, we were able to measure high degrees of monomer incorporation and to visualize the equal distribution of monomers within the supramolecular polymer. Furthermore, by tracking the movement of monomers, we uncovered small differences in the dynamics of the bioactive monomers. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential Pharmacological Resources: Natural Bioactive Compounds from Marine-Derived Fungi

PubMed Central

Jin, Liming; Quan, Chunshan; Hou, Xiyan; Fan, Shengdi

2016-01-01

In recent years, a considerable number of structurally unique metabolites with biological and pharmacological activities have been isolated from the marine-derived fungi, such as polyketides, alkaloids, peptides, lactones, terpenoids and steroids. Some of these compounds have anticancer, antibacterial, antifungal, antiviral, anti-inflammatory, antioxidant, antibiotic and cytotoxic properties. This review partially summarizes the new bioactive compounds from marine-derived fungi with classification according to the sources of fungi and their biological activities. Those fungi found from 2014 to the present are discussed. PMID:27110799

Mechanisms of Glucagon Degradation at Alkaline pH

PubMed Central

Caputo, Nicholas; Castle, Jessica R.; Bergstrom, Colin P.; Carroll, Julie M.; Bakhtiani, Parkash A.; Jackson, Melanie A.; Roberts, Charles T.; David, Larry L.; Ward, W. Kenneth

2014-01-01

Glucagon is unstable and undergoes degradation and aggregation in aqueous solution. For this reason, its use in portable pumps for closed loop management of diabetes is limited to very short periods. In this study, we sought to identify the degradation mechanisms and the bioactivity of specific degradation products. We studied degradation in the alkaline range, a range at which aggregation is minimized. Native glucagon and analogs identical to glucagon degradation products were synthesized. To quantify biological activity in glucagon and in the degradation peptides, a protein kinase A-based bioassay was used. Aged, fresh, and modified peptides were analyzed by liquid chromatography with mass spectrometry (LCMS). Oxidation of glucagon at the Met residue was common but did not reduce bioactivity. Deamidation and isomerization were also common and were more prevalent at pH 10 than 9. The biological effects of deamidation and isomerization were unpredictable; deamidation at some sites did not reduce bioactivity. Deamidation of Gln 3, isomerization of Asp 9, and deamidation with isomerization at Asn 28 all caused marked potency loss. Studies with molecular-weight-cutoff membranes and LCMS revealed much greater fibrillation at pH 9 than 10. Further work is necessary to determine formulations of glucagon that minimize degradation and fibrillation. PMID:23651991

Bioactive Components in Fish Venoms

PubMed Central

Ziegman, Rebekah; Alewood, Paul

2015-01-01

Animal venoms are widely recognized excellent resources for the discovery of novel drug leads and physiological tools. Most are comprised of a large number of components, of which the enzymes, small peptides, and proteins are studied for their important bioactivities. However, in spite of there being over 2000 venomous fish species, piscine venoms have been relatively underrepresented in the literature thus far. Most studies have explored whole or partially fractioned venom, revealing broad pharmacology, which includes cardiovascular, neuromuscular, cytotoxic, inflammatory, and nociceptive activities. Several large proteinaceous toxins, such as stonustoxin, verrucotoxin, and Sp-CTx, have been isolated from scorpaenoid fish. These form pores in cell membranes, resulting in cell death and creating a cascade of reactions that result in many, but not all, of the physiological symptoms observed from envenomation. Additionally, Natterins, a novel family of toxins possessing kininogenase activity have been found in toadfish venom. A variety of smaller protein toxins, as well as a small number of peptides, enzymes, and non-proteinaceous molecules have also been isolated from a range of fish venoms, but most remain poorly characterized. Many other bioactive fish venom components remain to be discovered and investigated. These represent an untapped treasure of potentially useful molecules. PMID:25941767

Polyoxometalate-Based Organic-Inorganic Hybrids as Antitumor Drugs.

PubMed

Fu, Lei; Gao, Hanqin; Yan, Mei; Li, Shouzhu; Li, Xinyu; Dai, Zhifei; Liu, Shaoqin

2015-06-24

Polyoxometalates (POMs) have shown encouraging antitumor activity. However, their cytotoxicity in normal cells and unspecific interactions with biomolecules are two major obstacles that impede the practical applications of POMs in clinical cancer treatment. Derivatization of POMs with more biocompatible organic ligands is expected to cause a synergetic effect and achieve improved bioactivity and biospecificity. Herein, the synthesis of an amphiphilic organic-inorganic hybrid is reported by grafting a long-chain organoalkoxysilane lipid onto a POM. The amphiphilic POM hybrid could spontaneously assemble into the vesicles and exhibits enhanced antitumor activity for human colorectal cancer cell lines (HT29) compared to that of parent POMs. This detailed study reveals that the amphiphilic nature of POM hybrids enables the as-formed vesicles to easily bind to the cell membranes and then be uptaken by the cells, thus leading to a substantial increase in antitumor activity. Such prominent antitumor action is mostly accomplished via cell apoptosis, which ultimately results in cell death. Our finding demonstrates that novel POM hybrids-based drugs with increased bioactivity could be obtained by decorating POMs with selective organic ligands. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction and preliminary chemical characterization of the venom of the spider wasp Pepsis decorata (Hymenoptera: Pompilidae).

PubMed

Nolasco, Matheus; Biondi, Ilka; Pimenta, Daniel C; Branco, Alexsandro

2018-04-26

Arthropod venoms may be considered important sources of bioactive molecules; however, technical difficulties, such as venom extraction and homogeneity may impair the biochemical identification of new molecules. In this context, we have developed a method to maintain wasps in captivity that allows the collection of the venom, without use of chemical, mechanical or electrical stimuli. The crude venom was analyzed by RP-HPLC-ESIQ-ToF and 20 peptides were identified by de novo peptide sequencing, among them Eumenine-Mastoparan and a Ponericin-G2-simile peptide. Copyright © 2018. Published by Elsevier Ltd.

Human gastrin-releasing peptide gene is located on chromosome 18.

PubMed

Naylor, S L; Sakaguchi, A Y; Spindel, E; Chin, W W

1987-01-01

Gastrin-releasing peptide (GRP), a bombesin-like peptide, increases plasma levels of gastrin, pancreatic polypeptide, glucagon, gastric inhibitory peptide, and insulin. GRP is produced in large quantities by small-cell lung cancer and acts as a growth factor for these cells. To determine if chromosomal changes in small-cell lung cancer are related to the expression of GRP, we chromosomally mapped the gene using human-mouse somatic cell hybrids. Twenty hybrids, characterized for human chromosomes, were analyzed by Southern filter hybridization of DNA digested with EcoRI. Human DNA cut with EcoRI yields a major band of 6.8 kb and a minor band of 11.3 kb. The 6.8 kb band segregated concordantly with chromosome 18 and the marker peptidase A. The chromosome 3 abnormalities seen in small-cell lung cancer do not correlate with the chromosomal location of GRP, suggesting that the elevated expression of this gene may be due to mechanisms other than chromosomal rearrangement.

C9/12 Ribbon-Like Structures in Hybrid Peptides Alternating α- and Thiazole-Based γ-Amino Acids.

PubMed

Bonnel, Clément; Legrand, Baptiste; Simon, Matthieu; Martinez, Jean; Bantignies, Jean-Louis; Kang, Young Kee; Wenger, Emmanuel; Hoh, Francois; Masurier, Nicolas; Maillard, Ludovic T

2017-12-11

According to their restricted conformational freedom, heterocyclic γ-amino acids are usually considered to be related to Z-vinylogous γ-amino acids. In this context, oligomers alternating α-amino acids and thiazole-based γ-amino acids (ATCs) were expected to fold into a canonical 12-helical shape as described for α/γ-hybrid peptides composed of cis-α/β-unsaturated γ-amino acids. However, through a combination of X-ray crystallography, NMR spectroscopy, FTIR experiments, and DFT calculations, it was determined that the folding behavior of ATC-containing hybrid peptides is much more complex. The homochiral α/(S)-ATC sequences were unable to adopt a stable conformation, whereas the heterochiral α/(R)-ATC peptides displayed novel ribbon structures stabilized by unusual C 9/12 -bifurcated hydrogen bonds. These ribbon structures could be considered as a succession of pre-organized γ/α dipeptides and may provide the basis for designing original α-helix mimics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Peptide based therapeutics and their use for the treatment of neurodegenerative and other diseases.

PubMed

Baig, Mohammad Hassan; Ahmad, Khurshid; Saeed, Mohd; Alharbi, Ahmed M; Barreto, George E; Ashraf, Ghulam Md; Choi, Inho

2018-04-17

Bioactive peptides are actively involved in different biological functions and importantly contribute to human health, and the use of peptides as therapeutics has a long successful history in disease management. A number of peptides have wide-ranging therapeutic effects, such as antioxidant, antimicrobial, and antithrombotic effects. Neurodegenerative diseases are typically caused by abnormal aggregations of proteins or peptides, and the depositions of these aggregates in or on neurons, disrupt signaling and eventually kill neurons. During recent years, research on short peptides has advanced tremendously. This review offers a brief introduction to peptide based therapeutics and their application in disease management and provides an overview of peptide vaccines, and toxicity related issues. In addition, the importance of peptides in the management of different neurodegenerative diseases and their therapeutic applications is discussed. The present review provides an understanding of peptides and their applications for the management of different diseases, but with focus on neurodegenerative diseases. The role of peptides as anti-cancer, antimicrobial and antidiabetic agents has also been discussed. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Novel regenerative large-volume immobilized enzyme reactor: preparation, characterization and application.

PubMed

Ruan, Guihua; Wei, Meiping; Chen, Zhengyi; Su, Rihui; Du, Fuyou; Zheng, Yanjie

2014-09-15

A novel large-volume immobilized enzyme reactor (IMER) on small column was prepared with organic-inorganic hybrid silica particles and applied for fast (10 min) and oriented digestion of protein. At first, a thin enzyme support layer was formed in the bottom of the small column by polymerization with α-methacrylic acid and dimethacrylate. After that, amino SiO2 particles was prepared by the sol-gel method with tetraethoxysilane and 3-aminopropyltriethoxysilane. Subsequently, the amino SiO2 particles were activated by glutaraldehyde for covalent immobilization of trypsin. Digestive capability of large-volume IMER for proteins was investigated by using bovine serum albumin (BSA), cytochrome c (Cyt-c) as model proteins. Results showed that although the sequence coverage of the BSA (20%) and Cyt-c (19%) was low, the large-volume IMER could produce peptides with stable specific sequence at 101-105, 156-160, 205-209, 212-218, 229-232, 257-263 and 473-451 of the amino sequence of BSA when digesting 1mg/mL BSA. Eight of common peptides were observed during each of the ten runs of large-volume IMER. Besides, the IMER could be easily regenerated by reactivating with GA and cross-linking with trypsin after breaking the -C=N- bond by 0.01 M HCl. The sequence coverage of BSA from regenerated IMER increased to 25% comparing the non-regenerated IMER (17%). 14 common peptides. accounting for 87.5% of first use of IMER, were produced both with IMER and regenerated IMER. When the IMER was applied for ginkgo albumin digestion, the sequence coverage of two main proteins of ginkgo, ginnacin and legumin, was 56% and 55%, respectively. (Reviewer 2) Above all, the fast and selective digestion property of the large-volume IMER indicated that the regenerative IMER could be tentatively used for the production of potential bioactive peptides and the study of oriented protein digestion. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioactive Coatings for Orthopaedic Implants—Recent Trends in Development of Implant Coatings

PubMed Central

Zhang, Bill G. X.; Myers, Damian E.; Wallace, Gordon G.; Brandt, Milan; Choong, Peter F. M.

