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Sample records for oral farnesyl transferase

  1. Farnesyl transferase inhibitors as anticancer agents.

    PubMed

    Haluska, P; Dy, G K; Adjei, A A

    2002-09-01

    Protein farnesylation catalysed by the enzyme farnesyl protein transferase involves the addition of a 15-carbon farnesyl group to conserved amino acid residues at the carboxyl terminus of certain proteins. Protein substrates of farnesyl transferase include several G-proteins, which are critical intermediates of cell signalling and cytoskeletal organisation such as Ras, Rho, PxF and lamins A and B. Activated Ras proteins trigger a cascade of phosphorylation events through sequential activation of the PI3 kinase/AKT pathway, which is critical for cell survival, and the Raf/Mek/Erk kinase pathway that has been implicated in cell proliferation. Ras mutations which encode for constitutively activated proteins are found in 30% of human cancers. Because farnesylation of Ras is required for its transforming and proliferative activity, the farnesyl protein transferase inhibitors were designed as anticancer agents to abrogate Ras function. However, current evidence suggests that the anticancer activity of the farnesyl transferase inhibitors may not be simply due to Ras inhibition. This review will discuss available clinical data on three of these agents that are currently undergoing clinical trials.

  2. Effects of SCH 59228, an orally bioavailable farnesyl protein transferase inhibitor, on the growth of oncogene-transformed fibroblasts and a human colon carcinoma xenograft in nude mice.

    PubMed

    Liu, M; Bryant, M S; Chen, J; Lee, S; Yaremko, B; Li, Z; Dell, J; Lipari, P; Malkowski, M; Prioli, N; Rossman, R R; Korfmacher, W A; Nomeir, A A; Lin, C C; Mallams, A K; Doll, R J; Catino, J J; Girijavallabhan, V M; Kirschmeier, P; Bishop, W R

    1999-01-01

    The products of the Ha-, Ki-, and N-ras proto-oncogenes comprise a family of 21 kDa guanine nucleotide-binding proteins which play a crucial role in growth factor signal transduction and in the control of cellular proliferation and differentiation. Activating mutations in the ras oncogenes occur in a wide variety of human tumors. Ras proteins undergo a series of posttranslational processing events. The first modification is addition of the 15-carbon isoprene, farnesyl, to a Cys residue near the carboxy-terminus of Ras. Prenylation allows the Ras oncoprotein to localize to the plasma membrane where it can initiate downstream signalling events leading to cellular transformation. Inhibitors of the enzyme which catalyzes this step, farnesyl protein transferase (FPT), are a potential class of novel anticancer drugs which interfere with Ras function. SCH 59228 is a tricyclic FPT inhibitor which inhibits the farnesylation of purified Ha-Ras with an IC50 of 95 nM and blocks the processing of Ha-Ras in Cos cells with an IC50 of 0.6 microM. SCH 59228 has favorable pharmacokinetic properties upon oral dosing in nude mice. The in vivo efficacy of SCH 59228 was evaluated using a panel of tumor models grown in nude mice. These included several rodent fibroblast lines expressing mutationally-activated (val12) forms of the Ha-Ras oncogene. In some cases, these proteins contain their native C-terminal sequence (CVLS) which directs farnesylation. In one model, the C-terminal sequence was altered to CVLL, making the expressed protein a substrate for a distinct prenyl transferase, geranylgeranyl protein transferase-1. When dosed orally at 10 and 50 mg/kg (four times a day, 7 days a week) SCH 59228 significantly inhibited tumor growth of cells expressing farnesylated Ha-Ras in a dose-dependent manner; over 90% growth inhibition was observed at the 50 mg/kg dose. Tumor growth of cells expressing the geranylgeranylated form of Ha-Ras was less potently inhibited. Growth of tumors derived

  3. Characterization of the antitumor effects of the selective farnesyl protein transferase inhibitor R115777 in vivo and in vitro.

    PubMed

    End, D W; Smets, G; Todd, A V; Applegate, T L; Fuery, C J; Angibaud, P; Venet, M; Sanz, G; Poignet, H; Skrzat, S; Devine, A; Wouters, W; Bowden, C

    2001-01-01

    R115777 [(B)-6-[amino(4-chlorophenyl)(1-methyl-1H-imidazol-5-yl)-methyl]-4-(3-chlorophenyl)-1-methyl-2(1H)-quinolinone] is a potent and selective inhibitor of farnesyl protein transferase with significant antitumor effects in vivo subsequent to oral administration in mice. In vitro, using isolated human farnesyl protein transferase, R115777 competitively inhibited the farnesylation of lamin B and K-RasB peptide substrates, with IC50s of 0.86 nM and 7.9 nM, respectively. In a panel of 53 human tumor cell lines tested for growth inhibition, approximately 75% were found to be sensitive to R115777. The majority of sensitive cell lines had a wild-type ras gene. Tumor cell lines bearing H-ras or N-ras mutations were among the most sensitive of the cell lines tested, with responses observed at nanomolar concentrations of R115777. Tumor cell lines bearing mutant K-ras genes required higher concentrations for inhibition of cell growth, with 50% of the cell lines resistant to R115777 up to concentrations of 500 nM. Inhibition of H-Ras, N-Ras, and lamin B protein processing was observed at concentrations of R115777 that inhibited cell proliferation. However, inhibition of K-RasB protein-processing could not be detected. Oral administration b.i.d. of R115777 to nude mice bearing s.c. tumors at doses ranging from 6.25-100 mg/kg inhibited the growth of tumors bearing mutant H-ras, mutant K-ras, and wild-type ras genes. Histological evaluations revealed heterogeneity in tumor responses to R115777. In LoVo human colon tumors, treatment with R115777 produced a prominent antiangiogenic response. In CAPAN-2 human pancreatic tumors, an antiproilferative response predominated, whereas in C32 human melanoma, marked induction of apoptosis was observed. The heterogeneity of histological changes associated with antitumor effects suggested that R115777, and possibly farnesyl protein transferase inhibitors as a class, alter processes of transformation related to tumor-host interactions in

  4. Farnesyl protein transferase inhibitors targeting the catalytic zinc for enhanced binding.

    PubMed

    Njoroge, F George; Vibulbhan, Bancha; Pinto, Patrick; Strickland, Corey; Kirschmeier, Paul; Bishop, W Robert; Girijavallabhan, V

    2004-12-06

    Successful efforts to make farnesyl transferase (FT) inhibitors with appropriately tethered ligands designed to interact with a catalytic zinc that exist in the enzyme have been realized. Thus, by introducing either a pyridylmethylamino or propylaminolimidazole amide moieties off the 2-position of the piperidine ring, FT inhibitors with activities in the picomolar range have been achieved as exemplified by compounds 12a and 12b. An X-ray structure of 11b bound to FT shows the enhanced activity is a result of interacting with the active-site zinc.

  5. Farnesyl transferase inhibitors: a major breakthrough in anticancer therapy? Naples, 12 April 2002.

    PubMed

    Caponigro, Francesco

    2002-09-01

    An international meeting focused on farnesyl transferase inhibitors (FTIs) was held in Naples on 12 April 2002 and represented an excellent occasion to gather most of the clinicians who are involved in clinical trials with this class of new compounds. Oncogene mutations of the gene occur in approximately 30% of all human cancers and may have prognostic significance. Ras protein is normally synthesized as pro-Ras, which undergoes a number of post-translational modifications, among which farnesylation. Processed Ras proteins localize to the inner surface of the plasma membrane, and function as a molecular switch that cycles between an inactive and an active form. When in its active form, either because of the binding of an external ligand or because of its constitutive activation, Ras activates several downstream effectors, such as Raf-1, Rac, Rho and phospahtidylinositol-3 kinase, which mediate important cellular functions, such as proliferation, cytoskeletal organization and others. Interruption of the Ras signaling pathway can be basically achieved in three ways, i.e. inhibition of Ras protein expression through antisense oligonucleotides, prevention of Ras membrane localization and inhibition of Ras downstream effectors. SCH 66336 (lonafarnib; Sarasar), a tricyclic orally active FTI, has been the first of these compounds to undergo clinical development. The toxicity profile observed in all completed phase I/II trials has been fairly similar, since gastrointestinal tract toxicity (nausea, vomiting and diarrhea) and fatigue have generally qualified as dose-limiting toxicity (DLT). One objective response in a patient with pretreated non-small cell lung cancer (NSCLC) was observed. Based on preclinical evidence of synergism between lonafarnib and other anticancer agents, combination studies have been started. In particular, lonafarnib has been combined both with gemcitabine and with paclitaxel in phase I studies. Nausea, vomiting, diarrhea and myelosuppression

  6. Synthesis and evaluation of a novel series of farnesyl protein transferase inhibitors as non-peptidic CAAX tetrapeptide analogues.

    PubMed

    Perez, Michel; Maraval, Catherine; Dumond, Stephan; Lamothe, Marie; Schambel, Philippe; Etiévant, Chantal; Hill, Bridget

    2003-04-17

    A novel series of compounds, derived from 4-amino-phenyl piperazine, has been designed to selectively inhibit farnesyl protein transferase (FPTase) as CAAX tetrapeptide analogues. Certain of these compounds were shown to possess low nanomolar inhibitory activity both against the isolated enzyme and in cultured cells.

  7. Novel derivatives of aclacinomycin A block cancer cell migration through inhibition of farnesyl transferase.

    PubMed

    Magi, Shigeyuki; Shitara, Tetsuo; Takemoto, Yasushi; Sawada, Masato; Kitagawa, Mitsuhiro; Tashiro, Etsu; Takahashi, Yoshikazu; Imoto, Masaya

    2013-03-01

    In the course of screening for an inhibitor of farnesyl transferase (FTase), we identified two compounds, N-benzyl-aclacinomycin A (ACM) and N-allyl-ACM, which are new derivatives of ACM. N-benzyl-ACM and N-allyl-ACM inhibited FTase activity with IC50 values of 0.86 and 2.93 μM, respectively. Not only ACM but also C-10 epimers of each ACM derivative failed to inhibit FTase. The inhibition of FTase by N-benzyl-ACM and N-allyl-ACM seems to be specific, because these two compounds did not inhibit geranylgeranyltransferase or geranylgeranyl pyrophosphate (GGPP) synthase up to 100 μM. In cultured A431 cells, N-benzyl-ACM and N-allyl-ACM also blocked both the membrane localization of H-Ras and activation of the H-Ras-dependent PI3K/Akt pathway. In addition, they inhibited epidermal growth factor (EGF)-induced migration of A431 cells. Thus, N-benzyl-ACM and N-allyl-ACM inhibited EGF-induced migration of A431 cells by inhibiting the farnesylation of H-Ras and subsequent H-Ras-dependent activation of the PI3K/Akt pathway.

  8. Molecular docking and simulation of Curcumin with Geranylgeranyl Transferase1 (GGTase1) and Farnesyl Transferase (FTase).

    PubMed

    Subramani, Parasuraman Aiya; Narala, Venkata Ramireddy; Michael, R Dinakaran; Lomada, Dakshayani; Reddy, Madhava C

    2015-01-01

    Protein prenylation is a posttranslational modification that is indispensable for translocation of membrane GTPases like Ras, Rho, Ras etc. Proteins of Ras family undergo farnesylation by FTase while Rho family goes through geranylgeranylation by GGTase1. There is only an infinitesimal difference in signal recognition between FTase and GGTase1. FTase inhibitors mostly end up selecting the cells with mutated Ras proteins that have acquired affinity towards GGTase1 in cancer microcosms. Therefore, it is of interest to identify GGTase1 and FTase dual inhibitors using the docking tool AutoDock Vina. Docking data show that curcumin (from turmeric) has higher binding affinity to GGTase1 than that of established peptidomimetic GGTase1 inhibitors (GGTI) such as GGTI-297, GGTI-298, CHEMBL525185. Curcumin also interacts with FTase with binding energy comparable to co-crystalized compound 2-[3-(3-ethyl-1-methyl-2-oxo-azepan-3-yl)-phenoxy]-4-[1-amino-1-(1-methyl-1h-imidizol-5-yl)-ethyl]-benzonitrile (BNE). The docked complex was further simulated for 10 ns using molecular dynamics simulation for stability. Thus, the molecular basis for curcumin binding to GGTase1 and FTase is reported.

  9. Aborted Autophagy and Nonapoptotic Death Induced by Farnesyl Transferase Inhibitor and LovastatinS⃞

    PubMed Central

    Wojtkowiak, Jonathan W.; Sane, Komal M.; Kleinman, Miriam; Sloane, Bonnie F.; Reiners, John J.

    2011-01-01

    Exposure of the human malignant peripheral nerve sheath tumor cell lines STS-26T, ST88-14, and NF90-8 to nanomolar concentrations of both lovastatin and farnesyl transferase inhibitor (FTI)-1 but not to either drug alone induced cell death. ST88-14 and NF90-8 cells underwent apoptosis, yet dying STS-26T cells did not. FTI-1 cotreatment induced a strong and sustained autophagic response as indicated by analyses of microtubule-associated protein-1 light chain 3 (LC3)-II accumulation in STS-26T cultures. Extensive colocalization of LC3-positive punctate spots was observed with both lysosome-associated membrane protein (LAMP)-1 and LAMP-2 (markers of late endosomes/lysosomes) in solvent or FTI-1 or lovastatin-treated STS-26T cultures but very little colocalization in lovastatin/FTI-1-cotreated cultures. The absence of colocalization in the cotreatment protocol correlated with loss of LAMP-2 expression. Autophagic flux studies indicated that lovastatin/FTI-1 cotreatment inhibited the completion of the autophagic program. In contrast, rapamycin induced an autophagic response that was associated with cytostasis but maintenance of viability. These studies indicate that cotreatment of STS-26T cells with lovastatin and FTI-1 induces an abortive autophagic program and nonapoptotic cell death. PMID:21228063

  10. Protein isoprenylation regulates osteogenic differentiation of mesenchymal stem cells: effect of alendronate, and farnesyl and geranylgeranyl transferase inhibitors

    PubMed Central

    Duque, G; Vidal, C; Rivas, D

    2011-01-01

    BACKGROUND AND PURPOSE Protein isoprenylation is an important step in the intracellular signalling pathway conducting cell growth and differentiation. In bone, protein isoprenylation is required for osteoclast differentiation and activation. However, its role in osteoblast differentiation and function remains unknown. In this study, we assessed the role of protein isoprenylation in osteoblastogenesis in a model of mesenchymal stem cells (MSC) differentiation. EXPERIMENTAL APPROACH We tested the effect of an inhibitor of farnesylation [farnesyl transferase inhibitor-277 (FTI-277)] and one of geranylgeranylation [geranylgeranyltransferase inhibitor-298 (GGTI-298)] on osteoblast differentiating MSC. In addition, we tested the effect of alendronate on protein isoprenylation in this model either alone or in combination with other inhibitors of isoprenylation. KEY RESULTS Initially, we found that levels of unfarnesylated proteins (prelamin A and HDJ-2) increased after treatment with FTI-277 concomitantly affecting osteoblastogenesis and increasing nuclear morphological changes without affecting cell survival. Furthermore, inhibition of geranylgeranylation by GGTI-298 alone increased osteoblastogenesis. This effect was enhanced by the combination of GGTI-298 and alendronate in the osteogenic media. CONCLUSIONS AND IMPLICATIONS Our data indicate that both farnesylation and geranylgeranylation play a role in osteoblastogenesis. In addition, a new mechanism of action for alendronate on protein isoprenylation in osteogenic differentiating MSC in vitro was found. In conclusion, protein isoprenylation is an important component of the osteoblast differentiation process that could constitute a new therapeutic target for osteoporosis in the future. PMID:21077849

  11. A protein-farnesyl transferase inhibitor interferes with the serum-induced conversion of Candida albicans from a cellular yeast form to a filamentous form.

    PubMed

    McGeady, Paul; Logan, David A; Wansley, Daniel L

    2002-07-16

    A commercially available, cell permeable, protein-farnesyl transferase inhibitor interfered with the serum-induced morphological change in Candida albicans from a cellular yeast form to a filamentous form. The inhibitor has a negligible effect on the growth of C. albicans cells in the cellular yeast form, at the levels used to interfere with the morphological change. Conversion of C. albicans from the yeast form to filamentous form is associated with pathogenicity and hence protein-farnesyl transferase inhibitors are potentially of therapeutic value against C. albicans infection.

  12. From pure FPP to mixed FPP and CAAX competitive inhibitors of farnesyl protein transferase.

    PubMed

    Lannuzel, Marc; Lamothe, Marie; Schambel, Philippe; Etiévant, Chantal; Hill, Bridget; Perez, Michel

    2003-04-17

    Starting from a FPP analogue with nanomolar inhibitory activity against isolated FPTase, yet lacking activity in cellular assays, structural modifications were performed to enhance cellular activity by removing all acidic functionalities. Overall, these changes resulted in the transformation of a pure FPP to a mixed FPP and CAAX competitive inhibitor with nanomolar activity on isolated FPTase and micromolar inhibitory activity in the farnesylation of H-Ras in cultured DLD-1 cells.

  13. Proteomic identification of heat shock protein 70 as a candidate target for enhancing apoptosis induced by farnesyl transferase inhibitor.