2014-01-01

Joint replacement is a major orthopaedic procedure used to treat joint osteoarthritis. Aseptic loosening and infection are the two most significant causes of prosthetic implant failure. The ideal implant should be able to promote osteointegration, deter bacterial adhesion and minimize prosthetic infection. Recent developments in material science and cell biology have seen the development of new orthopaedic implant coatings to address these issues. Coatings consisting of bioceramics, extracellular matrix proteins, biological peptides or growth factors impart bioactivity and biocompatibility to the metallic surface of conventional orthopaedic prosthesis that promote bone ingrowth and differentiation of stem cells into osteoblasts leading to enhanced osteointegration of the implant. Furthermore, coatings such as silver, nitric oxide, antibiotics, antiseptics and antimicrobial peptides with anti-microbial properties have also been developed, which show promise in reducing bacterial adhesion and prosthetic infections. This review summarizes some of the recent developments in coatings for orthopaedic implants. PMID:25000263

Peptides from Fish By-product Protein Hydrolysates and Its Functional Properties: an Overview.

PubMed

Zamora-Sillero, Juan; Gharsallaoui, Adem; Prentice, Carlos

2018-04-01

The inadequate management of fish processing waste or by-products is one of the major problems that fish industry has to face nowadays. The mismanagement of this raw material leads to economic loss and environmental problems. The demand for the use of these by-products has led to the development of several processes in order to recover biomolecules from fish by-products. An efficient way to add value to fish waste protein is protein hydrolysis. Protein hydrolysates improve the functional properties and allow the release of peptides of different sizes with several bioactivities such as antioxidant, antimicrobial, antihypertensive, anti-inflammatory, or antihyperglycemic among others. This paper reviews different methods for the production of protein hydrolysates as well as current research about several fish by-products protein hydrolysates bioactive properties, aiming the dual objective: adding value to these underutilized by-products and minimizing their negative impact on the environment.

Hydrophobic benzyl amines as supports for liquid-phase C-terminal amidated peptide synthesis: application to the preparation of ABT-510.

PubMed

Matsumoto, Emiko; Fujita, Yuko; Okada, Yohei; Kauppinen, Esko I; Kamiya, Hidehiro; Chiba, Kazuhiro

2015-09-01

C-terminal amidation is one of the most common modification of peptides and frequently found in bioactive peptides. However, the C-terminal modification must be creative, because current chemical synthetic techniques of peptides are dominated by the use of C-terminal protecting supports. Therefore, it must be carried out after the removal of such supports, complicating reaction work-up and product isolation. In this context, hydrophobic benzyl amines were successfully added to the growing toolbox of soluble tag-assisted liquid-phase peptide synthesis as supports, leading to the total synthesis of ABT-510 (2). Although an ethyl amide-forming type was used in the present work, different types of hydrophobic benzyl amines could also be simply designed and prepared through versatile reductive aminations in one step. The standard acidic treatment used in the final deprotection step for peptide synthesis gave the desired C-terminal secondary amidated peptide with no epimerization. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.

Understanding Peptide Oligomeric State in Langmuir Monolayers of Amphiphilic 3-Helix Bundle-Forming Peptide-PEG Conjugates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lund, Reidar; Ang, JooChuan; Shu, Jessica Y.

Coiled-coil peptide-polymer conjugates are an emerging class of biomaterials. Fundamental understanding of the coiled-coil oligomeric state and assembly process of these hybrid building blocks is necessary to exert control over their assembly into well-defined structures. Here in this paper, we studied the effect of peptide structure and PEGylation on the self-assembly process and oligomeric state of a Langmuir monolayer of amphiphilic coiled-coil peptide-polymer conjugates using X-ray reflectivity (XR) and grazing-incidence X-ray diffraction (GIXD). Our results show that the oligomeric state of PEGylated amphiphiles based on 3-helix bundle-forming peptide is surface pressure dependent, a mixture of dimers and trimers was formedmore » at intermediate surface pressure but transitions into trimers completely upon increasing surface pressure. Moreover, the interhelical distance within the coiled-coil bundle of 3-helix peptide-PEG conjugate amphiphiles was not perturbed under high surface pressure. Present studies provide valuable insights into the self-assembly process of hybrid peptide-polymer conjugates and guidance to develop biomaterials with controlled multivalency of ligand presentation.« less

Understanding Peptide Oligomeric State in Langmuir Monolayers of Amphiphilic 3-Helix Bundle-Forming Peptide-PEG Conjugates

DOE PAGES

Lund, Reidar; Ang, JooChuan; Shu, Jessica Y.; ...

2016-10-26

Coiled-coil peptide-polymer conjugates are an emerging class of biomaterials. Fundamental understanding of the coiled-coil oligomeric state and assembly process of these hybrid building blocks is necessary to exert control over their assembly into well-defined structures. Here in this paper, we studied the effect of peptide structure and PEGylation on the self-assembly process and oligomeric state of a Langmuir monolayer of amphiphilic coiled-coil peptide-polymer conjugates using X-ray reflectivity (XR) and grazing-incidence X-ray diffraction (GIXD). Our results show that the oligomeric state of PEGylated amphiphiles based on 3-helix bundle-forming peptide is surface pressure dependent, a mixture of dimers and trimers was formedmore » at intermediate surface pressure but transitions into trimers completely upon increasing surface pressure. Moreover, the interhelical distance within the coiled-coil bundle of 3-helix peptide-PEG conjugate amphiphiles was not perturbed under high surface pressure. Present studies provide valuable insights into the self-assembly process of hybrid peptide-polymer conjugates and guidance to develop biomaterials with controlled multivalency of ligand presentation.« less

Effect of calcium source on structure and properties of sol-gel derived bioactive glasses.

PubMed

Yu, Bobo; Turdean-Ionescu, Claudia A; Martin, Richard A; Newport, Robert J; Hanna, John V; Smith, Mark E; Jones, Julian R

2012-12-18

The aim was to determine the most effective calcium precursor for synthesis of sol-gel hybrids and for improving homogeneity of sol-gel bioactive glasses. Sol-gel derived bioactive calcium silicate glasses are one of the most promising materials for bone regeneration. Inorganic/organic hybrid materials, which are synthesized by incorporating a polymer into the sol-gel process, have also recently been produced to improve toughness. Calcium nitrate is conventionally used as the calcium source, but it has several disadvantages. Calcium nitrate causes inhomogeneity by forming calcium-rich regions, and it requires high temperature treatment (>400 °C) for calcium to be incorporated into the silicate network. Nitrates are also toxic and need to be burnt off. Calcium nitrate therefore cannot be used in the synthesis of hybrids as the highest temperature used in the process is typically 40-60 °C. Therefore, a different precursor is needed that can incorporate calcium into the silica network and enhance the homogeneity of the glasses at low (room) temperature. In this work, calcium methoxyethoxide (CME) was used to synthesize sol-gel bioactive glasses with a range of final processing temperatures from 60 to 800 °C. Comparison is made between the use of CME and calcium chloride and calcium nitrate. Using advanced probe techniques, the temperature at which Ca is incorporated into the network was identified for 70S30C (70 mol % SiO(2), 30 mol % CaO) for each of the calcium precursors. When CaCl(2) was used, the Ca did not seem to enter the network at any of the temperatures used. In contrast, Ca from CME entered the silica network at room temperature, as confirmed by X-ray diffraction, (29)Si magic angle spinning nuclear magnetic resonance spectroscopy, and dissolution studies. CME should be used in preference to calcium salts for hybrid synthesis and may improve homogeneity of sol-gel glasses.

Direct comparison of linear and macrocyclic compound libraries as a source of protein ligands.

PubMed

Gao, Yu; Kodadek, Thomas

2015-03-09

There has been much discussion of the potential desirability of macrocyclic molecules for the development of tool compounds and drug leads. But there is little experimental data comparing otherwise equivalent macrocyclic and linear compound libraries as a source of protein ligands. In this Letter, we probe this point in the context of peptoid libraries. Bead-displayed libraries of macrocyclic and linear peptoids containing four variable positions and 0-2 fixed residues, to vary the ring size, were screened against streptavidin and the affinity of every hit for the target was measured. The data show that macrocyclization is advantageous, but only when the ring contains 17 atoms, not 20 or 23 atoms. This technology will be useful for conducting direct comparisons between many different types of chemical libraries to determine their relative utility as a source of protein ligands.

Mass spectrometry methods for the analysis of biodegradable hybrid materials

NASA Astrophysics Data System (ADS)

Alalwiat, Ahlam

This dissertation focuses on the characterization of hybrid materials and surfactant blends by using mass spectrometry (MS), tandem mass spectrometry (MS/MS), liquid chromatography (LC), and ion mobility (IM) spectrometry combined with measurement and simulation of molecular collision cross sections. Chapter II describes the principles and the history of mass spectrometry (MS) and liquid chromatography (LC). Chapter III introduces the materials and instrumentation used to complete this dissertation. In chapter IV, two hybrid materials containing poly(t-butyl acrylate) (PtBA) or poly(acrylic acid) (PAA) blocks attached to a hydrophobic peptide rich in valine and glycine (VG2), as well as the poly(acrylic acid) (PAA) and VG2 peptide precursor materials, are characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), electrospray ionization mass spectrometry (ESI-MS) and ion mobility mass spectrometry (IM-MS). Collision cross-sections and molecular modeling have been used to determine the final architecture of both hybrid materials. Chapter V investigates a different hybrid material, [BMP-2(HA)2 ], comprised of a dendron with two polyethylene glycol (PEG) branches terminated by a hydroxyapatite binding peptide (HA), and a focal point substituted with a bone morphogenic protein mimicking peptide (BMP-2). MALDI-MS, ESI-MS and IM-MS have been used to characterize the HA and BMP-2 peptides. Collisionally activated dissociation (CAD) and electron transfer dissociation (ETD) have been employed in double stage (i.e. tandem) mass spectrometry (MS/MS) experiments to confirm the sequences of the two peptides HA and BMP-2. The MALDI-MS, ESI-MS and IM-MS methods were also applied to characterize the [BMP-2(HA)2] hybrid material. Collision cross-section measurements and molecular modeling indicated that [BMP-2(HA)2] can attain folded or extended conformation, depending on its degree of protonation (charge state). Chapter VI focuses on the analysis of alkyl polyglycoside (APG) surfactants by MALDI-MS and ESI-MS, MS/MS, and by combining MS and with ion mobility (IM) and/or ultra-performance liquid chromatography (UPLC) separation in LC-IM and LC-IM-MS experiments. Chapter VII summaries this dissertation's findings.