    PubMed

    Hu, Wei; Wu, WeiGuo; Verschraegen, Claire F; Chen, Ling; Mao, Li; Yeung, Sai-Ching Jim; Kudelka, Andrzej P; Freedman, Ralph S; Kavanagh, John J

    2003-10-01

    Farnesyl transferase inhibitors (FTIs) are novel antitumor drugs with clinical activity. FTIs inhibit cell growth not only by preventing direct Ras farnesylation but also through a Ras-independent pathway. Proteomics has been shown to be a powerful tool to monitor and analyze molecular networks and fluxes within the living cells and to identify the proteins that participate in these networks upon perturbation of the cellular environment. To observe early and dynamic protein changes in the cellular response to FTI in ovarian cancer cells, total proteins were extracted from 2774 cells treated or not with 10 microM manumycin, an FTI, for 3, 6 and 16 h. The proteins in the cells that were differentially expressed following treatment with manumycin for 3, 6 and 16 h were noted by two-dimensional electrophoresis and further identified by peptide mass fingerprinting as stress proteins. Both heat shock protein 70 (HSP70) and altered HSP70 were significantly up-regulated as early as 16 h in 2774 cells after exposure to manumycin. Since HSP70 plays an important role in protecting cells under stress, we treated the 2774 cells with the HSP inhibitor quercetin in combination with FTI. Quercetin dramatically enhanced the manumycin-mediated apoptosis in 2774 cells. Inducible HSP70 by manumycin in surviving ovarian cancer cells was also inhibited by quercetin as demonstrated by enzyme-linked immunosorbent assay. The inhibition of HSP70 by quercetin was correlated with enhancement of manumycin-induced mediated apoptosis in 2774 cells. The inhibition of HSP70 by 50 microM quercetin was also correlated with a decreased expression of procaspase-3 and enhancement of specific cleavage of poly (ADP-ribose) polymerase into apoptotic fragment in 2774 cells treated with manumycin. The interaction between the HSP70 inhibitor and FTI confirms the functional significance of the up-regulation of HSP70 as a protective mechanism against FTI-induced apoptosis and provides the framework for

  14. Breast Cancer Stem Cells Survive Periods of Farnesyl-Transferase Inhibitor-Induced Dormancy by Undergoing Autophagy

    PubMed Central

    Chaterjee, Moumita; van Golen, Kenneth L.

    2011-01-01

    A cancer stem cell has been defined as a cell within a tumor that possesses the capacity to self-renew and to cause the heterogeneous lineages of cancer cells that comprise the tumor. These tumor-forming cells could hypothetically originate from stem, progenitor, or differentiated cells. Previously, we have shown that breast cancer cells with low metastatic potential can be induced into a reversible state of dormancy by farnesyl transferase inhibitors (FTIs). Dormancy was induced by changes in RhoA and RhoC GTPases. Specifically, RhoA was found to be hypoactivated while RhoC was hyperactivated. In the current study we demonstrate that these dormant cells also express certain known stem cell markers such as aldehyde dehydrogenase I (ALDHI) and cluster of differentiation 44 (CD44). We also show that autophagy markers Atg5, Atg12, and LC3-B are expressed in these dormant stem cell-like breast cancer cells. Inhibiting autophagy by inhibitor 3-methyladenine (3-MA) blocked the process of autophagy reversing the dormant phenotype. Further, we show that c-jun NH2 terminal kinase (JNK/SAPK) is upregulated in these dormant stem cell-like breast cancer cells and is responsible for increasing autophagy. PMID:22046561

  15. Farnesyl Transferase Expression Determines Clinical Response to the Docetaxel-Lonafarnib Combination in Patients with Advanced Malignancies

    PubMed Central

    Kauh, John; Chanel-Vos, Chantal; Escuin, Daniel; Fanucchi, Michael P; Harvey, R. Donald; Saba, Nabil; Shin, Dong M.; Gal, Anthony; Pan, Lin; Kutner, Michael; Ramalingam, Suresh S.; Bender, Laura; Marcus, Adam; Giannakakou, Paraskevi; Khuri, Fadlo R.

    2011-01-01

    Background Lonafarnib (LNF) is a protein farnesyl transferase (FTase) inhibitor that has shown synergistic activity with taxanes in preclinical models and early stage clinical trials. Preclinical findings suggested tubulin acetylation and FTase expression levels may be important determinants of drug sensitivity that would help identify patient populations more likely to benefit from this regimen. This pilot study evaluated the biological effects of LNF and docetaxel (DTX) combination therapy in refractory solid tumors by comparing pre- and post-treatment tumor biopsies. Methods Patients with histologically-confirmed locally advanced or metastatic solid malignancies refractory to standard therapies or with no effective therapies available were eligible. Patients were randomized to one of four dosing cohorts: (1) 30mg/m2, 100mg, (2) 36mg/m2, 100mg, (3) 30mg/m2, 150mg, or (4) 36mg/m2, 150mg of DTX IV weekly, LNF PO BID, respectively. Results Of the 38 patients enrolled, 36 were treated, and 29 were evaluable for toxicity and response assessment. The combination of LNF and DTX was tolerated in all cohorts with the exception of a 28% incidence of grade 3/4 diarrhea which was manageable with aggressive anti-diarrheal regimens. Seven patients derived clinically meaningful benefit from this combination treatment; these patients had significantly lower basal FTase-beta mRNA expression levels than the mean study population level (p<0.05). Correlation of clinical benefit with tubulin acetylation content as well as basal acetyl-tubulin content were evaluated. However, no significant correlation was found. Conclusions Despite the small number of patients, these findings support our preclinical mechanistic studies and warrant further clinical investigations using FTase-beta mRNA expression as a potential predictive biomarker to select for an enriched patient population to study the effects of taxane and FTase inhibitor combination therapies. PMID:21365629

  16. Targeting farnesyl-transferase as a novel therapeutic strategy for mevalonate kinase deficiency: in vitro and in vivo approaches.

    PubMed

    De Leo, Luigina; Marcuzzi, Annalisa; Decorti, Giuliana; Tommasini, Alberto; Crovella, Sergio; Pontillo, Alessandra

    2010-06-01

    Mevalonate kinase deficiency (MKD) is a rare inborn auto-inflammatory disease due to the impairment of the pathway for the biosynthesis of cholesterol and non-sterol isoprenoids. The shortage of isoprenoids compounds and in particular of geranylgeranylpyrophosphate (GGPP) was recently associated to the MKD characteristic inflammatory attacks. The aim of this study is to demonstrate that the normalization of the mevalonate pathway intermediates levels and in particular of GGPP, through the specific inhibition of farnesyl-transferase (FT) with Manumycin A could ameliorate the inflammatory phenotype of MKD patients. The effect of Manumycin A was first evaluated in MKD mouse and cellular models, chemically obtained using the aminobisphosphonate alendronate (ALD), and then in monocytes isolated from 2 MKD patients. Our findings were compared to those obtained by using natural exogenous isoprenoids (NEIs). Manumycin A was able to significantly reduce the inflammatory marker serum amyloid A in ALD-treated Balb/c mice, as well as IL-1 beta secretion in ALD-monocytes and in MKD patients. These results clearly showed that, through the inhibition of FT, an increased number of mevalonate pathway intermediates could be redirected towards the synthesis of GGPP diminishing the inflammatory response. The importance in limiting the shortage of GGPP was emphasized by the anti-inflammatory effect of NEIs that, due to their biochemical structure, can enter the MKD pathway. In conclusion, manumycin A, as well as NEIs, showed anti-inflammatory effect in MKD models and especially in MKD-monocytes, suggesting novel approaches in the treatment of MKD, an orphan disease without any efficacious treatment currently available.

  17. Nf1-deficient mouse Schwann cells are angiogenic and invasive and can be induced to hyperproliferate: reversion of some phenotypes by an inhibitor of farnesyl protein transferase.

    PubMed Central

    Kim, H A; Ling, B; Ratner, N

    1997-01-01

    We have developed a potential model of Schwann cell tumor formation in neurofibromatosis type 1 (NF1). We show that mouse Schwann cells heterozygous or null at Nf1 display angiogenic and invasive properties, mimicking the behavior of Schwann cells from human neurofibromas. Mutations at Nf1 are insufficient to promote Schwann cell hyperplasia. Here we show that Schwann cell hyperplasia can be induced by protein kinase A activation in mutant cells. Removal of serum from the culture medium also stimulates hyperplasia, but only in some mutant cells. After serum removal, clones of hyperproliferating Schwann cells lose contact with axons in vitro, develop growth factor-independent proliferation, and exhibit decreased expression of the cell differentiation marker P0 protein; hyperproliferating cells develop after a 1-week lag in Schwann cells heterozygous at Nf1. The experiments suggest that events subsequent to Nf1 mutations are required for development of Schwann cell hyperplasia. Finally, an anti-Ras farnesyl protein transferase inhibitor greatly diminished both clone formation and hyperproliferation of null mutant cells, but not invasion; farnesyl transferase inhibitors could be useful in treating benign manifestations of NF1. PMID:9001241

  18. Transformation by HrasG12V is Consistently Associated with Mutant Allele Copy Gains and is Reversed by Farnesyl Transferase Inhibition

    PubMed Central

    Chen, Xu; Makarewicz, Jacek M.; Knauf, Jeffrey A.; Johnson, Linda K.; Fagin, James A.

    2014-01-01

    RAS-driven malignancies remain a major therapeutic challenge. The two-stage 7,12-dimethylbenz(a)anthracene (DMBA)/12-o-tetradecanoylphorbol-13-acetate (TPA) model of mouse skin carcinogenesis has been used to study mechanisms of epithelial tumor development by oncogenic Hras. We used mice with a HrasG12V knock-in allele to elucidate the early events after Hras activation, and to evaluate the therapeutic effectiveness of farnesyltransferase (FTI) inhibition. Treatment of Caggs-Cre/FR-HrasG12V mice with TPA alone was sufficient to trigger papilloma development with shorter latency and a ~10-fold greater tumor burden than DMBA/TPA-treated WT controls. HrasG12V allele copy number was increased in all papillomas induced by TPA. DMBA/TPA treatment of HrasG12V knock-in mice induced an even greater incidence of papillomas, which either harbored HrasG12V amplification, or developed a HrasQ61L mutation in the second allele. Laser-capture microdissection of normal skin, hyperplastic skin and papillomas showed that amplification occurred only at the papilloma stage. HRAS mutant allelic imbalance was also observed in human cancer cell lines, consistent with a requirement for augmented oncogenic HRAS signaling for tumor development. The FTI SCH66336 blocks HRAS farnesylation and delocalizes it from the plasma membrane. NRAS and KRAS are not affected as they are alternatively prenylated. When tested in lines harboring HRAS, NRAS or KRAS mutations, SCH66336 delocalized, inhibited signaling and preferentially inhibited growth only of HRAS-mutant lines. Treatment with SCH66336 also induced near-complete regression of papillomas of TPA-treated HrasG12V knock-in mice. These data suggest that farnesyl transferase inhibitors should be reevaluated as targeted agents for human HRAS-driven cancers, such as those of bladder, thyroid and other epithelial lineages. PMID:24240680

  19. Pamidronate, farnesyl transferase, and geranylgeranyl transferase-I inhibitors affects cell proliferation, apoptosis, and OPG/RANKL mRNA expression in stromal cells of giant cell tumor of bone.

    PubMed

    Lau, Carol P Y; Huang, Lin; Tsui, Stephen K W; Ng, Patrick K S; Leung, Pui-Yin; Kumta, Shekhar M

    2011-03-01

    Giant cell tumor (GCT) is the most common nonmalignant primary bone tumor reported in Hong Kong. It usually affects young adults between the ages of 20 and 40. This tumor is well known for its potential to recur following treatment. To date no effective adjuvant therapy exists for GCT. Our project aimed to study the effects of pamidronate (PAM), farnesyl transferase inhibitor (FTI-277), geranylgeranyl transferase inhibitor (GGTI-298), and their combinations on GCT stromal cells (SC). Individual treatment with PAM, FTI-277, and GGTI-298, inhibited the cell viability and proliferation of GCT SC in a dose-dependent way. Combination of FTI-277 with GGTI-298 caused synergistic effects in reducing cell viability, and its combination index was 0.49, indicating a strong synergism. Moreover, the combination of FTI-277 with GGTI-298 synergistically enhanced cell apoptosis and activated caspase-3/7, -8, and -9 activities. PAM induced cell-cycle arrest at the S-phase. The combination of PAM with GGTI-298 significantly increased OPG/RANKL mRNA ratio and activated caspase-3/7 activity. Our findings support that the combination of bisphosphonates with GGTIs or FTIs with GGTIs may be used as potential adjuvants in the treatment of GCT of bone. Copyright © 2010 Orthopaedic Research Society.

  20. Farnesyl transferase inhibitor FTI-277 inhibits breast cell invasion and migration by blocking H-Ras activation.

    PubMed

    Lee, Kyung Hun; Koh, Minsoo; Moon, Aree

    2016-09-01

    Hyperactive Ras promotes proliferation and malignant phenotypic conversion of cells in cancer. Ras protein must be associated with cellular membranes for its oncogenic activities through post-translational modifications, including farnesylation. Farnesyltransferase (FTase) is essential for H-Ras membrane targeting, and H-Ras, but not N-Ras, has been demonstrated to cause an invasive phenotype in MCF10A breast epithelial cells. In the present study, it was observed that an FTase inhibitor (FTI), FTI-277, blocked epidermal growth factor (EGF)-induced H-Ras activation, but not N-Ras activation in MDA-MB-231 cells, which express wild-type H-Ras and N-Ras. FTI-277 exerted a more potent inhibitory effect on the proliferation of H-Ras-MCF10A cells and Hs578T breast cancer cells expressing an active mutant of H-Ras than that of MDA-MB-231 cells. The invasive/migratory phenotypes of the H-Ras-MCF10A and Hs578T cells were effectively inhibited by FTI-277 treatment. By contrast, FTI-277 did not affect the invasive/migratory phenotypes of MDA-MB-231 cells. However, the EGF-induced invasion of MDA-MB-231 cells was decreased by FTI-277, implicating that FTI-277 inhibits breast cell invasion and migration by blocking H-Ras activation. Taken together, the results of the present study suggest that FTase inhibition by FTI-277 may be an effective strategy for targeting H-Ras-mediated proliferation, migration and invasion of breast cells.

  1. Farnesyl transferase inhibitor FTI-277 inhibits breast cell invasion and migration by blocking H-Ras activation

    PubMed Central

    Lee, Kyung Hun; Koh, Minsoo; Moon, Aree

    2016-01-01

    Hyperactive Ras promotes proliferation and malignant phenotypic conversion of cells in cancer. Ras protein must be associated with cellular membranes for its oncogenic activities through post-translational modifications, including farnesylation. Farnesyltransferase (FTase) is essential for H-Ras membrane targeting, and H-Ras, but not N-Ras, has been demonstrated to cause an invasive phenotype in MCF10A breast epithelial cells. In the present study, it was observed that an FTase inhibitor (FTI), FTI-277, blocked epidermal growth factor (EGF)-induced H-Ras activation, but not N-Ras activation in MDA-MB-231 cells, which express wild-type H-Ras and N-Ras. FTI-277 exerted a more potent inhibitory effect on the proliferation of H-Ras-MCF10A cells and Hs578T breast cancer cells expressing an active mutant of H-Ras than that of MDA-MB-231 cells. The invasive/migratory phenotypes of the H-Ras-MCF10A and Hs578T cells were effectively inhibited by FTI-277 treatment. By contrast, FTI-277 did not affect the invasive/migratory phenotypes of MDA-MB-231 cells. However, the EGF-induced invasion of MDA-MB-231 cells was decreased by FTI-277, implicating that FTI-277 inhibits breast cell invasion and migration by blocking H-Ras activation. Taken together, the results of the present study suggest that FTase inhibition by FTI-277 may be an effective strategy for targeting H-Ras-mediated proliferation, migration and invasion of breast cells. PMID:27602167

  2. A rapid and sensitive assay for determining human brain levels of farnesyl-(FPP) and geranylgeranylpyrophosphate (GGPP) and transferase activities using UHPLC-MS/MS.

    PubMed

    Hooff, Gero P; Patel, Nina; Wood, W Gibson; Müller, Walter E; Eckert, Gunter P; Volmer, Dietrich A

    2010-10-01

    The isoprenoids farnesyl-(FPP) and geranylgeranylpyrophosphate (FPP and GGPP) are two major lipid intermediates in the mevalonate pathway. They participate in post-translational modification of members of the superfamily of small guanosine triphosphatases (GTPases; Ras, Rab, Rac, etc.) via prenylation reactions. Due to the important role of these proteins in a number of cell processes, in particular cell growth, division, and differentiation, investigation of the involvement of isoprenoids in these processes is of great interest. In a previously published report, we described a fully validated assay for the quantitation of the two isoprenoids using a high-performance liquid chromatography (HPLC)-fluorescence detection (FLD) method. The current work expands on the previous method and enhances it greatly by using a much faster state-of-the-art ultrahigh-performance liquid chromatography (UHPLC) technique coupled to tandem mass spectrometry (MS/MS). The method exhibited a linear concentration range of 5-250 ng/mL for FPP and GGPP in human brain tissue; it was shown to be unaffected by ion suppression and provided results almost six times faster than the HPLC-FLD assay. Comparison of UHPLC-MS/MS and HPLC-FLD yielded excellent comparability of the two assays for both isoprenoids. Based on the UHPLC-MS/MS assay, a novel in vitro test system was implemented to study enzyme specificity for distinct amino acid CAAX motifs, which is potentially useful for investigating target interactions of new therapeutics for diseases involving pathological regulation of isoprenoids and/or small GTPases.

  3. Drug screening on Hutchinson Gilford progeria pluripotent stem cells reveals aminopyrimidines as new modulators of farnesylation.

    PubMed

    Blondel, S; Egesipe, A-L; Picardi, P; Jaskowiak, A-L; Notarnicola, M; Ragot, J; Tournois, J; Le Corf, A; Brinon, B; Poydenot, P; Georges, P; Navarro, C; Pitrez, P R; Ferreira, L; Bollot, G; Bauvais, C; Laustriat, D; Mejat, A; De Sandre-Giovannoli, A; Levy, N; Bifulco, M; Peschanski, M; Nissan, X

    2016-02-18

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by a dramatic appearance of premature aging. HGPS is due to a single-base substitution in exon 11 of the LMNA gene (c.1824C>T) leading to the production of a toxic form of the prelamin A protein called progerin. Because farnesylation process had been shown to control progerin toxicity, in this study we have developed a screening method permitting to identify new pharmacological inhibitors of farnesylation. For this, we have used the unique potential of pluripotent stem cells to have access to an unlimited and relevant biological resource and test 21,608 small molecules. This study identified several compounds, called monoaminopyrimidines, which target two key enzymes of the farnesylation process, farnesyl pyrophosphate synthase and farnesyl transferase, and rescue in vitro phenotypes associated with HGPS. Our results opens up new therapeutic possibilities for the treatment of HGPS by identifying a new family of protein farnesylation inhibitors, and which may also be applicable to cancers and diseases associated with mutations that involve farnesylated proteins.

  4. A phase I safety, pharmacological, and biological study of the farnesyl protein transferase inhibitor, lonafarnib (SCH 663366), in combination with cisplatin and gemcitabine in patients with advanced solid tumors

    PubMed Central

    Chow, Laura Q. M.; Eckhardt, S. Gail; O’Bryant, Cindy L.; Schultz, Mary Kay; Morrow, Mark; Grolnic, Stacy; Basche, Michele

    2010-01-01

    Purpose This phase I study was conducted to evaluate the safety, tolerability, pharmacological properties and biological activity of the combination of the lonafarnib, a farnesylproteintransferase (FTPase) inhibitor, with gemcitabine and cisplatin in patients with advanced solid malignancies. Experimental design This was a single institution study to determine the maximal tolerated dose (MTD) of escalating lonafarnib (75–125 mg po BID) with gemcitabine (750–1,000 mg/m2 on days 1, 8, 15) and fixed cisplatin (75 mg/m2 day 1) every 28 days. Due to dose-limiting toxicities (DLTs) of neutropenia and thrombocytopenia in initial patients, these patients were considered “heavily pretreated” and the protocol was amended to limit prior therapy and re-escalate lonafarnib in “less heavily pre-treated patients” on 28-day and 21-day schedules. Cycle 1 and 2 pharmacokinetics (PK), and farnesylation of the HDJ2 chaperone protein and FPTase activity were analyzed. Results Twenty-two patients received 53 courses of therapy. Nausea, vomiting, and fatigue were frequent in all patients. Severe toxicities were observed in 91% of patients: neutropenia (41%), nausea (36%), thrombocytopenia (32%), anemia (23%) and vomiting (23%). Nine patients withdrew from the study due to toxicity. DLTs of neutropenia, febrile neutropenia, thrombocytopenia, and fatigue limited dose-escalation on the 28-day schedule. The MTD was established as lonafarnib 75 mg BID, gemcitabine 750 mg/m2 days 1, 8, 15, and cisplatin 75 mg/m2 in heavily pre-treated patients. The MTD in the less heavily pre-treated patients could not be established on the 28-day schedule as DLTs were observed at the lowest dose level, and dose escalation was not completed on the 21-day schedule due to early study termination by the Sponsor. No PK interactions were observed. FTPase inhibition was not observed at the MTD, however HDJ-2 gel shift was observed in one patient at the 100 mg BID lonafarnib dose. Anti-cancer activity was

  5. Mutants of Saccharomyces cerevisiae defective in the farnesylation of Ras proteins.

    PubMed Central

    Goodman, L E; Judd, S R; Farnsworth, C C; Powers, S; Gelb, M H; Glomset, J A; Tamanoi, F

    1990-01-01

    Ras proteins are post-translationally modified by farnesylation. In the present investigation, we identified an activity in crude soluble extracts of yeast cells that catalyzes the transfer of a farnesyl moiety from farnesyl pyrophosphate to yeast RAS2 protein. RAS2 proteins having a C-terminal Cys-Ali-Ali-Xaa sequence (where Ali is an aliphatic amino acid and Xaa is the unspecified C-terminal amino acid) served as substrates for this reaction, whereas RAS2 proteins with an altered or deleted Cys-Ali-Ali-Xaa sequence did not. A yeast mutant, dpr1/ram1, originally isolated as a Ras-processing mutant was shown to be defective in farnesyltransferase activity. In addition, another mutant, ram2, also was defective in the transferase activity. These results demonstrate that at least two genes, DPR1/RAM1 and RAM2, are required for the farnesyltransferase activity in yeast. Images PMID:2124698

  6. Farnesylation Directs AtIPT3 Subcellular Localization and Modulates Cytokinin Biosynthesis in Arabidopsis1[OA

    PubMed Central

    Galichet, Arnaud; Hoyerová, Klára; Kamínek, Miroslav; Gruissem, Wilhelm

    2008-01-01

    Cytokinins regulate cell division and differentiation as well as a number of other processes implicated in plant development. The first step of cytokinin biosynthesis in Arabidopsis (Arabidopsis thaliana) is catalyzed by adenosine phosphate-isopentenyltransferases (AtIPT). The enzymes are localized in plastids or the cytoplasm where they utilize the intermediate dimethylallyl-diphosphate from the methylerythritolphosphate or mevalonic acid pathways. However, the regulatory mechanisms linking AtIPT activity and cytokinin biosynthesis with cytokinin homeostasis and isoprenoid synthesis are not well understood. Here, we demonstrate that expression of AtIPT3, one member of the adenosine AtIPT protein family in Arabidopsis, increased the production of specific isopentenyl-type cytokinins. Moreover, AtIPT3 is a substrate of the protein farnesyl transferase, and AtIPT3 farnesylation directed the localization of the protein in the nucleus/cytoplasm, whereas the nonfarnesylated protein was located in the plastids. AtIPT3 gain-of-function mutant analysis indicated that the different subcellular localization of the farnesylated protein and the nonfarnesylated protein was closely correlated with either isopentenyl-type or zeatin-type cytokinin biosynthesis. In addition, mutation of the farnesyl acceptor cysteine-333 of AtIPT3 abolishes cytokinin production, suggesting that cysteine-333 has a dual and essential role for AtIPT3 farnesylation and catalytic activity. PMID:18184738

  7. A novel role of farnesylation in targeting a mitotic checkpoint protein, human Spindly, to kinetochores

    PubMed Central

    Moudgil, Devinderjit K.; Westcott, Nathan; Famulski, Jakub K.; Patel, Kinjal; Macdonald, Dawn; Hang, Howard

    2015-01-01

    Kinetochore (KT) localization of mitotic checkpoint proteins is essential for their function during mitosis. hSpindly KT localization is dependent on the RZZ complex and hSpindly recruits the dynein–dynactin complex to KTs during mitosis, but the mechanism of hSpindly KT recruitment is unknown. Through domain-mapping studies we characterized the KT localization domain of hSpindly and discovered it undergoes farnesylation at the C-terminal cysteine residue. The N-terminal 293 residues of hSpindly are dispensable for its KT localization. Inhibition of farnesylation using a farnesyl transferase inhibitor (FTI) abrogated hSpindly KT localization without affecting RZZ complex, CENP-E, and CENP-F KT localization. We showed that hSpindly is farnesylated in vivo and farnesylation is essential for its interaction with the RZZ complex and hence KT localization. FTI treatment and hSpindly knockdown displayed the same mitotic phenotypes, indicating that hSpindly is a key FTI target in mitosis. Our data show a novel role of lipidation in targeting a checkpoint protein to KTs through protein–protein interaction. PMID:25825516

  8. Glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms, smoking, and their interaction in oral cancer: a HuGE review and meta-analysis.

    PubMed

    Zhang, Zhi-Jiang; Hao, Ke; Shi, Rong; Zhao, Genming; Jiang, Guo-Xin; Song, Yiqing; Xu, Xiaohui; Ma, Jin

    2011-04-15

    The association between glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) null polymorphisms and oral cancer is not consistent across studies, and data on their interaction with smoking in oral cancer are lacking. The authors systematically searched PubMed and SciVerse Scopus for case-control studies examining the association between null genotypes of the GSTM1 and GSTT1 genes and oral cancer. Twenty-eight case-control studies published in English were identified. Summary odds ratios were derived via random-effects models. The summary odds ratio for the GSTM1 null genotype was 1.43 in Asians (95% confidence interval (CI): 1.14, 1.78; P < 0.01, I (2) = 73%) and 0.98 in Caucasians (95% CI: 0.76, 1.28; P = 0.91, I (2) = 0%). Case-only analysis of 6 studies (552 cases) showed an inverse multiplicative interaction between GSTM1 null polymorphisms and smoking (ever/high levels of smoking vs. never/low levels) (odds ratio (OR) = 0.51, 95% CI: 0.32, 0.82; P = 0.01, I (2) = 34%). The GSTT1 null genotype was not significantly associated with oral cancer in Asians (OR = 1.07, 95% CI: 0.82, 1.38; P = 0.63, I (2) = 65%) or Caucasians (OR = 1.04, 95% CI: 0.41, 2.65; P = 0.93, I (2) = 55%). In conclusion, the GSTM1 null genotype may be associated with a higher risk of oral cancer in Asians but not in Caucasians, and this effect may be modified by smoking status. The GSTT1 null genotype may not be associated with oral cancer.

  9. Lamin A, farnesylation and aging

    SciTech Connect

    Reddy, Sita; Comai, Lucio

    2012-01-01

    Lamin A is a component of the nuclear envelope that is synthesized as a precursor prelamin A molecule and then processed into mature lamin A through sequential steps of posttranslational modifications and proteolytic cleavages. Remarkably, over 400 distinct point mutations have been so far identified throughout the LMNA gene, which result in the development of at least ten distinct human disorders, collectively known as laminopathies, among which is the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). The majority of HGPS cases are associated with a single point mutation in the LMNA gene that causes the production of a permanently farnesylated mutant lamin A protein termed progerin. The mechanism by which progerin leads to premature aging and the classical HGPS disease phenotype as well as the relationship between this disorder and the onset of analogous symptoms during the lifespan of a normal individual are not well understood. Yet, recent studies have provided critical insights on the cellular processes that are affected by accumulation of progerin and have suggested that cellular alterations in the lamin A processing pathway leading to the accumulation of farnesylated prelamin A intermediates may play a role in the aging process in the general population. In this review we provide a short background on lamin A and its maturation pathway and discuss the current knowledge of how progerin or alterations in the prelamin A processing pathway are thought to influence cell function and contribute to human aging.

  10. Lamin A, farnesylation and aging.

    PubMed

    Reddy, Sita; Comai, Lucio

    2012-01-01

    Lamin A is a component of the nuclear envelope that is synthesized as a precursor prelamin A molecule and then processed into mature lamin A through sequential steps of posttranslational modifications and proteolytic cleavages. Remarkably, over 400 distinct point mutations have been so far identified throughout the LMNA gene, which result in the development of at least ten distinct human disorders, collectively known as laminopathies, among which is the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). The majority of HGPS cases are associated with a single point mutation in the LMNA gene that causes the production of a permanently farnesylated mutant lamin A protein termed progerin. The mechanism by which progerin leads to premature aging and the classical HGPS disease phenotype as well as the relationship between this disorder and the onset of analogous symptoms during the lifespan of a normal individual are not well understood. Yet, recent studies have provided critical insights on the cellular processes that are affected by accumulation of progerin and have suggested that cellular alterations in the lamin A processing pathway leading to the accumulation of farnesylated prelamin A intermediates may play a role in the aging process in the general population. In this review we provide a short background on lamin A and its maturation pathway and discuss the current knowledge of how progerin or alterations in the prelamin A processing pathway are thought to influence cell function and contribute to human aging.

  11. Farnesyl pyrophosphate is a novel transcriptional activator for a subset of nuclear hormone receptors.

    PubMed

    Das, Sharmistha; Schapira, Matthieu; Tomic-Canic, Marjana; Goyanka, Ritu; Cardozo, Timothy; Samuels, Herbert H

    2007-11-01

    In silico docking of a chemical library with the ligand-binding domain of thyroid hormone nuclear receptor-beta (TRbeta) suggested that farnesyl pyrophosphate (FPP), a key intermediate in cholesterol synthesis and protein farnesylation, might function as an agonist. Surprisingly, addition of FPP to cells activated TR as well as the classical steroid hormone receptors but not peroxisome proliferative-activating receptors, farnesoid X receptor, liver X receptor, or several orphan nuclear receptors the ligands of which are unknown. FPP enhanced receptor-coactivator binding in vitro and in vivo, and elevation of FPP levels in cells by squalene synthetase or farnesyl transferase inhibitors leads to activation. The FPP effect was blocked by selective receptor antagonists, and in silico docking with 143 nuclear receptor ligand-binding domain structures revealed that FPP only docked with the agonist conformation of those receptors activated by FPP. Our results suggest that certain nuclear receptors maintain a common structural feature that may reflect an action of FPP on an ancient nuclear receptor or that FPP could function as a ligand for one of the many orphan nuclear receptors the ligands of which have not yet been identified. This finding also has potential interesting implications that may, in part, explain the pleotropic effects of statins as well as certain actions of farnesylation inhibitors in cells.

  12. The synergy of tobacco and alcohol and glutathione S-transferase θ 1 gene deletion and oral squamous cell carcinoma

    PubMed Central

    D’ Mello, Sarah; Bavle, Radhika Manoj; Paremala, K; Makarla, Soumya; Sudhakara, M; Bhatt, Madhura

    2016-01-01

    Background: Oral squamous cell carcinoma (OSCC) is the leading cancer among males in India. It is related to tobacco habits and alcohol consumption as well as the individual susceptibility for xenobiotic metabolizing enzyme polymorphisms. Glutathione S-transferase θ 1 (GSTT1) is a Phase II metabolic enzyme which is directly involved in catalyzing chemicals to mutagenic intermediates. This gene is characterized by genetic polymorphism resulting in complete gene deletion and subsequent absence of the enzyme, which ultimately dictates the risk of cancer development. Scraping buccal mucosa to obtain DNA from the cells is a simple, readily acceptable and rapid method to detect and assess the gene. Aim: To assess GSTT1 gene deletion in individuals giving a history of tobacco smoking and/or chewing and alcohol consumption and absence of clinically detectable lesions; and in OSCC cases to gauge if GSTT1 gene deletion confers protection to an individual and whether it can be used as a “single” marker to arrive at this conclusion. To validate the use of buccal scrape for determining the genotype of an individual by assessing the polymorphism at GSTT1 gene locus (22q11.2). Materials and Methods: Fifty-two cases were evaluated using buccal mucosal scrapes of tobacco habituates for 8 or more years, without clinically evident lesion (Group I) and from mucosa of tobacco habituates with clinically evident and histopathologically confirmed OSCC (Group II). DNA extraction and genotype at GSTT1 gene locus was determined by polymerase chain reaction assay. Statistical Analysis: The results were statistically analyzed using Chi-square test. Results: 90.66% of subjects had GSTT1 null genotype in Group I subjects. In Group II, subjects with both clinically and histopathologically diagnosed oral cancer, about 76.96% had GSTT1 null genotype. Conclusion: GSTT1 null genotype confers protection to individuals with tobacco habits and alcohol consumption, predominantly to those who used

  13. Prevalence of glutathione S-transferase M1 null polymorphism in tobacco users, oral leukoplakia and oral squamous cell carcinoma patients in South Indian population: A polymerase chain reaction study.

    PubMed

    Tanwar, Renu; Iyengar, Asha R; Nagesh, K S; Patil, Seema; Subhash, B V

    2015-03-01

    Tobacco abuse is a well-known risk factor for potentially malignant disorders as well as oral squamous cell carcinoma (SCC). Factors that influence tobacco-exposed individuals developing a malignancy may include a combination of total tobacco exposure and genetic susceptibility. This study was undertaken to determine the prevalence of the glutathione S-transferase M1 (GSTM1) null polymorphism in oral leukoplakia and oral SCC patients in South Indian population. This case-control study was conducted in hospital setting on South Indian population. Totally, 280 subjects with a history of tobacco use, oral leukoplakia, oral SCC were included in this study. Three milliliter of blood was collected and transported under cold cycle and taken for evaluation of GSTM1 null polymorphism using Multiplex Polymerase Chain Reaction. On comparing the prevalence of GSTM1 null polymorphism among the group with subjects with habits and no oral lesions, oral leukoplakia and oral SCC, it was observed that there was a statistically significant association between GSTM1 null polymorphism and the different groups (P < 0.01). The lack of GSTM1 activity would make the oral tissues more susceptible to action of tobacco carcinogens and to the development of a high-grade level of dysplasia in oral leukoplakia and thereby increases the susceptibility of lesion to undergo malignant changes.