An endo-acting proline-specific oligopeptidase from Treponema denticola ATCC 35405: evidence of hydrolysis of human bioactive peptides.

PubMed Central

Mäkinen, P L; Mäkinen, K K; Syed, S A

1994-01-01

An endo-acting proline-specific oligopeptidase (prolyl oligopeptidase [POPase], EC 3.4.21.26) was purified to homogeneity from the Triton X-100 extracts of cells of Treponema denticola ATCC 35405 (a human oral spirochete) by a procedure that comprised five successive fast protein liquid chromatography steps. The POPase is a cell-associated 75- to 77-kDa protein with an isoelectric point of ca. 6.5. The enzyme hydrolyzed (optimum pH 6.5) the Pro-pNA bond in carbobenzoxy-Gly-Pro-p-nitroanilide (Z-Gly-Pro-pNA) and bonds at the carboxyl side of proline in several human bioactive peptides, such as bradykinin, substance P, neurotensin, angiotensins, oxytocin, vasopressin, and human endothelin fragment 22-38. The minimum hydrolyzable peptide size was tetrapeptide P3P2P1P'1, while the maximum substrate size was ca. 3 kDa. An imino acid residue in position P1 was absolutely necessary. The hydrolysis of Z-Gly-Pro-pNA was potently inhibited by the following, with the Ki(app) (in micromolar) in parentheses: insulin B-chain (0.7), human endothelin-1 (0.5), neuropeptide Y (1.7), substance P (32.0), T-kinin (4.0), neurotensin (5.0), and bradykinin (16.0). Chemical modification and inhibition studies suggest that the POPase is a serine endopeptidase whose activity depends on the catalytic triad of COOH ... Ser ... His but not on a metal. The amino acid sequence around the putative active-site serine is Gly-Gly-Ser-Asn-Pro-Gly. The enzyme is suggested to contain a reactive cysteinyl residue near the active site. Amino acid residues 4 to 24 of the first 24 N-terminal residues showed a homology of 71% with the POPase precursor from Flavobacterium meningosepticum and considerable homology with the Aeromonas hydrophila POPase. The ready hydrolysis of human bioactive peptides at bonds involving an imino acid residue suggests that enzymes like POPase may contribute to the chronicity of periodontal infections by participating in the peptidolytic processing of those peptides. Images PMID:7523301

Biomining of MoS2 with Peptide-based Smart Biomaterials.

PubMed

Cetinel, Sibel; Shen, Wei-Zheng; Aminpour, Maral; Bhomkar, Prasanna; Wang, Feng; Borujeny, Elham Rafie; Sharma, Kumakshi; Nayebi, Niloofar; Montemagno, Carlo

2018-02-20

Biomining of valuable metals using a target specific approach promises increased purification yields and decreased cost. Target specificity can be implemented with proteins/peptides, the biological molecules, responsible from various structural and functional pathways in living organisms by virtue of their specific recognition abilities towards both organic and inorganic materials. Phage display libraries are used to identify peptide biomolecules capable of specifically recognizing and binding organic/inorganic materials of interest with high affinities. Using combinatorial approaches, these molecular recognition elements can be converted into smart hybrid biomaterials and harnessed for biotechnological applications. Herein, we used a commercially available phage-display library to identify peptides with specific binding affinity to molybdenite (MoS 2 ) and used them to decorate magnetic NPs. These peptide-coupled NPs could capture MoS 2 under a variety of environmental conditions. The same batch of NPs could be re-used multiple times to harvest MoS 2 , clearly suggesting that this hybrid material was robust and recyclable. The advantages of this smart hybrid biomaterial with respect to its MoS 2 -binding specificity, robust performance under environmentally challenging conditions and its recyclability suggests its potential application in harvesting MoS 2 from tailing ponds and downstream mining processes.

An iterative glycosyltransferase EntS catalyzes transfer and extension of O- and S-linked monosaccharide in enterocin 96

PubMed Central

Nagar, Rupa; Rao, Alka

2017-01-01

Abstract Glycosyltransferases are essential tools for in vitro glycoengineering. Bacteria harbor an unexplored variety of protein glycosyltransferases. Here, we describe a peptide glycosyltransferase (EntS) encoded by ORF0417 of Enterococcus faecalis TX0104. EntS di-glycosylates linear peptide of enterocin 96 – a known antibacterial, in vitro. It is capable of transferring as well as extending the glycan onto the peptide in an iterative sequential dissociative manner. It can catalyze multiple linkages: Glc/Gal(-O)Ser/Thr, Glc/Gal(-S)Cys and Glc/Gal(β)Glc/Gal(-O/S)Ser/Thr/Cys, in one pot. Using EntS generated glycovariants of enterocin 96 peptide, size and identity of the glycan are found to influence bioactivity of the peptide. The study identifies EntS as an enzyme worth pursuing, for in vitro peptide glycoengineering. PMID:28498962

Peptides Displayed as High Density Brush Polymers Resist Proteolysis and Retain Bioactivity

PubMed Central

2015-01-01

We describe a strategy for rendering peptides resistant to proteolysis by formulating them as high-density brush polymers. The utility of this approach is demonstrated by polymerizing well-established cell-penetrating peptides (CPPs) and showing that the resulting polymers are not only resistant to proteolysis but also maintain their ability to enter cells. The scope of this design concept is explored by studying the proteolytic resistance of brush polymers composed of peptides that are substrates for either thrombin or a metalloprotease. Finally, we demonstrate that the proteolytic susceptibility of peptide brush polymers can be tuned by adjusting the density of the polymer brush and offer in silico models to rationalize this finding. We contend that this strategy offers a plausible method of preparing peptides for in vivo use, where rapid digestion by proteases has traditionally restricted their utility. PMID:25314576

Fatty acid conjugation enhances the activities of antimicrobial peptides.

PubMed

Li, Zhining; Yuan, Penghui; Xing, Meng; He, Zhumei; Dong, Chuanfu; Cao, Yongchang; Liu, Qiuyun

2013-04-01

Antimicrobial peptides are small molecules that play a crucial role in innate immunity in multi-cellular organisms, and usually expressed and secreted constantly at basal levels to prevent infection, but local production can be augmented upon an infection. The clock is ticking as rising antibiotic abuse has led to the emergence of many drug resistance bacteria. Due to their broad spectrum antibiotic and antifungal activities as well as anti-viral and anti-tumor activities, efforts are being made to develop antimicrobial peptides into future microbial agents. This article describes some of the recent patents on antimicrobial peptides with fatty acid conjugation. Potency and selectivity of antimicrobial peptide can be modulated with fatty acid tails of variable length. Interaction between membranes and antimicrobial peptides was affected by fatty acid conjugation. At concentrations above the critical miscelle concentration (CMC), propensity of solution selfassembly hampered binding of the peptide to cell membranes. Overall, fatty acid conjugation has enhanced the activities of antimicrobial peptides, and occasionally it rendered inactive antimicrobial peptides to be bioactive. Antimicrobial peptides can not only be used as medicine but also as food additives.

Effect of Different Heat Treatments on In Vitro Digestion of Egg White Proteins and Identification of Bioactive Peptides in Digested Products.

PubMed

Wang, Xuefen; Qiu, Ning; Liu, Yaping

2018-04-01

Chicken eggs are ingested by people after a series of processes, but to date, only a few studies have explored the nutrient variations caused by different heat treatments. In this work, the impacts of different heat treatments (4, 56, 65, and 100 °C on the in vitro digestibility of egg white proteins were investigated by hydrolysis with pepsin or pepsin + pancreatin to simulate human gastrointestinal digestion, and the digested products were identified using Nano-LC-ESI-MS/MS. Egg white proteins treated at 65 °C had the highest in vitro pepsin digestibility value whereas the pepsin + pancreatin digestibility increased significantly (P < 0.05) as the cooking temperature was raised. The molecular weight distribution of the digested products indicated that, when compared to pepsin-treated samples, pepsin + pancreatin-treated samples contained more low-molecular-weight peptides (m/z < 849.2) with higher signal intensities. The number of unique peptides identified in every digestion product showed a positive correlation with their in vitro digestibility. Additionally, bioactive peptides such as antioxidant, antimicrobial and antihypertensive peptides were found present in egg white digested products, especially in samples treated at 4 and 100 °C. These findings may facilitate a better understanding of nutritive values of egg white proteins and their digested products under different cooking temperatures, such as antibacterial and antioxidant peptides identified in the digestion samples treated, respectively at 4 and 100 °C. This study also provided information for improving the applications of eggs in the food industry as well as a theoretical basis for egg consumption. © 2018 Institute of Food Technologists®.

The singular behavior of a β-type semi-synthetic two branched polypeptide: three-dimensional structure and mode of action.

PubMed

Manzo, Giorgia; Serra, Ilaria; Pira, Alessandro; Pintus, Manuela; Ceccarelli, Matteo; Casu, Mariano; Rinaldi, Andrea C; Scorciapino, Mariano Andrea

2016-11-16

Dendrimeric peptides make a versatile group of bioactive peptidomimetics and a potential new class of antimicrobial agents to tackle the pressing threat of multi-drug resistant pathogens. These are branched supramolecular assemblies where multiple copies of the bioactive unit are linked to a central core. Beyond their antimicrobial activity, dendrimeric peptides could also be designed to functionalize the surface of nanoparticles or materials for other medical uses. Despite these properties, however, little is known about the structure-function relationship of such compounds, which is key to unveil the fundamental physico-chemical parameters and design analogues with desired attributes. To close this gap, we focused on a semi-synthetic, two-branched peptide, SB056, endowed with remarkable activity against both Gram-positive and Gram-negative bacteria and limited cytotoxicity. SB056 can be considered the smallest prototypical dendrimeric peptide, with the core restricted to a single lysine residue and only two copies of the same highly cationic 10-mer polypeptide; an octanamide tail is present at the C-terminus. Combining NMR and Molecular Dynamics simulations, we have determined the 3D structure of two analogues. Fluorescence spectroscopy was applied to investigate the water-bilayer partition in the presence of vesicles of variable charge. Vesicle leakage assays were also performed and the experimental data were analyzed by applying an iterative Monte Carlo scheme to estimate the minimum number of bound peptides needed to achieve the release. We unveiled a singular beta hairpin-type structure determined by the peptide chains only, with the octanamide tail available for further functionalization to add new potential properties without affecting the structure.

The cell-specific pattern of cholecystokinin peptides in endocrine cells versus neurons is governed by the expression of prohormone convertases 1/3, 2, and 5/6.

PubMed

Rehfeld, Jens F; Bundgaard, Jens R; Hannibal, Jens; Zhu, Xiaorong; Norrbom, Christina; Steiner, Donald F; Friis-Hansen, Lennart

2008-04-01

Most peptide hormone genes are, in addition to endocrine cells, also expressed in neurons. The peptide hormone cholecystokinin (CCK) is expressed in different molecular forms in cerebral neurons and intestinal endocrine cells. To understand this difference, we examined the roles of the neuroendocrine prohormone convertases (PC) 1/3, PC2, and PC5/6 by measurement of proCCK, processing intermediates and bioactive, alpha-amidated, and O-sulfated CCK peptides in cerebral and jejunal extracts of null mice, controls, and in the PC5/6-expressing SK-N-MC cell-line. In PC1/3 null mice, the synthesis of bioactive CCK peptide in the gut was reduced to 3% of the translational product, all of which was in the form of alpha-amidated and tyrosine O-sulfated CCK-22, whereas the neuronal synthesis in the brain was largely unaffected. This is opposite to the PC2 null mice in which only the cerebral synthesis was affected. SK-N-MC cells, which express neither PC1/3 nor PC2, synthesized alone the processing intermediate, glycine-extended CCK-22. Immunocytochemistry confirmed that intestinal endocrine CCK cells in wild-type mice express PC1/3 but not PC2. In contrast, cerebral CCK neurons contain PC2 and only little, if any, PC1/3. Taken together, the data indicate that PC1/3 governs the endocrine and PC2 the neuronal processing of proCCK, whereas PC5/6 contributes only to a modest endocrine synthesis of CCK-22. The results suggest that the different peptide patterns in the brain and the gut are due to different expression of PCs.

Epitope topography controls bioactivity in supramolecular nanofibers

PubMed Central

Sur, Shantanu; Tantakitti, Faifan; Matson, John B.; Stupp, Samuel I.

2015-01-01

Incorporating bioactivity into artificial scaffolds using peptide epitopes present in the extracellular matrix (ECM) is a well-known approach. A common strategy has involved epitopes that provide cells with attachment points and external cues through interaction with integrin receptors. Although a variety of bioactive sequences have been identified so far, less is known about their optimal display in a scaffold. We report here on the use of self-assembled peptide amphiphile (PA) nanofiber matrices to investigate the impact of spatial presentation of the fibronectin derived epitope RGDS on cell response. Using one, three, or five glycine residues, RGDS epitopes were systematically spaced out from the surface of the rigid nanofibers. We found that cell morphology was strongly affected by the separation of the epitope from the nanofiber surface, with the longest distance yielding the most cell-spreading, bundling of actin filaments, and a round-to-polygonal transformation of cell shape. Cell response to this type of epitope display was also accompanied with activated integrin-mediated signaling and formation of stronger adhesions between cells and substrate. Interestingly, unlike length, changing the molecular flexibility of the linker had minimal influence on cell behavior on the substrate for reasons that remain poorly understood. The use in this study of high persistence length nanofibers rather than common flexible polymers allows us to conclude that epitope topography at the nanoscale structure of a scaffold influences its bioactive properties independent of epitope density and mechanical properties. PMID:25745558

Cheese whey: A potential resource to transform into bioprotein, functional/nutritional proteins and bioactive peptides.

PubMed

Yadav, Jay Shankar Singh; Yan, Song; Pilli, Sridhar; Kumar, Lalit; Tyagi, R D; Surampalli, R Y

2015-11-01

The byproduct of cheese-producing industries, cheese whey, is considered as an environmental pollutant due to its high BOD and COD concentrations. The high organic load of whey arises from the presence of residual milk nutrients. As demand for milk-derived products is increasing, it leads to increased production of whey, which poses a serious management problem. To overcome this problem, various technological approaches have been employed to convert whey into value-added products. These technological advancements have enhanced whey utilization and about 50% of the total produced whey is now transformed into value-added products such as whey powder, whey protein, whey permeate, bioethanol, biopolymers, hydrogen, methane, electricity bioprotein (single cell protein) and probiotics. Among various value-added products, the transformation of whey into proteinaceous products is attractive and demanding. The main important factor which is attractive for transformation of whey into proteinaceous products is the generally recognized as safe (GRAS) regulatory status of whey. Whey and whey permeate are biotransformed into proteinaceous feed and food-grade bioprotein/single cell protein through fermentation. On the other hand, whey can be directly processed to obtain whey protein concentrate, whey protein isolate, and individual whey proteins. Further, whey proteins are also transformed into bioactive peptides via enzymatic or fermentation processes. The proteinaceous products have applications as functional, nutritional and therapeutic commodities. Whey characteristics, and its transformation processes for proteinaceous products such as bioproteins, functional/nutritional protein and bioactive peptides are covered in this review. Copyright © 2015 Elsevier Inc. All rights reserved.

The identification of goat peroxiredoxin-5 and the evaluation and enhancement of its stability by nanoparticle formation

PubMed Central

Feng, Xiaozhou; Liu, Juanjuan; Fan, Shuai; Liu, Fan; Li, Yadong; Jin, Yuanyuan; Bai, Liping; Yang, Zhaoyong

2016-01-01

An anticancer bioactive peptide (ACBP), goat peroxiredoxin-5 (gPRDX5), was identified from goat-spleen extract after immunizing the goat with gastric cancer-cell lysate. Its amino acid sequence was determined by employing 2D nano-LC-ESI-LTQ-Orbitrap MS/MS combined with Mascot database search in the goat subset of the Uniprot database. The recombinant gPRDX5 protein was acquired by heterogeneous expression in Escherichia coli. Subsequently, the anti-cancer bioactivity of the peptide was measured by several kinds of tumor cells. The results indicated that the gPRDX5 was a good anti-cancer candidate, especially for killing B16 cells. However, the peptide was found to be unstable without modification with pharmaceutical excipients, which would be a hurdle for future medicinal application. In order to overcome this problem and find an effective way to evaluate the gPRDX5, nanoparticle formation, which has been widely used in drug delivery because of its steadiness in application, less side-effects and enhancement of drug accumulation in target issues, was used here to address the issues. In this work, the gPRDX5 was dispersed into nanoparticles before delivered to B16 cells. By the nanotechnological method, the gPRDX5 was stabilized by a fast and accurate procedure, which suggests a promising way for screening the peptide for further possible medicinal applications. PMID:27074889

The identification of goat peroxiredoxin-5 and the evaluation and enhancement of its stability by nanoparticle formation.

PubMed

Feng, Xiaozhou; Liu, Juanjuan; Fan, Shuai; Liu, Fan; Li, Yadong; Jin, Yuanyuan; Bai, Liping; Yang, Zhaoyong

2016-04-14

An anticancer bioactive peptide (ACBP), goat peroxiredoxin-5 (gPRDX5), was identified from goat-spleen extract after immunizing the goat with gastric cancer-cell lysate. Its amino acid sequence was determined by employing 2D nano-LC-ESI-LTQ-Orbitrap MS/MS combined with Mascot database search in the goat subset of the Uniprot database. The recombinant gPRDX5 protein was acquired by heterogeneous expression in Escherichia coli. Subsequently, the anti-cancer bioactivity of the peptide was measured by several kinds of tumor cells. The results indicated that the gPRDX5 was a good anti-cancer candidate, especially for killing B16 cells. However, the peptide was found to be unstable without modification with pharmaceutical excipients, which would be a hurdle for future medicinal application. In order to overcome this problem and find an effective way to evaluate the gPRDX5, nanoparticle formation, which has been widely used in drug delivery because of its steadiness in application, less side-effects and enhancement of drug accumulation in target issues, was used here to address the issues. In this work, the gPRDX5 was dispersed into nanoparticles before delivered to B16 cells. By the nanotechnological method, the gPRDX5 was stabilized by a fast and accurate procedure, which suggests a promising way for screening the peptide for further possible medicinal applications.

Human Milk: Bioactive Proteins/Peptides and Functional Properties.

PubMed

Lönnerdal, Bo

2016-06-23

Breastfeeding has been associated with many benefits, both in the short and in the long term. Infants being breastfed generally have less illness and have better cognitive development at 1 year of age than formula-fed infants. Later in life, they have a lower risk of obesity, diabetes and cardiovascular disease. Several components in breast milk may be responsible for these different outcomes, but bioactive proteins/peptides likely play a major role. Some proteins in breast milk are comparatively resistant towards digestion and may therefore exert their functions in the gastrointestinal tract in intact form or as larger fragments. Other milk proteins may be partially digested in the upper small intestine and the resulting peptides may exert functions in the lower small intestine. Lactoferrin, lysozyme and secretory IgA have been found intact in the stool of breastfed infants and are therefore examples of proteins that are resistant against proteolytic degradation in the gut. Together, these proteins serve protective roles against infection and support immune function in the immature infant. α-lactalbumin, β-casein, κ-casein and osteopontin are examples of proteins that are partially digested in the upper small intestine, and the resulting peptides influence functions in the gut. Such functions include stimulation of immune function, mineral and trace element absorption and defense against infection. © 2016 Nestec Ltd., Vevey/S. Karger AG, Basel.

The identification of goat peroxiredoxin-5 and the evaluation and enhancement of its stability by nanoparticle formation

NASA Astrophysics Data System (ADS)

Feng, Xiaozhou; Liu, Juanjuan; Fan, Shuai; Liu, Fan; Li, Yadong; Jin, Yuanyuan; Bai, Liping; Yang, Zhaoyong

2016-04-01

An anticancer bioactive peptide (ACBP), goat peroxiredoxin-5 (gPRDX5), was identified from goat-spleen extract after immunizing the goat with gastric cancer-cell lysate. Its amino acid sequence was determined by employing 2D nano-LC-ESI-LTQ-Orbitrap MS/MS combined with Mascot database search in the goat subset of the Uniprot database. The recombinant gPRDX5 protein was acquired by heterogeneous expression in Escherichia coli. Subsequently, the anti-cancer bioactivity of the peptide was measured by several kinds of tumor cells. The results indicated that the gPRDX5 was a good anti-cancer candidate, especially for killing B16 cells. However, the peptide was found to be unstable without modification with pharmaceutical excipients, which would be a hurdle for future medicinal application. In order to overcome this problem and find an effective way to evaluate the gPRDX5, nanoparticle formation, which has been widely used in drug delivery because of its steadiness in application, less side-effects and enhancement of drug accumulation in target issues, was used here to address the issues. In this work, the gPRDX5 was dispersed into nanoparticles before delivered to B16 cells. By the nanotechnological method, the gPRDX5 was stabilized by a fast and accurate procedure, which suggests a promising way for screening the peptide for further possible medicinal applications.