  14. Recent advances in oral anticancer agents for colon cancer.

    PubMed

    Shukla, Raj Kumar

    2013-12-01

    To provide therapeutic alternatives to intravenous colon chemotherapy major recent research is focusing on the development of oral chemotherapeutic agents with the intention to improve the quality of life of patients. Initially 5-fluorouracil was most commonly used for the treatment of colorectal cancer but currently oxaliplatin and irinotecan are also available. The majority of these new drugs are pyrimidines and their analogs. The rationale for using oral anticancer agents is discussed and new drugs, such as farnesyl protein transferase inhibitor S-1, rubitecan, ZD9331, MMI-166, eflornithine, sulindac, and oral camptothecin analogs, among others, are presented with the results of their preclinical and clinical developments. This article focuses on the advancement of clinical development and also discusses the relative merits and demerits of these agents. The accelerated approval of these agents by regulatory authorities is supported by survival benefit, response rate and time to progression.

  15. The gamma subunit of transducin is farnesylated.

    PubMed Central

    Lai, R K; Perez-Sala, D; Cañada, F J; Rando, R R

    1990-01-01

    Protein prenylation with farnesyl or geranylgeranyl moieties is an important posttranslational modification that affects the activity of such diverse proteins as the nuclear lamins, the yeast mating factor mata, and the ras oncogene products. In this article, we show that whole retinal cultures incorporate radioactive mevalonic acid into proteins of 23-26 kDa and one of 8 kDa. The former proteins are probably the "small" guanine nucleotide-binding regulatory proteins (G proteins) and the 8-kDa protein is the gamma subunit of the well-studied retinal heterotrimeric G protein (transducin). After deprenylating purified transducin and its subunits with Raney nickel or methyl iodide/base, the adducted prenyl group can be identified as an all-trans-farnesyl moiety covalently linked to a cysteine residue. Thus far, prenylation reactions have been found to occur at cysteine in a carboxyl-terminal consensus CAAX sequence, where C is the cysteine, A is an aliphatic amino acid, and X is undefined. Both the alpha and gamma subunits of transducin have this consensus sequence, but only the gamma subunit is prenylated. Therefore, the CAAX motif is not necessary and sufficient to direct prenylation. Finally, since transducin is the best understood G protein, both structurally and mechanistically, the discovery that it is farnesylated should allow for a quantitative understanding of this post-translational modification. Images PMID:2217200

  16. Glutathione S-transferase GSTT1 genotypes and susceptibility to cancer: studies of interactions with GSTM1 in lung, oral, gastric and colorectal cancers.

    PubMed

    Deakin, M; Elder, J; Hendrickse, C; Peckham, D; Baldwin, D; Pantin, C; Wild, N; Leopard, P; Bell, D A; Jones, P; Duncan, H; Brannigan, K; Alldersea, J; Fryer, A A; Strange, R C

    1996-04-01

    Allelism in glutathione S-transferase GSTM1 and GSTT1 has been suggested as a risk factor in various cancers. Accordingly, we describe a group of case-control studies carried out to identify associations between GSTT1 genotypes and susceptibility to lung, oral, gastric and colorectal cancers. The frequencies of the putatively high risk GSTT1 null genotype were not increased in the lung, oral or gastric cancer cases compared with controls but the frequency of this genotype was significantly increased (P = 0.0011, odds ratio = 1.88) in the colorectal cancer cases. No significant interactions between the GSTT1 and GSTM1 null genotypes types were identified in the cancer groups studied. Indeed, no significant associations between GSTM1 genotypes and susceptibility were identified though further evidence was obtained that the protective effect of GSTM1*A and GSTM1*B is not equal. The data complement studies showing that GSTT1 null is associated with an increased susceptibility to total ulcerative colitis and suggests that this enzyme is important in the detoxification of unidentified xenobiotics in the large intestine.

  17. Macagigantin, a farnesylated flavonol from Macaranga gigantea.

    PubMed

    Tanjung, Mulyadi; Hakim, Euis H; Mujahidin, Didin; Hanafi, Muhammad; Syah, Yana M

    2009-11-01

    A new farnesylated flavonol derivative, macagigantin (1), together with two known flavonoids, glyasperin A (2) and apigenin (3), had been isolated from the acetone extract of the leaves of Macaranga gigantea. The structure of the new compound was elucidated as 6-farnesylkaempferol based on its spectroscopic data, including UV, IR, 1D and 2D NMR, and HR-EI-MS spectra. Compounds 1-3 were evaluated for their cytotoxic properties against P-388 cells, their IC(50) values being 11.3, 6.0, and 5.1 microM, respectively.

  18. Farnesyl pyrophosphate regulates adipocyte functions as an endogenous PPARγ agonist.

    PubMed

    Goto, Tsuyoshi; Nagai, Hiroyuki; Egawa, Kahori; Kim, Young-Il; Kato, Sota; Taimatsu, Aki; Sakamoto, Tomoya; Ebisu, Shogo; Hohsaka, Takahiro; Miyagawa, Hiroh; Murakami, Shigeru; Takahashi, Nobuyuki; Kawada, Teruo

    2011-08-15

    The cholesterol biosynthetic pathway produces not only sterols but also non-sterol mevalonate metabolites involved in isoprenoid synthesis. Mevalonate metabolites affect transcriptional and post-transcriptional events that in turn affect various biological processes including energy metabolism. In the present study, we examine whether mevalonate metabolites activate PPARγ (peroxisome-proliferator-activated receptor γ), a ligand-dependent transcription factor playing a central role in adipocyte differentiation. In the luciferase reporter assay using both GAL4 chimaera and full-length PPARγ systems, a mevalonate metabolite, FPP (farnesyl pyrophosphate), which is the precursor of almost all isoprenoids and is positioned at branch points leading to the synthesis of other longer-chain isoprenoids, activated PPARγ in a dose-dependent manner. FPP induced the in vitro binding of a co-activator, SRC-1 (steroid receptor co-activator-1), to GST (glutathione transferase)-PPARγ. Direct binding of FPP to PPARγ was also indicated by docking simulation studies. Moreover, the addition of FPP up-regulated the mRNA expression levels of PPARγ target genes during adipocyte differentiation induction. In the presence of lovastatin, an HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase inhibitor, both intracellular FPP levels and PPARγ-target gene expressions were decreased. In contrast, the increase in intracellular FPP level after the addition of zaragozic acid, a squalene synthase inhibitor, induced PPARγ-target gene expression. The addition of FPP and zaragozic acid promotes lipid accumulation during adipocyte differentiation. These findings indicated that FPP might function as an endogenous PPARγ agonist and regulate gene expression in adipocytes. © The Authors Journal compilation © 2011 Biochemical Society

  19. Farnesyl pyrophosphate regulates adipocyte functions as an endogenous PPARγ agonist

    PubMed Central

    Goto, Tsuyoshi; Nagai, Hiroyuki; Egawa, Kahori; Kim, Young-Il; Kato, Sota; Taimatsu, Aki; Sakamoto, Tomoya; Ebisu, Shogo; Hohsaka, Takahiro; Miyagawa, Hiroh; Murakami, Shigeru; Takahashi, Nobuyuki; Kawada, Teruo

    2011-01-01

    The cholesterol biosynthetic pathway produces not only sterols but also non-sterol mevalonate metabolites involved in isoprenoid synthesis. Mevalonate metabolites affect transcriptional and post-transcriptional events that in turn affect various biological processes including energy metabolism. In the present study, we examine whether mevalonate metabolites activate PPARγ (peroxisome-proliferator-activated receptor γ), a ligand-dependent transcription factor playing a central role in adipocyte differentiation. In the luciferase reporter assay using both GAL4 chimaera and full-length PPARγ systems, a mevalonate metabolite, FPP (farnesyl pyrophosphate), which is the precursor of almost all isoprenoids and is positioned at branch points leading to the synthesis of other longer-chain isoprenoids, activated PPARγ in a dose-dependent manner. FPP induced the in vitro binding of a co-activator, SRC-1 (steroid receptor co-activator-1), to GST (glutathione transferase)–PPARγ. Direct binding of FPP to PPARγ was also indicated by docking simulation studies. Moreover, the addition of FPP up-regulated the mRNA expression levels of PPARγ target genes during adipocyte differentiation induction. In the presence of lovastatin, an HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) reductase inhibitor, both intracellular FPP levels and PPARγ-target gene expressions were decreased. In contrast, the increase in intracellular FPP level after the addition of zaragozic acid, a squalene synthase inhibitor, induced PPARγ-target gene expression. The addition of FPP and zaragozic acid promotes lipid accumulation during adipocyte differentiation. These findings indicated that FPP might function as an endogenous PPARγ agonist and regulate gene expression in adipocytes. PMID:21605082

  20. Influence of class M1 glutathione S-transferase (GST Mu) polymorphism on GST M1 gene expression level and tumor size in oral squamous cell carcinoma.

    PubMed

    Koch, F P; Kämmerer, P W; Kämmerer, P; Al-Nawas, B; Brieger, J

    2010-02-01

    Glutathione S-transferases (GST) are antioxidant enzymes and oxidative stress markers in oral carcinogenesis. They present a system of polymorphic proteins. Some variants are associated with increased sensitivity to toxic compounds, as it is known for the GSTM1-null variant allele. However, the influence of the GSTM1 allele variant genotype on GSTM1-mRNA quantity in oral squamous cell carcinoma (OSCC) and normal mucosa as well as the impact on prognosis remains unclear. The genotype for GSTM1 (mutation vs. wild type) was determined by polymerase chain reaction (PCR) using genomic DNA extracted from peripheral blood from 28 OSCC patients. From the same patients, 28 pairs of OSCC cells and normal oral mucosal cells were obtained by brush biopsy. mRNA was extracted from these paired samples and the expression levels of GSTM1 were examined by real-time reverse transcriptase qPCR (RT-qPCR). The mRNA expression of the OSCC samples was normalized against an external standard, as well as to the corresponding normal mucosa. The coincidence of GSTM1 genotype and GSTM1-mRNA-expression level was examined. In 15 patients (54%), the null genotype GSTM1 was present. In the GSTM1-null allele group, the GSTM1 gene expression level was determined at 1.63 (mean: 3.08; SD 3.4) folds vs. 3.6 (mean: 10.5; SD 14.2) folds in the group with the positive genotype (p=0.06), if calibrated vs. individual normal mucosa. More T3 and T4 OSCCs (+38%), higher UICC stadia (+38%) and more lymphatic metastasis (+28%) were seen in the group with the negative allele. Furthermore, positive GSTM1 genotype and enhanced GSTM1 gene expression was accompanied with increased tumor size, lymphatic metastasis status and UICC stadium. A coincidence of null type GSTM1 and lowered GSTM1 gene expression was observed. The larger tumors and more frequent lymph node metastases in this group could be explained by the insufficient cell protection by GST.

  1. Farnesylation or geranylgeranylation? Efficient assays for testing protein prenylation in vitro and in vivo

    PubMed Central

    Benetka, Wolfgang; Koranda, Manfred; Maurer-Stroh, Sebastian; Pittner, Fritz; Eisenhaber, Frank

    2006-01-01

    Background Available in vitro and in vivo methods for verifying protein substrates for posttranslational modifications via farnesylation or geranylgeranylation (for example, autoradiography with 3H-labeled anchor precursors) are time consuming (weeks/months), laborious and suffer from low sensitivity. Results We describe a new technique for detecting prenyl anchors in N-terminally glutathione S-transferase (GST)-labeled constructs of target proteins expressed in vitro in rabbit reticulocyte lysate and incubated with 3H-labeled anchor precursors. Alternatively, hemagglutinin (HA)-labeled constructs expressed in vivo (in cell culture) can be used. For registration of the radioactive marker, we propose to use a thin layer chromatography (TLC) analyzer. As a control, the protein yield is tested by Western blotting with anti-GST- (or anti-HA-) antibodies on the same membrane that has been previously used for TLC-scanning. These protocols have been tested with Rap2A, v-Ki-Ras2 and RhoA (variant RhoA63L) including the necessary controls. We show directly that RasD2 is a farnesylation target. Conclusion Savings in time for experimentation and the higher sensitivity for detecting 3H-labeled lipid anchors recommend the TLC-scanning method with purified GST- (or HA-) tagged target proteins as the method of choice for analyzing their prenylation capabilities in vitro and in vivo and, possibly, also for studying the myristoyl and palmitoyl posttranslational modifications. PMID:16507103

  2. Glutathione Transferases

    PubMed Central

    Dixon, David P.; Edwards, Robert

    2010-01-01

    The 55 Arabidopsis glutathione transferases (GSTs) are, with one microsomal exception, a monophyletic group of soluble enzymes that can be divided into phi, tau, theta, zeta, lambda, dehydroascorbate reductase (DHAR) and TCHQD classes. The populous phi and tau classes are often highly stress inducible and regularly crop up in proteomic and transcriptomic studies. Despite much study on their xenobiotic-detoxifying activities their natural roles are unclear, although roles in defence-related secondary metabolism are likely. The smaller DHAR and lambda classes are likely glutathione-dependent reductases, the zeta class functions in tyrosine catabolism and the theta class has a putative role in detoxifying oxidised lipids. This review describes the evidence for the functional roles of GSTs and the potential for these enzymes to perform diverse functions that in many cases are not “glutathione transferase” activities. As well as biochemical data, expression data from proteomic and transcriptomic studies are included, along with subcellular localisation experiments and the results of functional genomic studies. PMID:22303257

  3. Characterizing guayule rubber transferase activity

    SciTech Connect

    Cornish, K.; Backhaus, R.A. )

    1989-04-01

    Rubber transferase (RuT) activity, measured as incorporation of {sup 14}C(isopentenyl pyrophosphate) (IPP) into rubber, was assayed in suspensions of rubber particles purified from bark tissue of Parthenium argentatum, Gray. Rubber particle suspensions (RSP) have high RuT activity which is not diminished by repeated washing of the particles, demonstrating the firm association of the enzyme system with the particles. RuT activity varied with line: 11591 yielded more rubber particles with a greater activity per particle, than did other lines tested. Variation in activity also varied with bark age and season. Activity rapidly declined at temperatures above 16{degree}C in line 593, but was more stable in RSP isolated form line 11591. IPP-incorporation depends upon the concentration of two substrates, IPP and the starter molecule farnesyl pyrophosphate (FPP). In lines 593 and 11591, 20 uM FPP saturated the enzyme present in 6 {times} 10{sup 10} particles {times} cm{sup {minus}3}, whereas about 1 mM IPP was required for saturation. Under saturating FPP, the apparent K{sub m} of RuT was about 250 uM.

  4. Quantitative determination of farnesyl and geranylgeranyl diphosphate levels in mammalian tissue.

    PubMed

    Tong, Huaxiang; Wiemer, Andrew J; Neighbors, Jeffrey D; Hohl, Raymond J

    2008-07-15

    Farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP) are branch point intermediates of isoprenoid biosynthesis. Inhibitors of isoprenoid biosynthesis, such as the statins and bisphosphonates, are widely used therapeutic agents. However, little is known about the degree to which they alter levels of upstream and downstream isoprenoids, including FPP and GGPP. Therefore, we developed a method to isolate and quantify FPP and GGPP from mammalian tissues. Tissues from mice were collected, snap frozen in liquid nitrogen, and stored at -80 degrees C. FPP and GGPP were isolated by a combined homogenization and extraction procedure and were purified with a C18 solid phase extraction column. Farnesyl protein transferase (FTase) or geranylgeranyl protein transferase I (GGTase I) were used to conjugate FPP and GGPP with fluorescent dansylated peptides. FPP and GGPP were quantified by high-performance liquid chromatography (HPLC). The respective concentrations of FPP and GGPP are as follows: 0.355+/-0.030 and 0.827+/-0.082 units of nmol/g wet tissues in brain, 0.320+/-0.019 and 0.293+/-0.035 units of nmol/g wet tissues in kidney, 0.326+/-0.064 and 0.213+/-0.029 units of nmol/g wet tissues in liver, and 0.364+/-0.015 and 0.349+/-0.023 units of nmol/g wet tissues in heart (means+/-SEM). This method allows for determination of FPP and GGPP concentrations in any tissue type and is sensitive enough to detect changes following treatment with inhibitors of isoprenoid biosynthesis.