Metabolism of Cryptic Peptides Derived from Neuropeptide FF Precursors: The Involvement of Insulin-Degrading Enzyme

PubMed Central

Grasso, Giuseppe; Mielczarek, Przemyslaw; Niedziolka, Magdalena; Silberring, Jerzy

2014-01-01

The term “cryptome” refers to the subset of cryptic peptides with bioactivities that are often unpredictable and very different from the parent protein. These cryptic peptides are generated by proteolytic cleavage of proteases, whose identification in vivo can be very challenging. In this work, we show that insulin-degrading enzyme (IDE) is able to degrade specific amino acid sequences present in the neuropeptide pro-NPFFA (NPFF precursor), generating some cryptic peptides that are also observed after incubation with rat brain cortex homogenate. The reported experimental findings support the increasingly accredited hypothesis, according to which, due to its wide substrate selectivity, IDE is involved in a wide variety of physiopathological processes. PMID:25247577

Characterization and identification of a chymotryptic hydrolysate of alpha-lactalbumin stimulating cholecystokinin release in STC-1 cells.

PubMed

Catiau, Lucie; Delval-Dubois, Véronique; Guillochon, Didier; Nedjar-Arroume, Naïma

2011-11-01

Alpha-lactalbumin hydrolysate is of significant interest, due to its potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. This study was focused on the cholecystokinin (CCK) family compounds which are small peptides involved in the satiety control. The action of chymotryptic hydrolysate of alpha-lactalbumin on cholecystokinin release from intestinal endocrine STC-1 cells was investigated. We demonstrated for the first time that a chymotryptic hydrolysate of alpha-lactalbumin was able to highly stimulate CCK-releasing activity from STC-1 cells. The peptidic hydrolysate was characterized by LC/MS and MS/MS, thus highlighting the presence of 11 fractions containing 21 peptides, each potentially having the desired activity.

Improved Glucose Control and Reduced Body Weight in Rodents with Dual Mechanism of Action Peptide Hybrids

PubMed Central

Trevaskis, James L.; Mack, Christine M.; Sun, Chengzao; Soares, Christopher J.; D’Souza, Lawrence J.; Levy, Odile E.; Lewis, Diane Y.; Jodka, Carolyn M.; Tatarkiewicz, Krystyna; Gedulin, Bronislava; Gupta, Swati; Wittmer, Carrie; Hanley, Michael; Forood, Bruce; Parkes, David G.; Ghosh, Soumitra S.

2013-01-01

Combination therapy is being increasingly used as a treatment paradigm for metabolic diseases such as diabetes and obesity. In the peptide therapeutics realm, recent work has highlighted the therapeutic potential of chimeric peptides that act on two distinct receptors, thereby harnessing parallel complementary mechanisms to induce additive or synergistic benefit compared to monotherapy. Here, we extend this hypothesis by linking a known anti-diabetic peptide with an anti-obesity peptide into a novel peptide hybrid, which we termed a phybrid. We report on the synthesis and biological activity of two such phybrids (AC164204 and AC164209), comprised of a glucagon-like peptide-1 receptor (GLP1-R) agonist, and exenatide analog, AC3082, covalently linked to a second generation amylin analog, davalintide. Both molecules acted as full agonists at their cognate receptors in vitro, albeit with reduced potency at the calcitonin receptor indicating slightly perturbed amylin agonism. In obese diabetic Lepob/Lep ob mice sustained infusion of AC164204 and AC164209 reduced glucose and glycated haemoglobin (HbA1c) equivalently but induced greater weight loss relative to exenatide administration alone. Weight loss was similar to that induced by combined administration of exenatide and davalintide. In diet-induced obese rats, both phybrids dose-dependently reduced food intake and body weight to a greater extent than exenatide or davalintide alone, and equal to co-infusion of exenatide and davalintide. Phybrid-mediated and exenatide + davalintide-mediated weight loss was associated with reduced adiposity and preservation of lean mass. These data are the first to provide in vivo proof-of-concept for multi-pathway targeting in metabolic disease via a peptide hybrid, demonstrating that this approach is as effective as co-administration of individual peptides. PMID:24167604

Efficient functionalization of alginate biomaterials.

PubMed

Dalheim, Marianne Ø; Vanacker, Julie; Najmi, Maryam A; Aachmann, Finn L; Strand, Berit L; Christensen, Bjørn E

2016-02-01

Peptide coupled alginates obtained by chemical functionalization of alginates are commonly used as scaffold materials for cells in regenerative medicine and tissue engineering. We here present an alternative to the commonly used carbodiimide chemistry, using partial periodate oxidation followed by reductive amination. High and precise degrees of substitution were obtained with high reproducibility, and without formation of by-products. A protocol was established using l-Tyrosine methyl ester as a model compound and the non-toxic pic-BH3 as the reducing agent. DOSY was used to indirectly verify covalent binding and the structure of the product was further elucidated using NMR spectroscopy. The coupling efficiency was to some extent dependent on alginate composition, being most efficient on mannuronan. Three different bioactive peptide sequences (GRGDYP, GRGDSP and KHIFSDDSSE) were coupled to 8% periodate oxidized alginate resulting in degrees of substitution between 3.9 and 6.9%. Cell adhesion studies of mouse myoblasts (C2C12) and human dental stem cells (RP89) to gels containing various amounts of GRGDSP coupled alginate demonstrated the bioactivity of the material where RP89 cells needed higher peptide concentrations to adhere. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bioactive peptides from selected latin american food crops - A nutraceutical and molecular approach.

PubMed

Orona-Tamayo, Domancar; Valverde, María Elena; Paredes-López, Octavio

2018-02-01

This review reported an updated survey on the molecular functional properties of bioactive peptides derived from different Latin American ancient grains such as Maize, common Bean, Amaranth, Quinoa and Chia seeds. Seed storage proteins ecrypt in their sequences diverse peptides associated with a wide range of beneficial effects on the human health and the most studied are antihypertensive, anti-cholesterolemic, antioxidant, anti-inflammatory, anticancer, antimicrobial and immunomodulatory properties. Additionally, in the last decades molecular properties have been also used for their characterization to understand their activities and it makes them highly attractive to be incorporated into food formulations and to complement or replace some conventional cereal grains. Due to the nutraceutical effects, today, these seeds are one of the main gastronomic trends of consumption worldwide due to their nutritional benefits and are part of the shopping lists of many people, among them vegetarians, vegans, celiacs or lovers of raw food. These seeds are a legacy of pre-Columbian civilizations reason why in our time they are considered as "Superfoods of the Gods", "The pre-hispanic superfoods of the future" and "The new golden seeds of the XXI century".

In Conversation With Materials Scientist Ron Zuckermann

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ron Zuckerman

2009-11-18

Nov. 11, 2009: Host Alice Egan of Berkeley Lab's Materials Sciences Division interviews scientists about their lives and work in language everyone can understand. Her guest Berkeley Lab's Ron Zuckerman, who discusses biological nanostructures and the world of peptoids.

In Conversation With Materials Scientist Ron Zuckermann

ScienceCinema

Ron Zuckerman

2017-12-09

Nov. 11, 2009: Host Alice Egan of Berkeley Lab's Materials Sciences Division interviews scientists about their lives and work in language everyone can understand. Her guest Berkeley Lab's Ron Zuckerman, who discusses biological nanostructures and the world of peptoids.

Sequential and competitive adsorption of peptides at pendant PEO layers.

PubMed

Wu, Xiangming; Ryder, Matthew P; McGuire, Joseph; Snider, Joshua L; Schilke, Karl F

2015-06-01

Earlier work provided direction for development of responsive drug delivery systems based on modulation of the structure, amphiphilicity, and surface density of bioactive peptides entrapped within pendant polyethylene oxide (PEO) brush layers. In this work, we describe the sequential and competitive adsorption behavior of such peptides at pendant PEO layers. Three cationic peptides were used for this purpose: the arginine-rich, amphiphilic peptide WLBU2, a peptide chemically identical to WLBU2 but of scrambled sequence (S-WLBU2), and the non-amphiphilic peptide poly-L-arginine (PLR). Optical waveguide lightmode spectroscopy (OWLS) was used to quantify the rate and extent of peptide adsorption and elution at surfaces coated with PEO. UV spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS) were used to quantify the extent of peptide exchange during the course of sequential and competitive adsorption. Circular dichroism (CD) was used to evaluate conformational changes after adsorption of peptide mixtures at PEO-coated silica nanoparticles. Results indicated that amphiphilic peptides are able to displace adsorbed, non-amphiphilic peptides in PEO layers, while non-amphiphilic peptides were not able to displace more amphiphilic peptides. In addition, peptides of greater amphiphilicity dominated the adsorption at the PEO layer from mixtures with less amphiphilic or non-amphiphilic peptides. Copyright © 2015 Elsevier B.V. All rights reserved.

Collagen like peptide bioconjugates for targeted drug delivery applications

NASA Astrophysics Data System (ADS)

Luo, Tianzhi

Collagen is the most abundant protein in mammals, and there has been long-standing interest in understanding and controlling collagen assembly in the design of new materials. Collagen-like peptides (CLP), also known as collagen-mimetic peptides (CMP), are short synthetic peptides which mimic the triple helical conformation of native collagens. In the past few decades, collagen like peptides and their conjugated hybrids have become a new class of biomaterials that possesses unique structures and properties. In addition to traditional applications of using CLPs to decipher the role of different amino acid residues and tripeptide motifs in stabilizing the collagen triple helix and mimicking collagen fibril formation, with the introduction of specific interactions including electrostatic interactions, pi-pi stacking interaction and metal-ligand coordination, a variety of artificial collagen-like peptides with well-defined sequences have been designed to create higher order assemblies with specific biological functions. The CLPs have also been widely used as bioactive domains or physical cross-linkers to fabricate hydrogels, which have shown potential to improve cell adhesion, proliferation and ECM macromolecule production. Despite this widespread use, the utilization of CLPs as domains in stimuli responsive bioconjugates represents a relatively new area for the development of functional polymeric materials. In this work, a new class of thermoresponsive diblock conjugates, containing collagen-like peptides and a thermoresponsive polymer, namely poly(diethylene glycol methyl ether methacrylate) (PDEGMEMA), is introduced. The CLP domain maintains its triple helix conformation after conjugation with the polymer. The engineered LCST of these conjugates has enabled temperature-induced assembly under aqueous conditions, at physiologically relevant temperatures, into well-defined vesicles with diameters of approximately 50-200 nm. The formation of nanostructures was driven by the coil/globule conformational transition of the PDEGMEMA building block above its LCST with stabilization of the nanostructures by the hydrophilic CLP. To the best of our knowledge, this is the first report on such assembled nanostructures from collagen-like peptide containing copolymers. Due to the strong propensity for CLPs to bind to natural collagen via strand invasion processes, these nanosized vesicles may be used as drug carriers for targeted delivery. In addition to synthetic polymers, the collagen like peptide is then conjugated with a thermoresponsive elastin-like peptide (ELP). The resulting ELP-CLP diblock conjugates show a remarkable reduction in the inverse transition temperature of the ELP domain, attributed to the anchoring effect of the CLP triple helix. The lower transition temperature of the conjugate enables facile formation of well-defined vesicles at physiological temperature and the unexpected resolubilization of the vesicles at elevated temperatures upon unfolding of the CLP domain. Given the ability of CLPs to modify collagens, this work provides not only a simple and versatile avenue for controlling the inverse transition behavior of elastin-like peptides, but also suggest future opportunities for these thermoresponsive nanostructures in biologically relevant environments. In the last section, the potential of using the ELP-CLP nanoparticles as drug delivery vehicles for targeting collagen containing matrices is evaluated. A sustained release of clinically relevant amount of encapsulated modelled drug is achieved within three weeks, followed by a thermally controlled burst release. As expected, the ELP-CLP nanoparticles show strong retention on collagen substrate, via specific binding through collagen triple helix hybridization. Additionally, cell viability and proliferation studies using fibroblasts and chondrocytes suggest the nanoparticles are non-cytotoxic. Additionally, almost no TNF-alpha expression from macrophages is observed, suggesting that the nanoparticles do not initiate inflammatory response. Endowed with specific collagen binding, controlled thermoresponsiveness, excellent cytocompatibility, and non-immune responsiveness, we believe the ELP-CLP nanoparticles are promising candidates as drug delivery vehicles for targeting collagen containing matrices. Considering the critical role of collagens in extracellular matrix and the unique ability of the CLP to target native collagens, our work offers significant opportunities for the design of collagen-like peptides and their bioconjugates for targeted application in the biomedical arena.

Ribosomally Synthesized and Post-translationally Modified Peptide Natural Products: New Insights Into the Role of Leader and Core Peptides During Biosynthesis

PubMed Central

Yang, Xiao; van der Donk, Wilfred A.

2013-01-01

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a major class of natural products with a high degree of structural diversity and a wide variety of bioactivities. Understanding the biosynthetic machinery of these RiPPs will benefit the discovery and development of new molecules with potential pharmaceutical applications. In this review, we discuss the features of the biosynthetic pathways to different RiPP classes, and propose mechanisms regarding recognition of the precursor peptide by the posttranslational modification enzymes. We propose that the leader peptides function as allosteric regulators that bind the active form of the biosynthetic enzymes in a conformational selection process. We also speculate how enzymes that generate polycyclic products of defined topologies may have been selected for during evolution. PMID:23666908

Isolation and characterization of cDNA clones for carrot extensin and a proline-rich 33-kDa protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, J.; Varner, J.E.

1985-07-01

Extensins are hydroxyproline-rich glycoproteins associated with most dicotyledonous plant cell walls. To isolate cDNA clones encoding extensin, the authors started by isolating poly(A) RNA from carrot root tissue, and then translating the RNA in vitro, in the presence of tritiated leucine or proline. A 33-kDa peptide was identified in the translation products as a putative extensin precursor. From a cDNA library constructed with poly(A) RNA from wounded carrots, one cDNA clone (pDC5) was identified that specifically hybridized to poly(A) RNA encoding this 33-kDa peptide. They isolated three cDNA clones (pDC11, pDC12, and pDC16) from another cDNA library using pCD5 asmore » a probe. DNA sequence data, RNA hybridization analysis, and hybrid released in vitro translation indicate that the cDNA clones pDC11 encodes extensin and that cDNA clones pDC12 and pDC16 encode the 33-kDa peptide, which as yet has an unknown identity and function. The assumption that the 33-kDa peptide was an extensin precursor was invalid. RNA hybridization analysis showed that RNA encoded by both clone types is accumulated upon wounding.« less

Analysis of the endogenous peptide profile of milk: identification of 248 mainly casein-derived peptides.

PubMed

Baum, Florian; Fedorova, Maria; Ebner, Jennifer; Hoffmann, Ralf; Pischetsrieder, Monika

2013-12-06

Milk is an excellent source of bioactive peptides. However, the composition of the native milk peptidome has only been partially elucidated. The present study applied matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) directly or after prefractionation of the milk peptides by reverse-phase high-performance liquid chromatography (RP-HPLC) or OFFGEL fractionation for the comprehensive analysis of the peptide profile of raw milk. The peptide sequences were determined by MALDI-TOF/TOF or nano-ultra-performance liquid chromatography-nanoelectrospray ionization-LTQ-Orbitrap-MS. Direct MALDI-TOF-MS analysis led to the assignment of 57 peptides. Prefractionation by both complementary methods led to the assignment of another 191 peptides. Most peptides originate from α(S1)-casein, followed by β-casein, and α(S2)-casein. κ-Casein and whey proteins seem to play only a minor role as peptide precursors. The formation of many, but not all, peptides could be explained by the activity of the endogenous peptidases, plasmin or cathepsin D, B, and G. Database searches revealed the presence of 22 peptides with established physiological function, including those with angiotensin-converting-enzyme (ACE) inhibitory, immunomodulating, or antimicrobial activity.

Design of Decorated Self-Assembling Peptide Hydrogels as Architecture for Mesenchymal Stem Cells

PubMed Central

Zamuner, Annj; Cavo, Marta; Scaglione, Silvia; Messina, Grazia Maria Lucia; Russo, Teresa; Gloria, Antonio; Marletta, Giovanni; Dettin, Monica

2016-01-01

Hydrogels from self-assembling ionic complementary peptides have been receiving a lot of interest from the scientific community as mimetic of the extracellular matrix that can offer three-dimensional supports for cell growth or can become vehicles for the delivery of stem cells, drugs or bioactive proteins. In order to develop a 3D “architecture” for mesenchymal stem cells, we propose the introduction in the hydrogel of conjugates obtained by chemoselective ligation between a ionic-complementary self-assembling peptide (called EAK) and three different bioactive molecules: an adhesive sequence with 4 Glycine-Arginine-Glycine-Aspartic Acid-Serine-Proline (GRGDSP) motifs per chain, an adhesive peptide mapped on h-Vitronectin and the growth factor Insulin-like Growth Factor-1 (IGF-1). The mesenchymal stem cell adhesion assays showed a significant increase in adhesion and proliferation for the hydrogels decorated with each of the synthesized conjugates; moreover, such functionalized 3D hydrogels support cell spreading and elongation, validating the use of this class of self-assembly peptides-based material as very promising 3D model scaffolds for cell cultures, at variance of the less realistic 2D ones. Furthermore, small amplitude oscillatory shear tests showed that the presence of IGF-1-conjugate did not alter significantly the viscoelastic properties of the hydrogels even though differences were observed in the nanoscale structure of the scaffolds obtained by changing their composition, ranging from long, well-defined fibers for conjugates with adhesion sequences to the compact and dense film for the IGF-1-conjugate. PMID:28773852

Antioxidant activity of protein hydrolysates from raw and heat-treated yellow string beans (Phaseolus vulgaris L.).

PubMed

Karaś, Monika; Jakubczyk, Anna; Szymanowska, Urszula; Materska, Małgorzata; Zielińska, Ewelina

2014-01-01

Nowadays, legume plants have been considered not only a source of valuable proteins necessary for the proper functioning and growth of the body but also a source of bioactive compounds such as bioactive peptides, that may be beneficial to human health and protect against negative change in food. The aim of this study was to investigate the effect of heat treatment on the release of antioxidant peptides obtained by hydrolysis of the yellow string beans protein. The antioxidant properties of the hydrolysates were evaluated through free radical scavenging activities (DPPH and ABTS) and inhibition of iron activities (chelation of Fe2+). The results show that the heat treatment had influence on both increased peptides content and antioxidant activity after pepsin hydrolysis of string bean protein. The peptides content after protein hydrolysis derived from raw and heat treated beans were noted 2.10 and 2.50 mg·ml-1, respectively. The hydrolysates obtained from raw (PHR) and heat treated (PHT) beans showed better antioxidant properties than protein isolates (PIR and PIT). Moreover, the hydrolysates obtained from heat treated beans showed the higher ability to scavenge DPPH• (46.12%) and ABTS+• (92.32%) than obtained from raw beans (38.02% and 88.24%, correspondingly). The IC50 value for Fe2+ chelating ability for pepsin hydrolysates obtained from raw and heat treatment beans were noted 0.81 and 0.19 mg·ml-1, respectively. In conclusion, the results of this study showed that the heat treatment string beans caused increase in the antioxidant activities of peptide-rich hydrolysates.

Antioxidant and ACE Inhibitory Bioactive Peptides Purified from Egg Yolk Proteins

PubMed Central

Yousr, Marwa; Howell, Nazlin

2015-01-01

Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF). Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS) in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y) and tryptophan (W), in sequences identified by LC-MS as WYGPD (EYGF-23) and KLSDW (EYGF-33), contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56) was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69%) and IC50 value (3.35 mg/mL). The SDNRNQGY peptide (10 mg/mL) had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL). In addition, YPSPV in (EYGF-33) (10 mg/mL) had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk. PMID:26690134

Antioxidant and ACE Inhibitory Bioactive Peptides Purified from Egg Yolk Proteins.