  5. Pex19p, a Farnesylated Protein Essential for Peroxisome Biogenesis

    PubMed Central

    Götte, Klaudia; Girzalsky, Wolfgang; Linkert, Michael; Baumgart, Evelyn; Kammerer, Stefan; Kunau, Wolf-Hubert; Erdmann, Ralf

    1998-01-01

    We report the identification and molecular characterization of Pex19p, an oleic acid-inducible, farnesylated protein of 39.7 kDa that is essential for peroxisome biogenesis in Saccharomyces cerevisiae. Cells lacking Pex19p are characterized by the absence of morphologically detectable peroxisomes and mislocalization of peroxisomal matrix proteins to the cytosol. The human HK33 gene product was identified as the putative human ortholog of Pex19p. Evidence is provided that farnesylation of Pex19p takes place at the cysteine of the C-terminal CKQQ amino acid sequence. Farnesylation of Pex19p was shown to be essential for the proper function of the protein in peroxisome biogenesis. Pex19p was shown to interact with Pex3p in vivo, and this interaction required farnesylation of Pex19p. PMID:9418908

  6. Alendronate is a specific, nanomolar inhibitor of farnesyl diphosphate synthase.

    PubMed

    Bergstrom, J D; Bostedor, R G; Masarachia, P J; Reszka, A A; Rodan, G

    2000-01-01

    Alendronate, a nitrogen-containing bisphosphonate, is a potent inhibitor of bone resorption used for the treatment and prevention of osteoporosis. Recent findings suggest that alendronate and other N-containing bisphosphonates inhibit the isoprenoid biosynthesis pathway and interfere with protein prenylation, as a result of reduced geranylgeranyl diphosphate levels. This study identified farnesyl disphosphate synthase as the mevalonate pathway enzyme inhibited by bisphosphonates. HPLC analysis of products from a liver cytosolic extract narrowed the potential targets for alendronate inhibition (IC(50) = 1700 nM) to isopentenyl diphosphate isomerase and farnesyl diphosphate synthase. Recombinant human farnesyl diphosphate synthase was inhibited by alendronate with an IC(50) of 460 nM (following 15 min preincubation). Alendronate did not inhibit isopentenyl diphosphate isomerase or GGPP synthase, partially purified from liver cytosol. Recombinant farnesyl diphosphate synthase was also inhibited by pamidronate (IC(50) = 500 nM) and risedronate (IC(50) = 3.9 nM), negligibly by etidronate (IC50 = 80 microM), and not at all by clodronate. In osteoclasts, alendronate inhibited the incorporation of [(3)H]mevalonolactone into proteins of 18-25 kDa and into nonsaponifiable lipids, including sterols. These findings (i) identify farnesyl diphosphate synthase as the selective target of alendronate in the mevalonate pathway, (ii) show that this enzyme is inhibited by other N-containing bisphosphonates, such as risendronate, but not by clodronate, supporting a different mechanism of action for different bisphosphonates, and (iii) document in purified osteoclasts alendronate inhibition of prenylation and sterol biosynthesis.

  7. The mevalonate pathway regulates primitive streak formation via protein farnesylation

    PubMed Central

    Okamoto-Uchida, Yoshimi; Yu, Ruoxing; Miyamura, Norio; Arima, Norie; Ishigami-Yuasa, Mari; Kagechika, Hiroyuki; Yoshida, Suguru; Hosoya, Takamitsu; Nawa, Makiko; Kasama, Takeshi; Asaoka, Yoichi; Alois, Reiner Wimmer; Elling, Ulrich; Penninger, Josef M.; Nishina, Sachiko; Azuma, Noriyuki; Nishina, Hiroshi

    2016-01-01

    The primitive streak in peri-implantation embryos forms the mesoderm and endoderm and controls cell differentiation. The metabolic cues regulating primitive streak formation remain largely unknown. Here we utilised a mouse embryonic stem (ES) cell differentiation system and a library of well-characterised drugs to identify these metabolic factors. We found that statins, which inhibit the mevalonate metabolic pathway, suppressed primitive streak formation in vitro and in vivo. Using metabolomics and pharmacologic approaches we identified the downstream signalling pathway of mevalonate and revealed that primitive streak formation requires protein farnesylation but not cholesterol synthesis. A tagging-via-substrate approach revealed that nuclear lamin B1 and small G proteins were farnesylated in embryoid bodies and important for primitive streak gene expression. In conclusion, protein farnesylation driven by the mevalonate pathway is a metabolic cue essential for primitive streak formation. PMID:27883036

  8. Farnesyl transferase inhibitors, autophagy, and proteasome inhibition: synergy for all the right reasons.

    PubMed

    Lonial, Sagar; Boise, Lawrence H

    2011-04-01

    The increasing appreciation of the importance of autophagy as consequence of cancer therapy or underlying disease biology is illustrated by the large number of papers that are evaluating autophagy as a cancer target. While autophagy is often linked to the generation of metabolic precursors, it is also important in diseases where protein production is a hallmark of the disease itself, such as pancreatic cancer and multiple myeloma. Multiple myeloma is characterized by ongoing autophagy as a consequence of constitutive immunoglobulin production, which creates the need for efficient transfer and disposal of misfolded or unfolded proteins. In order to survive this cellular stress, plasma cells depend on proteasomal degradation of the large volume of misfolded proteins as well as the autophagy pathway. It has previously been suggested that the excess proteins not targeted to the proteasome, or that accumulate when the proteasome is inhibited through the use of chemically active agents such as bortezomib, are linked to impaired cell survival, and that their packaging in the form of an aggresome somehow minimizes their 'proteotoxicity' allowing these toxic proteins to be sequestered away from normal cellular machinery.

  9. Nitrogen-containing bisphosphonates inhibit isopentenyl pyrophosphate isomerase/farnesyl pyrophosphate synthase activity with relative potencies corresponding to their antiresorptive potencies in vitro and in vivo.

    PubMed

    van Beek, E; Pieterman, E; Cohen, L; Löwik, C; Papapoulos, S

    1999-02-16

    Bisphosphonates, synthetic compounds which suppress bone resorption, are used in the treatment of skeletal disorders. Their mode of action and intracellular targets have not yet been identified. Recent evidence suggested that enzymes of the mevalonate pathway are the potential targets. In this study, we examined the effect of four potent nitrogen (N)-containing bisphosphonates, clodronate and NH2-olpadronate, an inactive analogue of olpadronate, on isopentenyl pyrophosphate isomerase/farnesyl pyrophosphate synthase, geranylgeranyl pyrophosphate synthase, and protein geranylgeranyl transferase I activity. We found that all N-containing bisphosphonates inhibited isopentenyl pyrophosphate isomerase/farnesyl pyrophosphate synthase activity dose dependently with relative potencies corresponding to their antiresorptive potencies in vitro and in vivo, whereas clodronate and NH2-olpadronate had no effect. Furthermore, none of the bisphosphonates tested affected geranylgeranyl pyrophosphate synthase or geranylgeranyl transferase I activity. Our study reveals for the first time the intracellular target of N-containing bisphosphonates and supports the view that all bisphosphonates do not share the same molecular mechanism of action. Copyright 1999 Academic Press.

  10. Protein farnesyltransferase: kinetics of farnesyl pyrophosphate binding and product release.

    PubMed

    Furfine, E S; Leban, J J; Landavazo, A; Moomaw, J F; Casey, P J

    1995-05-23

    Protein farnesyltransferase (FTase) catalyzes the prenylation of Ras and several other key proteins involved in cell regulation. The mechanism of the FTase reaction was elucidated by pre-steady-state and steady-state kinetic analysis. FTase catalyzed the farnesylation of biotinylated peptide substrate (BiopepSH) by farnesyl pyrophosphate (FPP) to an S-farnesylated peptide (BiopepS-C15). The steady-state kinetic mechanism was ordered. FTase bound FPP in a two-step process with an effective dissociation rate constant of 0.013 s-1 and an overall Kd of 2.8 nM. BiopepSH reacted with FTase.FPP irreversibly, with a second-order rate constant of 2.2 x 10(5) M-1 s-1, to form FTase.BiopepS-C15. Because most of the FPP in FTase.FPP was trapped as FTase.BiopepS-C15 at high concentrations of BiopepSH, FPP dissociated slowly from the ternary complex relative to catalysis, so that the commitment to catalysis was high. The maximal rate constant for formation of FTase.BiopepS-C15 (enzyme-bound product) is much larger than kcat (0.06 s-1), indicating that product release is the rate-determining step in the reaction mechanism.

  11. A tagging-via-substrate technology for genome-wide detection and identification of farnesylated proteins.

    PubMed

    Chan Kim, Sung; Kho, Yoonjung; Barma, Deb; Falck, John; Zhao, Yingming

    2006-01-01

    Protein farnesylation is one of the most common lipid modifications and has an important role in the regulation of various cellular functions. We have recently developed a novel proteomics strategy, designated the tagging-via-substrate (TAS) approach, for the detection and proteomic analysis of farnesylated proteins. This chapter describes the principle of TAS technology and details the method for detection and enrichment of farnesylated proteins.

  12. Propiconazole-enhanced hepatic cell proliferation is associated with dysregulation of the cholesterol biosynthesis pathway leading to activation of Erk1/2 through Ras farnesylation

    SciTech Connect

    Murphy, Lynea A.; Moore, Tanya; Nesnow, Stephen

    2012-04-15

    Propiconazole is a mouse hepatotumorigenic fungicide designed to inhibit CYP51, a key enzyme in the biosynthesis of ergosterol in fungi and is widely used in agriculture to prevent fungal growth. Metabolomic studies in mice revealed that propiconazole increased levels of hepatic cholesterol metabolites and bile acids, and transcriptomic studies revealed that genes within the cholesterol biosynthesis, cholesterol metabolism and bile acid biosyntheses pathways were up-regulated. Hepatic cell proliferation was also increased by propiconazole. AML12 immortalized hepatocytes were used to study propiconazole's effects on cell proliferation focusing on the dysregulation of cholesterol biosynthesis and resulting effects on Ras farnesylation and Erk1/2 activation as a primary pathway. Mevalonate, a key intermediate in the cholesterol biosynthesis pathway, increases cell proliferation in several cancer cell lines and tumors in vivo and serves as the precursor for isoprenoids (e.g. farnesyl pyrophosphate) which are crucial in the farnesylation of the Ras protein by farnesyl transferase. Farnesylation targets Ras to the cell membrane where it is involved in signal transduction, including the mitogen-activated protein kinase (MAPK) pathway. In our studies, mevalonic acid lactone (MVAL), a source of mevalonic acid, increased cell proliferation in AML12 cells which was reduced by farnesyl transferase inhibitors (L-744,832 or manumycin) or simvastatin, an HMG-CoA reductase inhibitor, indicating that this cell system responded to alterations in the cholesterol biosynthesis pathway. Cell proliferation in AML12 cells was increased by propiconazole which was reversed by co-incubation with L-744,832 or simvastatin. Increasing concentrations of exogenous cholesterol muted the proliferative effects of propiconazole and the inhibitory effects of L-733,832, results ascribed to reduced stimulation of the endogenous cholesterol biosynthesis pathway. Western blot analysis of subcellular

  13. Endoproteolytic processing of a farnesylated peptide in vitro.

    PubMed Central

    Ashby, M N; King, D S; Rine, J

    1992-01-01

    Numerous eukaryotic proteins containing a carboxyl-terminal CAAX motif (C, cysteine; A, aliphatic amino acid; X, any amino acid) require a three-step posttranslational processing for localization and function. The a mating factor of Saccharomyces cerevisiae is one such protein, requiring cysteine farnesylation, proteolysis of the terminal three amino acids, and carboxyl methylation for biological activity. We have used farnesylated a-factor peptides to examine the proteolytic step in the maturation of CAAX-containing proteins. Three distinct carboxyl-terminal protease activities were found in yeast cell extracts that could remove the terminal three residues of a-factor. Two of the proteolytic activities were in cytosolic fractions. One of these activities was a PEP4-dependent carboxypeptidase that was sensitive to phenylmethylsulfonyl fluoride. The other cytosolic activity was PEP4-independent, sensitive to 1,10-phenanthroline, and effectively inhibited by an unfarnesylated a-factor peptide. In contrast, a protease activity in membrane fractions was unaffected by phenylmethylsulfonyl fluoride, 1,10-phenanthroline, or unfarnesylated a-factor peptide. Incubation of membrane preparations from either yeast or rat liver with a radiolabeled farnesylated a-factor peptide released the terminal three amino acids intact as a tripeptide, indicating that this reaction occurred by an endoproteolytic mechanism and that the enzyme most likely possesses a broad substrate specificity. The yeast endoprotease was not significantly affected by a panel of protease inhibitors, suggesting that the enzyme is novel. Zinc ion was shown to inhibit the endoprotease (Ki less than 100 microM). The specific activities of the a-factor carboxyl-terminal membrane endoprotease and methyltransferase clearly indicated that the proteolytic reaction was not rate-limiting in these processing reactions in vitro. PMID:1584798

  14. Increased amounts of farnesylated p21Ras in tissues of hyperinsulinaemic animals.

    PubMed

    Goalstone, M L; Wall, K; Leitner, J W; Kurowski, T; Ruderman, N; Pan, S J; Ivy, J L; Moller, D E; Draznin, B

    1999-03-01

    We have recently demonstrated that insulin activates farnesyltransferase (FTase) and thereby increases the amounts of cellular farnesylated p21Ras in 3T3-L1 fibroblasts, adipocytes and vascular smooth muscle cells. We postulated that hyperinsulinaemia might considerably increase the the cellular pool of farnesylated p21Ras available for activation by other growth factors. To examine the role of in vivo hyperinsulinaemia in regulating farnesylated p21Ras, we measured the amounts of farnesylated p21Ras in tissues of hyperinsulinaemic animals. Liver, aorta, and skeletal muscle of ob/ob mice, and mice made obese and hyperinsulinaemic by injection of gold-thioglucose contained greater amounts of farnesylated p21Ras than tissues of their lean normoinsulinaemic counterparts. Similarly, farnesylated p21Ras was increased (67 vs. 35 % in control animals, p<0.01) in the livers of hyperinsulinaemic Zucker rats (fa/fa). Reduction of hyperinsulinaemia by exercise training (2 h/day for 7-8 weeks) resulted in decreases in the amounts of farnesylated p21Ras in these animals. Increased farnesylated p21Ras in hyperinsulinaemic animals reflected increasing increments in the activity of FTase in ob/ob mice (2-fold increase) and fa/fa Zucker rats (3.5-fold increase), while the total amounts of Ras proteins remained unchanged. In contrast to insulin-resistant hyperinsulinaemic animals, denervated insulin-resistant rat soleus muscle (in the presence of normoinsulinaemia) showed normal amounts of farnesylated p21Ras. In summary, these data confirm increased amounts of farnesylated p21Ras in tissues of hyperinsulinaemic animals.

  15. Influence of glutathione S-transferase A1, P1, M1, T1 polymorphisms on oral busulfan pharmacokinetics in children with congenital hemoglobinopathies undergoing hematopoietic stem cell transplantation.

    PubMed

    Elhasid, Ronit; Krivoy, Norberto; Rowe, Jacob M; Sprecher, Eli; Adler, Lior; Elkin, Hela; Efrati, Edna

    2010-12-01

    Busulfan (BU), often used in high dose for myeloablation before hematopoietic stem cell transplantation (HSCT), has been implicated in certain HSCT toxicities, including the occurrence of hepatic veno-occlusive disease (HVOD). In addition to weight and age, gene polymorphisms in specific members of the glutathione-transferase (GST) gene family (A1, P1, M1, and T1), involved in BU metabolism, may play a role in the wide inter-patient variability in systemic BU concentrations. The present study integrated clinical data regarding the occurrence of HVOD, graft versus host disease (GVHD), BU pharmacokinetics and GSTA1, GSTP1, GSTM1, and GSTT1 genotypes of 18 children who received BU in their pre-HSCT conditioning regimen. The children were all treated for congenital hemoglobinopathies and were all of Arab Moslem descent. The data demonstrate an association between GSTA1 and GSTP1 genotypes and BU-maximal concentration (C(max)) (P = 0.01, P = 0.02, respectively), area under the concentration-time curve (AUC) (P = 0.02, P = 0.01, respectively) and oral BU clearance/kg body weight (P < 0.02, P = 0.08, respectively). GSTM1-null individuals demonstrated lower BU-AUC/Kg compared to GSTM1-positive individuals. In addition, an association between GVHD and GSTM1-null genotype was found. GSTA1, GSTP1, and GSTM1 genotyping prior to HSCT in children with congenital hemoglobinopathies may allow better prediction of oral BU kinetics and the need for BU dose adjustment, as well as prediction of transplant related toxicity such as GVHD, thereby improving clinical outcome.

  16. Farnesyl pyrophosphate synthase modulators: a patent review (2006 - 2010)

    PubMed Central

    Sun, Shuting; McKenna, Charles E.