PubMed

Yousr, Marwa; Howell, Nazlin

2015-12-07

Protein by-products from the extraction of lecithin from egg yolk can be converted into value-added products, such as bioactive hydrolysates and peptides that have potential health enhancing antioxidant, and antihypertensive properties. In this study, the antioxidant and angiotensin converting enzyme (ACE) inhibitory activities of peptides isolated and purified from egg yolk protein were investigated. Defatted egg yolk was hydrolyzed using pepsin and pancreatin and sequentially fractionated by ultrafiltration, followed by gel filtration to produce egg yolk gel filtration fractions (EYGF). Of these, two fractions, EYGF-23 and EYGF-33, effectively inhibited the peroxides and thiobarbituric acid reactive substance (TBARS) in an oxidizing linoleic acid model system. The antioxidant mechanism involved superoxide anion and hydroxyl radicals scavenging and ferrous chelation. The presence of hydrophobic amino acids such as tyrosine (Y) and tryptophan (W), in sequences identified by LC-MS as WYGPD (EYGF-23) and KLSDW (EYGF-33), contributed to the antioxidant activity and were not significantly different from the synthetic BHA antioxidant. A third fraction (EYGF-56) was also purified from egg yolk protein by gel filtration and exhibited high ACE inhibitory activity (69%) and IC50 value (3.35 mg/mL). The SDNRNQGY peptide (10 mg/mL) had ACE inhibitory activity, which was not significantly different from that of the positive control captopril (0.5 mg/mL). In addition, YPSPV in (EYGF-33) (10 mg/mL) had higher ACE inhibitory activity compared with captopril. These findings indicated a substantial potential for producing valuable peptides with antioxidant and ACE inhibitory activity from egg yolk.

Survival and bioactivities of selected probiotic lactobacilli in yogurt fermentation and cold storage: New insights for developing a bi-functional dairy food.

PubMed

Rutella, Giuseppina Sefora; Tagliazucchi, Davide; Solieri, Lisa

2016-12-01

In previous work, we demonstrated that two probiotic strains, namely Lactobacillus casei PRA205 and Lactobacillus rhamnosus PRA331, produce fermented milks with potent angiotensin-converting enzyme (ACE)-inhibitory and antioxidant activities. Here, we tested these strains for the survivability and the release of antihypertensive and antioxidant peptides in yogurt fermentation and cold storage. For these purposes three yogurt batches were compared: one prepared using yogurt starters alone (Lactobacillus delbrueckii subspecies bulgaricus 1932 and Streptococcus thermophilus 99), and the remaining two containing either PRA205 or PRA331 in addition to yogurt starters. Despite the lower viable counts at the fermentation end compared to PRA331, PRA205 overcame PRA331 in survivability during refrigerated storage for 28 days, leading to viable counts (>10(8) CFU/g) higher than the minimum therapeutic threshold (10(6) CFU/g). Analyses of in vitro ACE-inhibitory and antioxidant activities of peptide fractions revealed that yogurt supplemented with PRA205 displays higher amounts of antihypertensive and antioxidant peptides than that produced with PRA331 at the end of fermentation and over storage. Two ACE-inhibitory peptides, Valine-Proline-Proline (VPP) and Isoleucine-Proline-Proline (IPP), were identified and quantified. This study demonstrated that L. casei PRA205 could be used as adjunct culture for producing bi-functional yogurt enriched in bioactive peptides and in viable cells, which bring health benefits to the host as probiotics. Copyright © 2016 Elsevier Ltd. All rights reserved.

Investigating the effect of peptide agonists on the chondrogenic differentiation of human mesenchymal stem cells using design of experiments.

PubMed

Renner, Julie N; Liu, Julie C

2013-01-01

Human mesenchymal stem cells (MSCs) are attractive for use in cartilage tissue engineering. Cells are often seeded in a structural scaffold containing growth factors. Peptide mimics of full-length growth factors are a promising alternative because they are less expensive and easier to manufacture. We investigated four short peptides for their effect on the chondrogenesis of human MSCs. The peptides were originally designed to mimic bone morphogenetic protein-2 (BMP-2), transforming growth factor-beta 1 (TGF-β1), and insulin, all of which have been shown to affect MSC chondrogenesis. Previous studies demonstrated that the peptides elicited bioactivity in other cell types, but the peptides have not been investigated for their effect on chondrogenesis in human MSCs. In a preliminary investigation, peptides were added to a pellet culture of human MSCs and assayed for their effect on glycosaminoglycan (GAG) production. These experiments determined peptide concentrations used in a full-factorial experiment to investigate any interactions. The experiment revealed the BMP peptide as a robust stimulant for GAG production. . © 2013 American Institute of Chemical Engineers.

Expanding the peptide beta-turn in alphagamma hybrid sequences: 12 atom hydrogen bonded helical and hairpin turns.

PubMed

Chatterjee, Sunanda; Vasudev, Prema G; Raghothama, Srinivasarao; Ramakrishnan, Chandrasekharan; Shamala, Narayanaswamy; Balaram, Padmanabhan

2009-04-29

Hybrid peptide segments containing contiguous alpha and gamma amino acid residues can form C(12) hydrogen bonded turns which may be considered as backbone expanded analogues of C(10) (beta-turns) found in alphaalpha segments. Exploration of the regular hydrogen bonded conformations accessible for hybrid alphagamma sequences is facilitated by the use of a stereochemically constrained gamma amino acid residue gabapentin (1-aminomethylcyclohexaneacetic acid, Gpn), in which the two torsion angles about C(gamma)-C(beta) (theta(1)) and C(beta)-C(alpha) (theta(2)) are predominantly restricted to gauche conformations. The crystal structures of the octapeptides Boc-Gpn-Aib-Gpn-Aib-Gpn-Aib-Gpn-Aib-OMe (1) and Boc-Leu-Phe-Val-Aib-Gpn-Leu-Phe-Val-OMe (2) reveal two distinct conformations for the Aib-Gpn segment. Peptide 1 forms a continuous helix over the Aib(2)-Aib(6) segment, while the peptide 2 forms a beta-hairpin structure stabilized by four cross-strand hydrogen bonds with the Aib-Gpn segment forming a nonhelical C(12) turn. The robustness of the helix in peptide 1 in solution is demonstrated by NMR methods. Peptide 2 is conformationally fragile in solution with evidence of beta-hairpin conformations being obtained in methanol. Theoretical calculations permit delineation of the various C(12) hydrogen bonded structures which are energetically feasible in alphagamma and gammaalpha sequences.

Access to site-specific Fc–cRGD peptide conjugates through streamlined expressed protein ligation†

PubMed Central

Frutos, S.; Jordan, J. B.; Bio, M. M.; Muir, T. W.; Thiel, O. R.; Vila-Perelló, M.

2018-01-01

An ideal drug should be highly effective, non-toxic and be delivered by a convenient and painless single dose. We are still far from such optimal treatment but peptides, with their high target selectivity and low toxicity profiles, provide a very attractive platform from which to strive towards it. One of the major limitations of peptide drugs is their high clearance rates, which limit dosage regimen options. Conjugation to antibody Fc domains is a viable strategy to improve peptide stability by increasing their hydrodynamic radius and hijacking the Fc recycling pathway. We report the use of a split-intein based semi-synthetic approach to site-specifically conjugate a synthetic integrin binding peptide to an Fc domain. The strategy described here allows conjugating synthetic peptides to Fc domains, which is not possible via genetic methods, fully maintaining the ability of both the Fc domain and the bioactive peptide to interact with their binding partners. PMID:27722696

Functional characterization on invertebrate and vertebrate tissues of tachykinin peptides from octopus venoms.

PubMed

Ruder, Tim; Ali, Syed Abid; Ormerod, Kiel; Brust, Andreas; Roymanchadi, Mary-Louise; Ventura, Sabatino; Undheim, Eivind A B; Jackson, Timothy N W; Mercier, A Joffre; King, Glenn F; Alewood, Paul F; Fry, Bryan G

2013-09-01

It has been previously shown that octopus venoms contain novel tachykinin peptides that despite being isolated from an invertebrate, contain the motifs characteristic of vertebrate tachykinin peptides rather than being more like conventional invertebrate tachykinin peptides. Therefore, in this study we examined the effect of three variants of octopus venom tachykinin peptides on invertebrate and vertebrate tissues. While there were differential potencies between the three peptides, their relative effects were uniquely consistent between invertebrate and vertebrae tissue assays. The most potent form (OCT-TK-III) was not only the most anionically charged but also was the most structurally stable. These results not only reveal that the interaction of tachykinin peptides is more complex than previous structure-function theories envisioned, but also reinforce the fundamental premise that animal venoms are rich resources of novel bioactive molecules, which are useful investigational ligands and some of which may be useful as lead compounds for drug design and development. Copyright © 2013 Elsevier Inc. All rights reserved.

Biosynthetic engineering of nonribosomal peptide synthetases.

PubMed

Kries, Hajo

2016-09-01

From the evolutionary melting pot of natural product synthetase genes, microorganisms elicit antibiotics, communication tools, and iron scavengers. Chemical biologists manipulate these genes to recreate similarly diverse and potent biological activities not on evolutionary time scales but within months. Enzyme engineering has progressed considerably in recent years and offers new screening, modelling, and design tools for natural product designers. Here, recent advances in enzyme engineering and their application to nonribosomal peptide synthetases are reviewed. Among the nonribosomal peptides that have been subjected to biosynthetic engineering are the antibiotics daptomycin, calcium-dependent antibiotic, and gramicidin S. With these peptides, incorporation of unnatural building blocks and modulation of bioactivities via various structural modifications have been successfully demonstrated. Natural product engineering on the biosynthetic level is not a reliable method yet. However, progress in the understanding and manipulation of biosynthetic pathways may enable the routine production of optimized peptide drugs in the near future. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

Lactoferricin-related peptides with inhibitory effects on ACE-dependent vasoconstriction.

PubMed

Centeno, José M; Burguete, María C; Castelló-Ruiz, María; Enrique, María; Vallés, Salvador; Salom, Juan B; Torregrosa, Germán; Marcos, José F; Alborch, Enrique; Manzanares, Paloma

2006-07-26

A selection of lactoferricin B (LfcinB)-related peptides with an angiotensin I-converting enzyme (ACE) inhibitory effect have been examined using in vitro and ex vivo functional assays. Peptides that were analyzed included a set of sequence-related antimicrobial hexapeptides previously reported and two representative LfcinB-derived peptides. In vitro assays using hippuryl-L-histidyl-L-leucine (HHL) and angiotensin I as substrates allowed us to select two hexapeptides, PACEI32 (Ac-RKWHFW-NH2) and PACEI34 (Ac-RKWLFW-NH2), and also a LfcinB-derived peptide, LfcinB17-31 (Ac-FKCRRWQWRMKKLGA-NH2). Ex vivo functional assays using rabbit carotid arterial segments showed PACEI32 (both D- and L-enantiomers) and LfcinB17-31 have inhibitory effects on ACE-dependent angiotensin I-induced contraction. None of the peptides exhibited in vitro ACE inhibitory activity using bradykinin as the substrate. In conclusion, three bioactive lactoferricin-related peptides exhibit inhibitory effects on both ACE activity and ACE-dependent vasoconstriction with potential to modulate hypertension that deserves further investigation.

Elucidation of Peptide-Directed Palladium Surface Structure for Biologically Tunable Nanocatalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bedford, Nicholas M.; Ramezani-Dakhel, Hadi; Slocik, Joseph M.