    2012-01-01

    Introduction Farnesyl pyrophosphosphate synthase (FPPS (also known as farnesyl diphosphate synthase, FDPS)) is one of the key enzymes involved in the mevalonate pathway and as such is widely expressed. FPPS modulators, specifically FPPS inhibitors, are useful in treating a number of diseases, including bone related disorders characterized by excessive bone resorption e.g. osteoporosis, cancer metathesis to bone and infectious diseases caused by certain parasites. Areas covered This review covers structures and applications of novel FPPS modulators described in the patent literature from 2006 to 2010. Patents disclosing new formulations and uses of existing FPPS inhibitors are also reviewed. Thirty-three patents retrieved from the USPTO, EP and WIPO databases are examined with the goal of defining current trends in drug discovery related to FPPS inhibition, and its therapeutic effects. Expert opinion Bisphosphonates continue to dominate in this area, although other types of modulator are making their appearance. Remarkable for their high bone mineral affinity, bisphosphonates are structural mimics of the dimethylallyl pyrophosphate (DMAPP) substrate of FPPS, and constitute the major type of FPPS inhibitor currently used in the clinic for treatment of bone-related diseases. Lipophilic bisphosphonates and new classes of non-bisphosphonate FPPS inhibitors (salicylic acid and quinoline derivatives) have been introduced as possible alternatives for treatment of soft tissue diseases, such as some cancers. Novel formulations, fluorescent diagnostic probes and new therapeutic applications of existing FPPS inhibitors are also areas of significant patent activity, demonstrating growing recognition of the versatility and underdeveloped potential of these drugs. PMID:21702715

  17. v-K-ras leads to preferential farnesylation of p21ras in FRTL-5 cells: Multiple interference with the isoprenoid pathway

    PubMed Central

    Laezza, Chiara; Di Marzo, Vincenzo; Bifulco, Maurizio

    1998-01-01

    The isoprenoid pathway in FRTL-5 thyroid cells was found to be deeply altered on transformation with v-K-ras. A dramatic overall reduction of protein prenylation was found in v-K-ras-transformed cells in comparison with the parent FRTL-5 cells, as shown by labeling cells with [3H]mevalonic acid. This phenomenon was accompanied by a relative increase of p21ras farnesylation and by a decrease of the ratio between the amounts of geranylgeraniol and farnesol bound to prenylated proteins. Analysis of protein prenylation in FRTL-5 cells transformed by a temperature-sensitive mutant of the v-K-ras oncogene indicated that these variations represent an early and specific marker of active K-ras. Conversely, FRTL-5 cells transformed with Harvey-ras showed a pattern of [3H]-mevalonate (MVA)-labeled proteins similar to that of nontransformed cells. The K-ras oncogene activation also resulted in an overall decrease of [3H]-MVA incorporation into isopentenyl-tRNA together with an increase of unprocessed [3H]-MVA and no alteration in [3H]-MVA uptake. The effects of v-K-ras on protein prenylation could be mimicked in FRTL-5 cells by lowering the concentration of exogenous [3H]-MVA whereas increasing the [3H]-MVA concentration did not revert the alterations observed in transformed cells. Accordingly, v-K-ras expression was found to: (i) down-regulate mevalonate kinase; (ii) induce farnesyl-pyrophosphate synthase expression; and (iii) augment protein farnesyltransferase but not protein geranylgeranyl-transferase-I activity. Among these events, mevalonate kinase down-regulation appeared to be related strictly to differential protein prenylation. This study represents an example of how expression of the v-K-ras oncogene, through multiple interferences with the isoprenoid metabolic pathway, may result in the preferential farnesylation of the ras oncogene product p21ras. PMID:9811854

  18. Mechanisms of Membrane Binding of Small GTPase K-Ras4B Farnesylated Hypervariable Region*

    PubMed Central

    Jang, Hyunbum; Abraham, Sherwin J.; Chavan, Tanmay S.; Hitchinson, Ben; Khavrutskii, Lyuba; Tarasova, Nadya I.; Nussinov, Ruth; Gaponenko, Vadim

    2015-01-01

    K-Ras4B belongs to a family of small GTPases that regulates cell growth, differentiation and survival. K-ras is frequently mutated in cancer. K-Ras4B association with the plasma membrane through its farnesylated and positively charged C-terminal hypervariable region (HVR) is critical to its oncogenic function. However, the structural mechanisms of membrane association are not fully understood. Here, using confocal microscopy, surface plasmon resonance, and molecular dynamics simulations, we observed that K-Ras4B can be distributed in rigid and loosely packed membrane domains. Its membrane binding domain interaction with phospholipids is driven by membrane fluidity. The farnesyl group spontaneously inserts into the disordered lipid microdomains, whereas the rigid microdomains restrict the farnesyl group penetration. We speculate that the resulting farnesyl protrusion toward the cell interior allows oligomerization of the K-Ras4B membrane binding domain in rigid microdomains. Unlike other Ras isoforms, K-Ras4B HVR contains a single farnesyl modification and positively charged polylysine sequence. The high positive charge not only modulates specific HVR binding to anionic phospholipids but farnesyl membrane orientation. Phosphorylation of Ser-181 prohibits spontaneous farnesyl membrane insertion. The mechanism illuminates the roles of HVR modifications in K-Ras4B targeting microdomains of the plasma membrane and suggests an additional function for HVR in regulation of Ras signaling. PMID:25713064

  19. Trypanosoma brucei prenylated-protein carboxyl methyltransferase prefers farnesylated substrates.

    PubMed Central

    Buckner, Frederick S; Kateete, David P; Lubega, George W; Van Voorhis, Wesley C; Yokoyama, Kohei

    2002-01-01

    Carboxyl methylation of the C-terminal prenylated cysteine, which occurs in most farnesylated and geranylgeranylated proteins, is a reversible step and is implicated in the regulation of membrane binding and cellular functions of prenylated proteins such as GTPases. The gene coding for prenylated-protein carboxyl methyltransferase (PPMT) of the protozoan parasite Trypanosoma brucei has been cloned and expressed in the baculovirus/Sf9 cell system. The protein of 245 amino acids has 24-28% sequence identity to the orthologues from other species including human and Saccharomyces cerevisiae. Methyltransferase activity was detected in the membrane fraction from Sf9 cells infected with the recombinant baculovirus using N -acetyl- S -farnesylcysteine (AFC) and S -adenosyl[ methyl -(3)H]methionine ([(3)H]AdoMet) as substrates. Recombinant T. brucei PPMT prefers AFC to N -acetyl- S -geranylgeranylcysteine (AGGC) by 10-50-fold based on the V (max)/ K (m) values. Native PPMT activity detected in the membrane fraction from T. brucei procyclics displays similar substrate specificity ( approximately 40-fold preference for AFC over AGGC). In contrast, mouse liver PPMT utilizes both AFC and AGGC as substrates with similar catalytic efficiencies. Several cellular proteins of the T. brucei bloodstream form were shown to be carboxyl methylated in a cell-free system. Incorporation of [(3)H]methyl group from [(3)H]AdoMet into most of the proteins was significantly inhibited by AFC but not AGGC at 20 microM, suggesting that T. brucei PPMT acts on farnesylated proteins in the cell. Cells of the T. brucei bloodstream form show higher sensitivity to AFC and AGGC (EC(50)=70-80 microM) compared with mouse 3T3 cells (EC(50)>150 microM). PMID:12141948

  20. Effects of farnesyl pyrophosphate accumulation on calvarial osteoblast differentiation.

    PubMed

    Weivoda, Megan M; Hohl, Raymond J

    2011-08-01

    Statins, drugs commonly used to lower serum cholesterol, have been shown to stimulate osteoblast differentiation and bone formation. Statins inhibit 3-hydroxy-3-methylglutaryl (HMG)-coenzyme A reductase (HMGCR), the first step of the isoprenoid biosynthetic pathway, leading to the depletion of the isoprenoids farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). The effects of statins on bone have previously been attributed to the depletion of GGPP, because the addition of exogenous GGPP prevented statin-stimulated osteoblast differentiation in vitro. However, in a recent report, we demonstrated that the specific depletion of GGPP did not stimulate but, in fact, inhibited osteoblast differentiation. This led us to hypothesize that isoprenoids upstream of GGPP play a role in the regulation of osteoblast differentiation. We demonstrate here that the expression of HMGCR and FPP synthase decreased during primary calvarial osteoblast differentiation, correlating with decreased FPP and GGPP levels during differentiation. Zaragozic acid (ZGA) inhibits the isoprenoid biosynthetic pathway enzyme squalene synthase, leading to an accumulation of the squalene synthase substrate FPP. ZGA treatment of calvarial osteoblasts led to a significant increase in intracellular FPP and resulted in inhibition of osteoblast differentiation as measured by osteoblastic gene expression, alkaline phosphatase activity, and matrix mineralization. Simultaneous HMGCR inhibition prevented the accumulation of FPP and restored osteoblast differentiation. In contrast, specifically inhibiting GGPPS to lower the ZGA-induced increase in GGPP did not restore osteoblast differentiation. The specificity of HMGCR inhibition to restore osteoblast differentiation of ZGA-treated cultures through the reduction in isoprenoid accumulation was confirmed with the addition of exogenous mevalonate. Similar to ZGA treatment, exogenous FPP inhibited the mineralization of primary calvarial osteoblasts

  1. Ras protein of the slime mold Physarum polycephalum is farnesylated in vitro.

    PubMed

    Talarczyk, E; Hung, V S; Kozlowski, P; Trzcinska-Danielewicz, J; Swiezewska, E

    1999-01-01

    Physarum Ppras1 protein was efficiently prenylated by prenyltransferases of spinach. Surprisingly in spite of the C-terminal sequence (CLLL) specific for geranylgeranylation the protein was preferentially farnesylated. Consequences of this observation are discussed.

  2. Inhibiting farnesylation of progerin prevents the characteristic nuclear blebbing of Hutchinson-Gilford progeria syndrome.

    PubMed

    Capell, Brian C; Erdos, Michael R; Madigan, James P; Fiordalisi, James J; Varga, Renee; Conneely, Karen N; Gordon, Leslie B; Der, Channing J; Cox, Adrienne D; Collins, Francis S

    2005-09-06

    Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder that is characterized by dramatic premature aging and accelerated cardiovascular disease. HGPS is almost always caused by a de novo point mutation in the lamin A gene (LMNA) that activates a cryptic splice donor site, producing a truncated mutant protein termed "progerin." WT prelamin A is anchored to the nuclear envelope by a farnesyl isoprenoid lipid. Cleavage of the terminal 15 aa and the farnesyl group releases mature lamin A from this tether. In contrast, this cleavage site is deleted in progerin. We hypothesized that retention of the farnesyl group causes progerin to become permanently anchored in the nuclear membrane, disrupting proper nuclear scaffolding and causing the characteristic nuclear blebbing seen in HGPS cells. Also, we hypothesized that blocking farnesylation would decrease progerin toxicity. To test this hypothesis, the terminal CSIM sequence in progerin was mutated to SSIM, a sequence that cannot be farnesylated. SSIM progerin relocalized from the nuclear periphery into nucleoplasmic aggregates and produced no nuclear blebbing. Also, blocking farnesylation of authentic progerin in transiently transfected HeLa, HEK 293, and NIH 3T3 cells with farnesyltransferase inhibitors (FTIs) restored normal nuclear architecture. Last, treatment of both early- and late-passage human HGPS fibroblasts with FTIs resulted in significant reductions in nuclear blebbing. Our results suggest that treatment with FTIs represents a potential therapy for patients with HGPS.

  3. Human Lamin B Contains a Farnesylated Cysteine Residue*

    PubMed Central

    Farnsworth, Christopher C.; Wolda, Sharon L.; Gelb, Michael H.; Glomset, John A.

    2012-01-01

    We recently showed that HeLa cell lamin B is modified by a mevalonic acid derivative. Here we identified the modified amino acid, determined its mode of link-age to the mevalonic acid derivative, and established the derivative’s structure. A cysteine residue is modified because experiments with lamin B that had been biosynthetically labeled with [3H] mevalonic acid or [35S] cysteine and then extensively digested with proteases yielded 3H- or 35S-labeled products that co-chromatographed in five successive systems. A thioether linkage rather than a thioester linkage is involved because the mevalonic acid derivative could be released from the 3H-labeled products in a pentane-extractable form by treatment with Raney nickel but not with methanolic KOH. The derivative is a farnesyl moiety because the Raney nickel-released material was identified as 2,6,10-trimethyl-2,6,10-dodecatriene by a combination of gas chromatography and mass spectrometry. The thioether-modified cysteine residue appears to be located near the carboxyl end of lamin B because treatment of 3H-labeled lamin B with cyanogen bromide yielded a single labeled polypeptide that mapped toward this end of the cDNA-inferred sequence of human lamin B. PMID:2684976

  4. Isopentenyl Pyrophosphate cis-1,4-Polyisoprenyl Transferase from Guayule (Parthenium argentatum Gray) 1

    PubMed Central

    Madhavan, S.; Benedict, Chauncey R.

    1984-01-01

    Electron micrographs of the mesophyll cells of guayule Parthenium argentatum Gray leaves show deposits of cis-polyisoprene (rubber) in the cytoplasm in the vicinity of mitochondria and chloroplasts and demonstrate that the rubber-synthesizing enzymes are present in guayule leaves. The terminal step in the synthesis of cis-polyisoprene from isopentenyl pyrophosphate (IPP) catalyzed by isopentenyl pyrophosphate cis-1,4-polyisoprenyl transferase has been demonstrated in crude leaf extracts by the enzymic incorporation of [14C]isopentenyl pyrophosphate into the polymer and the recovery of [14C]levulinic acid following ozonolysis. The rubber transferase activity in the crude extracts of guayule leaves was 5.8 nanomoles isopentenyl pyrophosphate incorporated per milligram protein per hour. This is the first description of the rubber transferase from a nonlaticiferous plant. The specific activity (in units of nanomoles IPP converted per milligram protein per hour) of the partially purified enzyme following chromatography on diethylaminoethyl-cellulose columns was 41.7 units and contained 0.29 units of IPP isomerase activity and 0.08 units of farnesyl pyrophosphate synthetase activity. The rubber transferase requires reduced glutathione and Mg2+ for maximal activity. There was no incorporation of IPP into cis-1,4-polyisoprene in the absence of rubber particles as primer, and Langmuir isotherm plots showed that the specific activity of the enzyme was proportional to the concentration of the enzyme on the surface of the rubber particles. For a given rubber particle distribution, enzyme activity was proportional to time, IPP concentration, and rubber concentration. The addition of 0.4 millimolar dimethylallyl pyrophosphate to the rubber transferase reaction resulted in a 2-fold increase in the incorporation of IPP into rubber. A comparison was made of the relative activities of rubber transferase in different species of Parthenium, Ficus, and Euphorbia. Images Fig. 2 Fig. 3

  5. Isopentenyl Pyrophosphate cis-1,4-Polyisoprenyl Transferase from Guayule (Parthenium argentatum Gray).

    PubMed

    Madhavan, S; Benedict, C R

    1984-08-01

    Electron micrographs of the mesophyll cells of guayule Parthenium argentatum Gray leaves show deposits of cis-polyisoprene (rubber) in the cytoplasm in the vicinity of mitochondria and chloroplasts and demonstrate that the rubber-synthesizing enzymes are present in guayule leaves. The terminal step in the synthesis of cis-polyisoprene from isopentenyl pyrophosphate (IPP) catalyzed by isopentenyl pyrophosphate cis-1,4-polyisoprenyl transferase has been demonstrated in crude leaf extracts by the enzymic incorporation of [(14)C]isopentenyl pyrophosphate into the polymer and the recovery of [(14)C]levulinic acid following ozonolysis. The rubber transferase activity in the crude extracts of guayule leaves was 5.8 nanomoles isopentenyl pyrophosphate incorporated per milligram protein per hour. This is the first description of the rubber transferase from a nonlaticiferous plant.The specific activity (in units of nanomoles IPP converted per milligram protein per hour) of the partially purified enzyme following chromatography on diethylaminoethyl-cellulose columns was 41.7 units and contained 0.29 units of IPP isomerase activity and 0.08 units of farnesyl pyrophosphate synthetase activity. The rubber transferase requires reduced glutathione and Mg(2+) for maximal activity. There was no incorporation of IPP into cis-1,4-polyisoprene in the absence of rubber particles as primer, and Langmuir isotherm plots showed that the specific activity of the enzyme was proportional to the concentration of the enzyme on the surface of the rubber particles. For a given rubber particle distribution, enzyme activity was proportional to time, IPP concentration, and rubber concentration. The addition of 0.4 millimolar dimethylallyl pyrophosphate to the rubber transferase reaction resulted in a 2-fold increase in the incorporation of IPP into rubber. A comparison was made of the relative activities of rubber transferase in different species of Parthenium, Ficus, and Euphorbia.

  6. Allosteric modulation of peroxisomal membrane protein recognition by farnesylation of the peroxisomal import receptor PEX19

    PubMed Central

    Emmanouilidis, Leonidas; Schütz, Ulrike; Tripsianes, Konstantinos; Madl, Tobias; Radke, Juliane; Rucktäschel, Robert; Wilmanns, Matthias; Schliebs, Wolfgang; Erdmann, Ralf; Sattler, Michael

    2017-01-01

    The transport of peroxisomal membrane proteins (PMPs) requires the soluble PEX19 protein as chaperone and import receptor. Recognition of cargo PMPs by the C-terminal domain (CTD) of PEX19 is required for peroxisome biogenesis in vivo. Farnesylation at a C-terminal CaaX motif in PEX19 enhances the PMP interaction, but the underlying molecular mechanisms are unknown. Here, we report the NMR-derived structure of the farnesylated human PEX19 CTD, which reveals that the farnesyl moiety is buried in an internal hydrophobic cavity. This induces substantial conformational changes that allosterically reshape the PEX19 surface to form two hydrophobic pockets for the recognition of conserved aromatic/aliphatic side chains in PMPs. Mutations of PEX19 residues that either mediate farnesyl contacts or are directly involved in PMP recognition abolish cargo binding and cannot complement a ΔPEX19 phenotype in human Zellweger patient fibroblasts. Our results demonstrate an allosteric mechanism for the modulation of protein function by farnesylation. PMID:28281558

  7. ASG2 is a farnesylated DWD protein that acts as ABA negative regulator in Arabidopsis.

    PubMed

    Dutilleul, Christelle; Ribeiro, Iliana; Blanc, Nathalie; Nezames, Cynthia D; Deng, Xing Wang; Zglobicki, Piotr; Palacio Barrera, Ana María; Atehortùa, Lucia; Courtois, Martine; Labas, Valérie; Giglioli-Guivarc'h, Nathalie; Ducos, Eric

    2016-01-01

    The tagging-via-substrate approach designed for the capture of mammal prenylated proteins was adapted to Arabidopsis cell culture. In this way, proteins are in vivo tagged with an azide-modified farnesyl moiety and captured thanks to biotin alkyne Click-iT® chemistry with further streptavidin-affinity chromatography. Mass spectrometry analyses identified four small GTPases and ASG2 (ALTERED SEED GERMINATION 2), a protein previously associated to the seed germination gene network. ASG2 is a conserved protein in plants and displays a unique feature that associates WD40 domains and tetratricopeptide repeats. Additionally, we show that ASG2 has a C-terminal CaaX-box that is farnesylated in vitro. Protoplast transfections using CaaX prenyltransferase mutants show that farnesylation provokes ASG2 nucleus exclusion. Moreover, ASG2 interacts with DDB1 (DAMAGE DNA BINDING protein 1), and the subcellular localization of this complex depends on ASG2 farnesylation status. Finally, germination and root elongation experiments reveal that asg2 and the farnesyltransferase mutant era1 (ENHANCED RESPONSE TO ABSCISIC ACID (ABA) 1) behave in similar manners when exposed to ABA or salt stress. To our knowledge, ASG2 is the first farnesylated DWD (DDB1 binding WD40) protein related to ABA response in Arabidopsis that may be linked to era1 phenotypes.

  8. Farnesyl Diphosphate Analogues with Aryl Moieties are Efficient Alternate Substrates for Protein Farnesyltransferase

    PubMed Central

    Subramanian, Thangaiah; Pais, June E.; Liu, Suxia; Troutman, Jerry M.; Suzuki, Yuta; Subramanian, Karunai Leela; Fierke, Carol; Andres, Douglas A.; Spielmann, H. Peter

    2012-01-01

    Farnesylation is an important post-translational modification essential for proper localization and function of many proteins. Transfer of the farnesyl group from farnesyl diphosphate (FPP) to proteins is catalyzed by protein farnesyltransferase (FTase). We employed a library of FPP analogues with a range of aryl groups substituting for individual isoprene moieties to examine some of the structural and electronic properties of analogue transfer to peptide catalyzed by FTase. Analysis of steady-state kinetics for modification of peptide substrates revealed that the multiple turnover activity depends on the analogue structure. Analogues where the first isoprene is replaced by a benzyl group and an analogue where each isoprene is replaced by an aryl group are good substrates. In sharp contrast with the steady-state reaction, the single turnover rate constant for dansyl-GCVLS alkylation was found to be the same for all analogues, despite the increased chemical reactivity of the benzyl analogues and the increased steric bulk of other analogues. However, the single turnover rate constant for alkylation does depend on the Ca1a2X peptide sequence. These results suggest that the isoprenoid transition state conformation is preferred over the inactive E•FPP• Ca1a2X ternary complex conformation. Furthermore, these data suggest that the farnesyl binding site in the exit groove may be significantly more selective for the farnesyl diphosphate substrate than the active site binding pocket and therefore might be a useful site for design of novel inhibitors. PMID:22989235

  9. Generation of self-clusters of galectin-1 in the farnesyl-bound form

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Kazumi; Niwa, Yusuke; Nakabayashi, Takakazu; Hiramatsu, Hirotsugu

    2016-09-01

    Ras protein is involved in a signal transduction cascade in cell growth, and cluster formation of H-Ras and human galectin-1 (Gal-1) complex is considered to be crucial to achieve its physiological roles. It is considered that the complex is formed through interactions between Gal-1 and the farnesyl group (farnesyl-dependent model), post-translationally modified to the C-terminal Cys, of H-Ras. We investigated the role of farnesyl-bound Gal-1 in the cluster formation by analyzing the structure and properties of Gal-1 bound to farnesyl thiosalicylic acid (FTS), a competitive inhibitor of the binding of H-Ras to Gal-1. Gal-1 exhibited self-cluster formation upon interaction with FTS, and small- and large-size clusters were formed depending on FTS concentration. The galactoside-binding pocket of Gal-1 in the FTS-bound form was found to play an important role in small-size cluster formation. Large-size clusters were likely formed by the interaction among the hydrophobic sites of Gal-1 in the FTS-bound form. The present results indicate that Gal-1 in the FTS-bound form has the ability to form self-clusters as well as intrinsic lectin activity. Relevance of the self-clustering of FTS-bound Gal-1 to the cluster formation of the H-Ras-Gal-1complex was discussed by taking account of the farnesyl-dependent model and another (Raf-dependent) model.

  10. Plant glutathione transferases

    PubMed Central

    Dixon, David P; Lapthorn, Adrian; Edwards, Robert

    2002-01-01

    The soluble glutathione transferases (GSTs, EC 2.5.1.18) are encoded by a large and diverse gene family in plants, which can be divided on the basis of sequence identity into the phi, tau, theta, zeta and lambda classes. The theta and zeta GSTs have counterparts in animals but the other classes are plant-specific and form the focus of this article. The genome of Arabidopsis thaliana contains 48 GST genes, with the tau and phi classes being the most numerous. The GST proteins have evolved by gene duplication to perform a range of functional roles using the tripeptide glutathione (GSH) as a cosubstrate or coenzyme. GSTs are predominantly expressed in the cytosol, where their GSH-dependent catalytic functions include the conjugation and resulting detoxification of herbicides, the reduction of organic hydroperoxides formed during oxidative stress and the isomerization of maleylacetoacetate to fumarylacetoacetate, a key step in the catabolism of tyrosine. GSTs also have non-catalytic roles, binding flavonoid natural products in the cytosol prior to their deposition in the vacuole. Recent studies have also implicated GSTs as components of ultraviolet-inducible cell signaling pathways and as potential regulators of apoptosis. Although sequence diversification has produced GSTs with multiple functions, the structure of these proteins has been highly conserved. The GSTs thus represent an excellent example of how protein families can diversify to fulfill multiple functions while conserving form and structure. PMID:11897031

  11. Computational Insights into Binding of Bisphosphates to Farnesyl Pyrophosphate Synthase

    PubMed Central

    Ohno, K; Mori, K; Orita, M; Takeuchi, M

    2011-01-01

    Bisphosphonates (BPs) are the most widely used and effective treatment for osteoporosis and Paget's disease. Non-nitrogen containing BPs (non-N-BPs), namely etidronate, clodronate, tiludronate, as well as nitrogen-containing BPs (N-BPs), namely pamidronate, alendronate, ibandronate, risedronate, zoledronate and minodronate have been launched on the market to date. N-BPs act by inhibiting the enzyme farnesyl pyrophosphate synthase (FPPS), and several crystal structures of complexes between FPPS and N-BPs have been revealed. Understanding the physical basis of the binding between protein and small molecules is an important goal in both medicinal chemistry and structural biology. In this review, we analyze in detail the energetic basis of molecular recognition between FPPS and N-BPs. First, we summarize the interactions between ligands and proteins observed in N-BPs-FPPS complexes in the Protein Data Bank (PDB). Second, we present an interaction energy analysis on the basis of full quantum mechanical calculation of FPPS and N-BP complexes using the fragment molecular orbital (FMO) method. The FMO result revealed that not only hydrogen bond and electrostatic interaction but also CH-O and π-π interaction with FPPS are important for N-BP’s potency. Third, we describe a binding site analysis of FPPS on the basis of the inhomogeneous solvation theory which, by clustering the results from an explicit solvent molecular dynamics simulation (MD), is capable of describing the entropic and enthalpic contributions to the free energies of individual hydration sites. Finally, we also discuss the structure-activity relationship (SAR) of the series of minodronate derivatives. PMID:21110804

  12. Towards Complete Sets of Farnesylated and Geranylgeranylated Proteins

    PubMed Central

    Maurer-Stroh, Sebastian; Koranda, Manfred; Benetka, Wolfgang; Schneider, Georg; Sirota, Fernanda L; Eisenhaber, Frank

    2007-01-01

    selective farnesylation of targets with an evolutionary conserved modification site. PMID:17411337

  13. An accumulation of non-farnesylated prelamin A causes cardiomyopathy but not progeria.

    PubMed

    Davies, Brandon S J; Barnes, Richard H; Tu, Yiping; Ren, Shuxun; Andres, Douglas A; Spielmann, H Peter; Lammerding, Jan; Wang, Yibin; Young, Stephen G; Fong, Loren G

    2010-07-01

    Lamin A is formed from prelamin A by four post-translational processing steps-farnesylation, release of the last three amino acids of the protein, methylation of the farnesylcysteine and the endoproteolytic release of the C-terminal 15 amino acids (including the farnesylcysteine methyl ester). When the final processing step does not occur, a farnesylated and methylated prelamin A accumulates in cells, causing a severe progeroid disease, restrictive dermopathy (RD). Whether RD is caused by the retention of farnesyl lipid on prelamin A, or by the retention of the last 15 amino acids of the protein, is unknown. To address this issue, we created knock-in mice harboring a mutant Lmna allele (LmnanPLAO) that yields exclusively non-farnesylated prelamin A (and no lamin C). These mice had no evidence of progeria but succumbed to cardiomyopathy. We suspected that the non-farnesylated prelamin A in the tissues of these mice would be strikingly mislocalized to the nucleoplasm, but this was not the case; most was at the nuclear rim (indistinguishable from the lamin A in wild-type mice). The cardiomyopathy could not be ascribed to an absence of lamin C because mice expressing an otherwise identical knock-in allele yielding only wild-type prelamin A appeared normal. We conclude that lamin C synthesis is dispensable in mice and that the failure to convert prelamin A to mature lamin A causes cardiomyopathy (at least in the absence of lamin C). The latter finding is potentially relevant to the long-term use of protein farnesyltransferase inhibitors, which lead to an accumulation of non-farnesylated prelamin A.

  14. Characterization of oligosaccharyl transferase

    SciTech Connect

    Kaplan, H.A.; Lennarz, W.J.

    1987-05-01

    Oligosaccharyl transferase (OT), the enzyme catalyzing the transfer of oligosaccharide from dolichol-PP-GlcNAc2Man9Glc3 to asparagine residues of -Asn-X-Thr/Ser- sequences in nascent polypeptides, was characterized in hen oviduct microsomes using an active site-directed photoaffinity probe, N/sup /-( SVI)-3-(4-hydroxyphenylpropionyl)-Asn-Lys(N/sup epsilon/-p-azidobenzoyl)-Thr-NH2. Kinetic experiments revealed that the labeled probe interacted with a 57 kDa Coomassie Blue stainable protein at short incubation intervals; the radioactive probe was found linked to a 60 kDa protein after longer incubations. Endo H digestion of the 60 kDa SVI-photolabeled OT decreased the molecular mass to 57 kDa. The 57 kDa Coomassie Blue stainable protein was not endo H sensitive. When dolichol-PP-oligosaccharide was depleted by preincubating the microsomes with excess acceptor peptide, only the 57 kDa SVI-labeled OT was formed. These data suggest that 1) OT is a 57 kDa protein, and 2) the appearance of the 60 kDa SVI-labeled OT is the result of covalent attachment of glycosylated tripeptide probe. The molecular mass of photolabeled OT was found to be similar in a variety of eukaryotes except in yeast, where it was larger. OT isolated by liquid chromatographic and 2-D gel electrophoretic techniques was used as immunogen to prepare monospecific polyclonal antisera. The specificity of the antibody was based on its ability to 1) recognize OT by immunblotting following electrophoretic transfer to nitrocellulose, 2) immunoprecipitate photolabeled enzyme, and 3) block active-site photolabeling of the enzyme.

  15. Biosynthesis of isoprenoids in Escherichia coli: stereochemistry of the reaction catalyzed by farnesyl diphosphate synthase.

    PubMed

    Leyes, A E; Baker, J A; Poulter, C D

    1999-10-07

    [formula: see text] Farnesyl diphosphate (FPP) synthase from Escherichia coli catalyzes the condensation of isopentenyl diphosphate (IPP) and geranyl diphosphate (GPP) with selective removal of the pro-R hydrogen at C2 of IPP, the same stereochemistry observed for the pig liver, yeast, and avian enzymes.

  16. Coordinated cell motility is regulated by a combination of LKB1 farnesylation and kinase activity

    PubMed Central

    Wilkinson, S.; Hou, Y.; Zoine, J. T.; Saltz, J.; Zhang, C.; Chen, Z.; Cooper, L. A. D.; Marcus, A. I.

    2017-01-01

    Cell motility requires the precise coordination of cell polarization, lamellipodia formation, adhesion, and force generation. LKB1 is a multi-functional serine/threonine kinase that associates with actin at the cellular leading edge of motile cells and suppresses FAK. We sought to understand how LKB1 coordinates these multiple events by systematically dissecting LKB1 protein domain function in combination with live cell imaging and computational approaches. We show that LKB1-actin colocalization is dependent upon LKB1 farnesylation leading to RhoA-ROCK-mediated stress fiber formation, but membrane dynamics is reliant on LKB1 kinase activity. We propose that LKB1 kinase activity controls membrane dynamics through FAK since loss of LKB1 kinase activity results in morphologically defective nascent adhesion sites. In contrast, defective farnesylation mislocalizes nascent adhesion sites, suggesting that LKB1 farnesylation serves as a targeting mechanism for properly localizing adhesion sites during cell motility. Together, we propose a model where coordination of LKB1 farnesylation and kinase activity serve as a multi-step mechanism to coordinate cell motility during migration. PMID:28102310

  17. Autophagic degradation of farnesylated prelamin A as a therapeutic approach to lamin-linked progeria.

    PubMed

    Cenni, V; Capanni, C; Columbaro, M; Ortolani, M; D'Apice, M R; Novelli, G; Fini, M; Marmiroli, S; Scarano, E; Maraldi, N M; Squarzoni, S; Prencipe, S; Lattanzi, G

    2011-10-19

    Farnesylated prelamin A is a processing intermediate produced in the lamin A maturation pathway. Accumulation of a truncated farnesylated prelamin A form, called progerin, is a hallmark of the severe premature ageing syndrome, Hutchinson-Gilford progeria. Progerin elicits toxic effects in cells, leading to chromatin damage and cellular senescence and ultimately causes skin and endothelial defects, bone resorption, lipodystrophy and accelerated ageing. Knowledge of the mechanism underlying prelamin A turnover is critical for the development of clinically effective protein inhibitors that can avoid accumulation to toxic levels without impairing lamin A/C expression, which is essential for normal biological functions. Little is known about specific molecules that may target farnesylated prelamin A to elicit protein degradation. Here, we report the discovery of rapamycin as a novel inhibitor of progerin, which dramatically and selectively decreases protein levels through a mechanism involving autophagic degradation. Rapamycin treatment of progeria cells lowers progerin, as well as wild-type prelamin A levels, and rescues the chromatin phenotype of cultured fibroblasts, including histone methylation status and BAF and LAP2alpha distribution patterns. Importantly, rapamycin treatment does not affect lamin C protein levels, but increases the relative expression of the prelamin A endoprotease ZMPSTE24. Thus, rapamycin, an antibiotic belonging to the class of macrolides, previously found to increase longevity in mouse models, can serve as a therapeutic tool, to eliminate progerin, avoid farnesylated prelamin A accumulation, and restore chromatin dynamics in progeroid laminopathies.

  18. An enzyme-coupled continuous fluorescence assay for farnesyl diphosphate synthases.

    PubMed

    Dozier, Jonathan K; Distefano, Mark D

    2012-02-01

    Farnesyl diphosphate synthase (FDPS) catalyzes the conversion of isopentenyl diphosphate and dimethylallyl diphosphate to farnesyl diphosphate, a crucial metabolic intermediate in the synthesis of cholesterol, ubiquinone, and prenylated proteins; consequently, much effort has gone into developing inhibitors that target FDPS. Currently most FDPS assays either use radiolabeled substrates and are discontinuous or monitor pyrophosphate release and not farnesyl diphosphate (FPP) creation. Here we report the development of a continuous coupled enzyme assay for FDPS activity that involves the subsequent incorporation of the FPP product of that reaction into a peptide via the action of protein farnesyltransferase (PFTase). By using a dansylated peptide whose fluorescence quantum yield increases upon farnesylation, the rate of FDPS-catalyzed FPP production can be measured. We show that this assay is more sensitive than existing coupled assays, that it can be used to conveniently monitor FDPS activity in a 96-well plate format, and that it can reproduce IC(50) values for several previously reported FDPS inhibitors. This new method offers a simple, safe, and continuous method to assay FDPS activity that should greatly facilitate the screening of inhibitors of this important target.