Peptide-enabled synthesis of inorganic nanostructures represents an avenue to access catalytic materials with tunable and optimized properties. This is achieved via peptide complexity and programmability that is missing in traditional ligands for catalytic nanomaterials. Unfortunately, there is limited information available to correlate peptide sequence to particle structure and catalytic activity to date. As such, the application of peptide-enabled nanocatalysts remains limited to trial and error approaches. In this paper, a hybrid experimental and computational approach is introduced to systematically elucidate biomolecule-dependent structure/function relationships for peptide-capped Pd nanocatalysts. Synchrotron X-ray techniques were used to uncover substantial particle surface structural disorder, whichmore » was dependent upon the amino acid sequence of the peptide capping ligand. Nanocatalyst configurations were then determined directly from experimental data using reverse Monte Carlo methods and further refined using molecular dynamics simulation, obtaining thermodynamically stable peptide-Pd nanoparticle configurations. Sequence-dependent catalytic property differences for C-C coupling and olefin hydrogenation were then eluddated by identification of the catalytic active sites at the atomic level and quantitative prediction of relative reaction rates. This hybrid methodology provides a clear route to determine peptide-dependent structure/function relationships, enabling the generation of guidelines for catalyst design through rational tailoring of peptide sequences« less

Elucidation of peptide-directed palladium surface structure for biologically tunable nanocatalysts.

PubMed

Bedford, Nicholas M; Ramezani-Dakhel, Hadi; Slocik, Joseph M; Briggs, Beverly D; Ren, Yang; Frenkel, Anatoly I; Petkov, Valeri; Heinz, Hendrik; Naik, Rajesh R; Knecht, Marc R

2015-05-26

Peptide-enabled synthesis of inorganic nanostructures represents an avenue to access catalytic materials with tunable and optimized properties. This is achieved via peptide complexity and programmability that is missing in traditional ligands for catalytic nanomaterials. Unfortunately, there is limited information available to correlate peptide sequence to particle structure and catalytic activity to date. As such, the application of peptide-enabled nanocatalysts remains limited to trial and error approaches. In this paper, a hybrid experimental and computational approach is introduced to systematically elucidate biomolecule-dependent structure/function relationships for peptide-capped Pd nanocatalysts. Synchrotron X-ray techniques were used to uncover substantial particle surface structural disorder, which was dependent upon the amino acid sequence of the peptide capping ligand. Nanocatalyst configurations were then determined directly from experimental data using reverse Monte Carlo methods and further refined using molecular dynamics simulation, obtaining thermodynamically stable peptide-Pd nanoparticle configurations. Sequence-dependent catalytic property differences for C-C coupling and olefin hydrogenation were then elucidated by identification of the catalytic active sites at the atomic level and quantitative prediction of relative reaction rates. This hybrid methodology provides a clear route to determine peptide-dependent structure/function relationships, enabling the generation of guidelines for catalyst design through rational tailoring of peptide sequences.

Short communication: Tryptic β-casein hydrolysate modulates enteric nervous system development in primary culture.

PubMed

Cossais, F; Clawin-Rädecker, I; Lorenzen, P C; Klempt, M

2017-05-01

The intestinal tract of the newborn is particularly sensitive to gastrointestinal disorders, such as infantile diarrhea or necrotizing colitis. Perinatal development of the gut also encompasses the maturation of the enteric nervous system (ENS), a main regulator of intestinal motility and barrier functions. It was recently shown that ENS maturation can be enhanced by nutritional factors to improve intestinal maturation. Bioactivity of milk proteins is often latent, requiring the release of bioactive peptides from inactive native proteins. Several casein-derived hydrolysates presenting immunomodulatory properties have been described recently. Furthermore, accumulating data indicate that milk-derived hydrolysate can enhance gut maturation and enrichment of milk formula with such hydrolysates has recently been proposed. However, the capability of milk-derived bioactive hydrolysate to target ENS maturation has not been analyzed so far. We, therefore, investigated the potential of a recently described tryptic β-casein hydrolysate to modulate ENS growth parameters in an in vitro model of rat primary culture of ENS. Rat primary cultures of ENS were incubated with a bioactive tryptic β-casein hydrolysate and compared with untreated controls or to cultures treated with native β-casein or a Prolyve β-casein hydrolysate (Lyven, Colombelles, France). Differentiation of enteric neurons and enteric glial cells, and establishment of enteric neural network were analyzed using immunohistochemistry and quantitative PCR. Effect of tryptic β-casein hydrolysate on bone morphogenetic proteins (BMP)/Smad pathway, an essential regulator of ENS development, was further assessed using quantitative PCR and immunochemistry. Tryptic β-casein hydrolysate stimulated neurite outgrowth and simultaneously modulated the formation of enteric ganglia-like structures, whereas native β-casein or Prolyve β-casein hydrolysate did not. Additionally, treatment with tryptic bioactive β-casein hydrolysate increased the expression of the glial marker glial fibrillary acidic protein and induced profound modifications of enteric glial cells morphology. Finally, expression of BMP2 and BMP4 and activation of Smad1/5 was altered after treatment with tryptic bioactive β-casein hydrolysate. Our data suggests that this milk-derived bioactive hydrolysate modulates ENS maturation through the regulation of BMP/Smad-signaling pathway. This study supports the need for further investigation on the influence of milk-derived bioactive peptides on ENS and intestinal maturation in vivo. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Enzymatic hybridization of α-lipoic acid with bioactive compounds in ionic solvents.

PubMed

Papadopoulou, Athena A; Katsoura, Maria H; Chatzikonstantinou, Alexandra; Kyriakou, Eleni; Polydera, Angeliki C; Tzakos, Andreas G; Stamatis, Haralambos

2013-05-01

The lipase-catalyzed molecular hybridization of α-lipoic acid (LA) with bioactive compounds pyridoxine, tyrosol and tyramine was performed in ionic solvents and deep eutectic solvents. The biocatalytic reactions were catalyzed by Candida antarctica lipase B immobilized onto various functionalized multi-walled carbon nanotubes (f-CNTs-CaLB), as well as by commercial Novozym 435. The use of f-CNTs-CaLB leads, in most cases, to higher conversion yields as compared to Novozym 435. The nature and ion composition of ionic solvents affect the performance of the biocatalytic process. The highest conversion yield was observed in (mtoa)NTf2. The high enzyme stability and the relatively low solubility of substrates in specific media account for the improved biocatalytic synthesis of molecular hybrids of LA. Principal component analysis was used to screen for potential lipoxygenase inhibitors. In vitro studies showed that the synthesized compounds exhibit up to 10-fold increased inhibitory activity on lipoxygenase mediated lipid peroxidation as compared to parent molecules. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pore forming properties of cecropin-melittin hybrid peptide in a natural membrane.

PubMed

Milani, Alberto; Benedusi, Mascia; Aquila, Marco; Rispoli, Giorgio

2009-12-11

The pore forming properties of synthetic cecropin-melittin hybrid peptide (Acetyl-KWKLFKKIGAVLKVL-CONH(2); CM15) were investigated by using photoreceptor rod outer segments (OS) isolated from frog retinae obtained by using the whole-cell configuration of the patch-clamp technique. CM15 was applied (and removed) to (from) the OS in approximately 50 ms with a computer-controlled microperfusion system. Once the main OS endogenous conductance was blocked with light, the OS membrane resistance was >or=1 G Omega, allowing high resolution, low-noise recordings. Different to alamethicines, CM15 produced voltage-independent membrane permeabilisation, repetitive peptide application caused a progressive permeabilisation increase, and no single-channel events were detected at low peptide concentrations. Collectively, these results indicate a toroidal mechanism of pore formation by CM15.

Characterization of the Two CART Genes (CART1 and CART2) in Chickens (Gallus gallus)

PubMed Central

Huang, Long; Li, Juan; Wang, Yajun

2015-01-01

Cocaine- and amphetamine-regulated transcript (CART) peptide is implicated in the control of avian energy balance, however, the structure and expression of CART gene(s) remains largely unknown in birds. Here, we cloned and characterized two CART genes (named cCART1 and cCART2) in chickens. The cloned cCART1 is predicted to generate two bioactive peptides, cCART1(42-89) and cCART1(49-89), which share high amino acid sequence identity (94-98%) with their mammalian counterparts, while the novel cCART2 may produce a bioactive peptide cCART2(51-91) with 59% identity to cCART1. Interestingly, quantitative RT-PCR revealed that cCART1 is predominantly expressed in the anterior pituitary and less abundantly in the hypothalamus. In accordance with this finding, cCART1 peptide was easily detected in the anterior pituitary by Western blot, and its secretion from chick pituitaries incubated in vitro was enhanced by ionomycin and forskolin treatment, indicating that cCART1 is a novel peptide hormone produced by the anterior pituitary. Moreover, cCART1 mRNA expression in both the pituitary and hypothalamus is down-regulated by 48-h fasting, suggesting its expression is affected by energy status. Unlike cCART1, cCART2 is only weakly expressed in most tissues examined by RT-PCR, implying a less significant role of cCART2 in chickens. As in chickens, 2 or more CART genes, likely generated by gene and genome duplication event(s), were also identified in other non-mammalian vertebrate species including coelacanth. Collectively, the identification and characterization of CART genes in birds helps to uncover the roles of CART peptide(s) in vertebrates and provides clues to the evolutionary history of vertebrate CART genes. PMID:25992897

Metagenomic Analysis of the Sponge Discodermia Reveals the Production of the Cyanobacterial Natural Product Kasumigamide by 'Entotheonella'.

PubMed

Nakashima, Yu; Egami, Yoko; Kimura, Miki; Wakimoto, Toshiyuki; Abe, Ikuro

2016-01-01

Sponge metagenomes are a useful platform to mine cryptic biosynthetic gene clusters responsible for production of natural products involved in the sponge-microbe association. Since numerous sponge-derived bioactive metabolites are biosynthesized by the symbiotic bacteria, this strategy may concurrently reveal sponge-symbiont produced compounds. Accordingly, a metagenomic analysis of the Japanese marine sponge Discodermia calyx has resulted in the identification of a hybrid type I polyketide synthase-nonribosomal peptide synthetase gene (kas). Bioinformatic analysis of the gene product suggested its involvement in the biosynthesis of kasumigamide, a tetrapeptide originally isolated from freshwater free-living cyanobacterium Microcystis aeruginosa NIES-87. Subsequent investigation of the sponge metabolic profile revealed the presence of kasumigamide in the sponge extract. The kasumigamide producing bacterium was identified as an 'Entotheonella' sp. Moreover, an in silico analysis of kas gene homologs uncovered the presence of kas family genes in two additional bacteria from different phyla. The production of kasumigamide by distantly related multiple bacterial strains implicates horizontal gene transfer and raises the potential for a wider distribution across other bacterial groups.