  19. An enzyme-coupled continuous fluorescence assay for farnesyl diphosphate synthases

    PubMed Central

    Dozier, Jonathan K; Distefano, Mark D

    2012-01-01

    Farnesyl diphosphate synthase (FDPS) catalyzes the conversion of isopentenyl diphosphate and dimethylallyl diphosphate to farnesyl diphosphate, a crucial metabolic intermediate in the synthesis of cholesterol, ubiquinone and prenylated proteins; consequently, much effort has gone into developing inhibitors that target FDPS. Currently most FDPS assays use either radiolabeled substrates and are discontinuous, or monitor pyrophosphate release and not farnesyl diphosphate (FPP) creation. Here we report the development of a continuous coupled enzyme assay for FDPS activity that involves the subsequent incorporation of the FPP product of that reaction into a peptide via the action of protein farnesyltransferase (PFTase). By using a dansylated peptide whose fluorescence quantum yield increases upon farnesylation, the rate of FDPS-catalyzed FPP production can be measured. We show that this assay is more sensitive than existing coupled assays, that it can be used to conveniently monitor FDPS activity in a 96-well plate format and that it can reproduce IC50 values for several previously reported FDPS inhibitors. This new method offers a simple, safe and continuous method to assay FDPS activity that should greatly facilitate the screening of inhibitors of this important target. PMID:22085443

  20. Inhibition of Protein Farnesylation Arrests Adipogenesis and Affects PPARγ Expression and Activation in Differentiating Mesenchymal Stem Cells

    PubMed Central

    Rivas, Daniel; Akter, Rahima; Duque, Gustavo

    2007-01-01

    Protein farnesylation is required for the activation of multiple proteins involved in cell differentiation and function. In white adipose tissue protein, farnesylation has shown to be essential for the successful differentiation of preadipocytes into adipocytes. We hypothesize that protein farnesylation is required for PPARγ2 expression and activation, and therefore for the differentiation of human mesenchymal stem cells (MSCs) into adipocytes. MSCs were plated and induced to differentiate into adipocytes for three weeks. Differentiating cells were treated with either an inhibitor of farnesylation (FTI-277) or vehicle alone. The effect of inhibition of farnesylation in differentiating adipocytes was determined by oil red O staining. Cell survival was quantified using MTS Formazan. Additionally, nuclear extracts were obtained and prelamin A, chaperon protein HDJ-2, PPARγ, and SREBP-1 were determined by western blot. Finally, DNA binding PPARγ activity was determined using an ELISA-based PPARγ activation quantification method. Treatment with an inhibitor of farnesylation (FTI-277) arrests adipogenesis without affecting cell survival. This effect was concomitant with lower levels of PPARγ expression and activity. Finally, accumulation of prelamin A induced an increased proportion of mature SREBP-1 which is known to affect PPARγ activity. In summary, inhibition of protein farnesylation arrests the adipogenic differentiation of MSCs and affects PPARγ expression and activity. PMID:18274630

  1. Inhibition of Protein Farnesylation Arrests Adipogenesis and Affects PPARgamma Expression and Activation in Differentiating Mesenchymal Stem Cells.

    PubMed

    Rivas, Daniel; Akter, Rahima; Duque, Gustavo

    2007-01-01

    Protein farnesylation is required for the activation of multiple proteins involved in cell differentiation and function. In white adipose tissue protein, farnesylation has shown to be essential for the successful differentiation of preadipocytes into adipocytes. We hypothesize that protein farnesylation is required for PPARgamma2 expression and activation, and therefore for the differentiation of human mesenchymal stem cells (MSCs) into adipocytes. MSCs were plated and induced to differentiate into adipocytes for three weeks. Differentiating cells were treated with either an inhibitor of farnesylation (FTI-277) or vehicle alone. The effect of inhibition of farnesylation in differentiating adipocytes was determined by oil red O staining. Cell survival was quantified using MTS Formazan. Additionally, nuclear extracts were obtained and prelamin A, chaperon protein HDJ-2, PPARgamma, and SREBP-1 were determined by western blot. Finally, DNA binding PPARgamma activity was determined using an ELISA-based PPARgamma activation quantification method. Treatment with an inhibitor of farnesylation (FTI-277) arrests adipogenesis without affecting cell survival. This effect was concomitant with lower levels of PPARgamma expression and activity. Finally, accumulation of prelamin A induced an increased proportion of mature SREBP-1 which is known to affect PPARgamma activity. In summary, inhibition of protein farnesylation arrests the adipogenic differentiation of MSCs and affects PPARgamma expression and activity.

  2. Generation of self-clusters of galectin-1 in the farnesyl-bound form

    PubMed Central

    Yamaguchi, Kazumi; Niwa, Yusuke; Nakabayashi, Takakazu; Hiramatsu, Hirotsugu

    2016-01-01

    Ras protein is involved in a signal transduction cascade in cell growth, and cluster formation of H-Ras and human galectin-1 (Gal-1) complex is considered to be crucial to achieve its physiological roles. It is considered that the complex is formed through interactions between Gal-1 and the farnesyl group (farnesyl-dependent model), post-translationally modified to the C-terminal Cys, of H-Ras. We investigated the role of farnesyl-bound Gal-1 in the cluster formation by analyzing the structure and properties of Gal-1 bound to farnesyl thiosalicylic acid (FTS), a competitive inhibitor of the binding of H-Ras to Gal-1. Gal-1 exhibited self-cluster formation upon interaction with FTS, and small- and large-size clusters were formed depending on FTS concentration. The galactoside-binding pocket of Gal-1 in the FTS-bound form was found to play an important role in small-size cluster formation. Large-size clusters were likely formed by the interaction among the hydrophobic sites of Gal-1 in the FTS-bound form. The present results indicate that Gal-1 in the FTS-bound form has the ability to form self-clusters as well as intrinsic lectin activity. Relevance of the self-clustering of FTS-bound Gal-1 to the cluster formation of the H-Ras–Gal-1complex was discussed by taking account of the farnesyl-dependent model and another (Raf-dependent) model. PMID:27624845

  3. Molecular Cloning of Adenosinediphosphoribosyl Transferase.

    DTIC Science & Technology

    1987-09-08

    AD-RIB5 458 NOLECULNA CLONING OF AOENOSINEDXPNOSPHORIBOSyL 1/1 TRNSFERASEMU CAILIFORNIA UNIV SRN FRANCISCO E KUN US SEP 8? WFOSR-TR-87-0982 SWFOSR-B5...ACCESSION NO.D,. 03261102F 2312 A~5 11. TITLE (include Securqt Classification) 0 Molecular Cloning of Adenosinediphosphoribosyl Transferase 12. PERSONAL...I’:- AFOSR.Tlt. 8 7 - 0 9 8,2 0IL * pi AFOSR- 85 -0377 PROGRESS REPORT Molecular Cloning of Adenosinediphosphoribosyl Transferase 5." Period of

  4. Glutathione transferases and neurodegenerative diseases.

    PubMed

    Mazzetti, Anna Paola; Fiorile, Maria Carmela; Primavera, Alessandra; Lo Bello, Mario

    2015-03-01

    There is substantial agreement that the unbalance between oxidant and antioxidant species may affect the onset and/or the course of a number of common diseases including Parkinson's and Alzheimer's diseases. Many studies suggest a crucial role for oxidative stress in the first phase of aging, or in the pathogenesis of various diseases including neurological ones. Particularly, the role exerted by glutathione and glutathione-related enzymes (Glutathione Transferases) in the nervous system appears more relevant, this latter tissue being much more vulnerable to toxins and oxidative stress than other tissues such as liver, kidney or muscle. The present review addresses the question by focusing on the results obtained by specimens from patients or by in vitro studies using cells or animal models related to Parkinson's and Alzheimer's diseases. In general, there is an association between glutathione depletion and Parkinson's or Alzheimer's disease. In addition, a significant decrease of glutathione transferase activity in selected areas of brain and in ventricular cerebrospinal fluid was found. For some glutathione transferase genes there is also a correlation between polymorphisms and onset/outcome of neurodegenerative diseases. Thus, there is a general agreement about the protective effect exerted by glutathione and glutathione transferases but no clear answer about the mechanisms underlying this crucial role in the insurgence of neurodegenerative diseases.

  5. Identification of a quorum sensing pheromone posttranslationally farnesylated at the internal tryptophan residue from Bacillus subtilis subsp. natto.

    PubMed

    Hayashi, Shunsuke; Usami, Syohei; Nakamura, Yuta; Ozaki, Koki; Okada, Masahiro

    2015-01-01

    Bacillus subtilis subsp. natto produces poly-γ-glutamic acid under the control of quorum sensing. We identified ComXnatto pheromone as the quorum-sensing pheromone with an amino acid sequence of Lys-Trp-Pro-Pro-Ile-Glu and the tryptophan residue posttranslationally modified by a farnesyl group. ComXnatto pheromone is unique in the sense that the 5th tryptophan residue from the C-terminal is farnesylated.

  6. Human farnesyl pyrophosphate synthase is allosterically inhibited by its own product

    PubMed Central

    Park, Jaeok; Zielinski, Michal; Magder, Alexandr; Tsantrizos, Youla S.; Berghuis, Albert M.

    2017-01-01

    Farnesyl pyrophosphate synthase (FPPS) is an enzyme of the mevalonate pathway and a well-established therapeutic target. Recent research has focused around a newly identified druggable pocket near the enzyme's active site. Pharmacological exploitation of this pocket is deemed promising; however, its natural biological function, if any, is yet unknown. Here we report that the product of FPPS, farnesyl pyrophosphate (FPP), can bind to this pocket and lock the enzyme in an inactive state. The Kd for this binding is 5–6 μM, within a catalytically relevant range. These results indicate that FPPS activity is sensitive to the product concentration. Kinetic analysis shows that the enzyme is inhibited through FPP accumulation. Having a specific physiological effector, FPPS is a bona fide allosteric enzyme. This allostery offers an exquisite mechanism for controlling prenyl pyrophosphate levels in vivo and thus contributes an additional layer of regulation to the mevalonate pathway. PMID:28098152

  7. A novel role for farnesyl pyrophosphate synthase in fibroblast growth factor-mediated signal transduction.

    PubMed Central

    Reilly, John F; Martinez, Shawndra D; Mickey, Gregory; Maher, Pamela A

    2002-01-01

    Farnesyl pyrophosphate synthase (FPPS) catalyses the formation of a key cellular intermediate in isoprenoid metabolic pathways. Here we describe a novel role for this enzyme in fibroblast growth factor (FGF)-mediated signalling. We demonstrate the binding of FPPS to FGF receptors (FGFRs) using the yeast two-hybrid assay, pull-down assays and co-immunoprecipitation. The interaction between FPPS and FGFR is regulated by the cellular metabolic state and by treatment with FGF-2. Overexpression of FPPS inhibits FGF-2-induced cell proliferation, accompanied by a failure of the FGF-2-mediated induction of cyclins D1 and E. Overexpression of FPPS in fibroblasts also promotes increased farnesylation of Ras, and temporally extends FGF-2-stimulated activation of the Ras/ERK (extracellular-signal-regulated kinase) cascade. These data suggest that, in addition to its role in isoprenoid biosynthesis, FPPS may function as a modulator of the cellular response to FGF treatment. PMID:12020352

  8. Synthesis of high specific activity (1- sup 3 H) farnesyl pyrophosphate

    SciTech Connect

    Saljoughian, M.; Morimoto, H.; Williams, P.G.

    1991-08-01

    The synthesis of tritiated farnesyl pyrophosphate with high specific activity is reported. trans-trans Farnesol was oxidized to the corresponding aldehyde followed by reduction with lithium aluminium tritide (5%-{sup 3}H) to give trans-trans (1-{sup 3}H)farnesol. The specific radioactivity of the alcohol was determined from its triphenylsilane derivative, prepared under very mild conditions. The tritiated alcohol was phosphorylated by initial conversion to an allylic halide, and subsequent treatment of the halide with tris-tetra-n-butylammonium hydrogen pyrophosphate. The hydride procedure followed in this work has advantages over existing methods for the synthesis of tritiated farnesyl pyrophosphate, with the possibility of higher specific activity and a much higher yield obtained. 10 refs., 3 figs.

  9. A versatile photoactivatable probe designed to label the diphosphate binding site of farnesyl diphosphate utilizing enzymes.

    PubMed

    Henry, Olivier; Lopez-Gallego, Fernando; Agger, Sean A; Schmidt-Dannert, Claudia; Sen, Stephanie; Shintani, David; Cornish, Katrina; Distefano, Mark D

    2009-07-01

    Farnesyl diphosphate (FPP) is a substrate for a diverse number of enzymes found in nature. Photoactive analogues of isoprenoid diphosphates containing either benzophenone, diazotrifluoropropionate or azide groups have been useful for studying both the enzymes that synthesize FPP as well as those that employ FPP as a substrate. Here we describe the synthesis and properties of a new class of FPP analogues that links an unmodified farnesyl group to a diphosphate mimic containing a photoactive benzophenone moiety; thus, importantly, these compounds are photoactive FPP analogues that contain no modifications of the isoprenoid portion of the molecule that may interfere with substrate binding in the active site of an FPP utilizing enzyme. Two isomeric compounds containing meta- and para-substituted benzophenones were prepared. These two analogues inhibit Saccharomyces cerevisiae protein farnesyltransferase (ScPFTase) with IC(50) values of 5.8 (meta isomer) and 3.0 microM (para isomer); the more potent analogue, the para isomer, was shown to be a competitive inhibitor of ScPFTase with respect to FPP with a K(I) of 0.46 microM. Radiolabeled forms of both analogues selectively labeled the beta-subunit of ScPFTase. The para isomer was also shown to label Escherichia coli farnesyl diphosphate synthase and Drosophila melanogaster farnesyl diphosphate synthase. Finally, the para isomer was shown to be an alternative substrate for a sesquiterpene synthase from Nostoc sp. strain PCC7120, a cyanobacterial source; the compound also labeled the purified enzyme upon photolysis. Taken together, these results using a number of enzymes demonstrate that this new class of probes should be useful for a plethora of studies of FPP-utilizing enzymes.

  10. Farnesyl Diphosphate Synthase Localizes to the Cytoplasm of Trypanosoma cruzi and T.brucei

    PubMed Central

    Ferella, Marcela; Li, Zhu-Hong; Andersson, Björn; Docampo, Roberto

    2008-01-01

    The farnesyl diphosphate synthase (FPPS) has previously been characterized in trypanosomes as an essential enzyme for their survival and as the target for bisphosphonates, drugs that are effective both in vitro and in vivo against these parasites. Enzymes from the isoprenoid pathway have been assigned to different compartments in eukaryotes, including trypanosomatids. We here report that FPPS localizes to the cytoplasm of both Trypanosoma cruzi and T. brucei, and is not present in other organelles such as the mitochondria and glycosomes. PMID:18406406

  11. A Versatile Photoactivatable Probe Designed to Label the Diphosphate Binding Site of Farnesyl Diphosphate Utilizing Enzymes

    PubMed Central

    Henry, Olivier; Lopez-Gallego, Fernando; Agger, Sean A.; Schmidt-Dannert, Claudia; Sen, Stephanie; Shintani, David; Cornish, Katrina; Distefano, Mark D.

    2009-01-01

    Farnesyl diphosphate (FPP) is a substrate for a diverse number of enzymes found in nature. Photoactive analogues of isoprenoid diphosphates containing either benzophenone, diazotrifluropropionate or azide groups have been useful for studying both the enzymes that synthesize FPP as well as those that employ FPP as a substrate. Here we describe the synthesis and properties of a new class of FPP analogues that links an unmodified farnesyl group to a diphosphate mimic containing a photoactive benzophenone moiety; thus, importantly, these compounds are photoactive FPP analogues that contain no modifications of the isoprenoid portion of the molecule that may interfere with substrate binding in the active site of an FPP utilizing enzyme. Two isomeric compounds containing meta- and para-substituted benzophenones were prepared. These two analogues inhibit S. cerevisiae protein farnesyltransferase (ScPFTase) with IC50 values of 5.8 (meta isomer) and 3.0 µM (para isomer); the more potent analogue, the para isomer, was shown to be a competitive inhibitor of ScPFTase with respect to FPP with a KI of 0.46 µM. Radiolabeled forms of both analogues selectively labelled the β-subunit of ScPFTase. The para isomer was also shown to label E. coli farnesyl diphosphate synthase and Drosophila melanogaster farnesyl diphosphate synthase. Finally, the para isomer was shown to be an alternative substrate for a sesquiterpene synthase from Nostoc sp. strain PCC7120, a cyanobacterial source; the compound also labeled the purified enzyme upon photolysis. Taken together, these results using a number of enzymes demonstrate that this new class of probes should be useful for a plethora of studies of FPP-utilizing enzymes. PMID:19447628

  12. Farnesyl pyrophosphate inhibits epithelialization and wound healing through the glucocorticoid receptor.

    PubMed

    Vukelic, Sasa; Stojadinovic, Olivera; Pastar, Irena; Vouthounis, Constantinos; Krzyzanowska, Agata; Das, Sharmistha; Samuels, Herbert H; Tomic-Canic, Marjana

    2010-01-15

    Farnesyl pyrophosphate (FPP), a key intermediate in the mevalonate pathway and protein farnesylation, can act as an agonist for several nuclear hormone receptors. Here we show a novel mechanism by which FPP inhibits wound healing acting as an agonist for glucocorticoid receptor (GR). Elevation of endogenous FPP by the squalene synthetase inhibitor zaragozic acid A (ZGA) or addition of FPP to the cell culture medium results in activation and nuclear translocation of the GR, a known wound healing inhibitor. We used functional studies to evaluate the effects of FPP on wound healing. Both FPP and ZGA inhibited keratinocyte migration and epithelialization in vitro and ex vivo. These effects were independent of farnesylation and indicate that modulation of FPP levels in skin may be beneficial for wound healing. FPP inhibition of keratinocyte migration and wound healing proceeds, in part, by repression of the keratin 6 gene. Furthermore, we show that the 3-hydroxy-3-methylglutaryl-CoA-reductase inhibitor mevastatin, which blocks FPP formation, not only promotes epithelialization in acute wounds but also reverses the effect of ZGA on activation of the GR and inhibition of epithelialization. We conclude that FPP inhibits wound healing by acting as a GR agonist. Of special interest is that FPP is naturally present in cells prior to glucocorticoid synthesis and that FPP levels can be further altered by the statins. Therefore, our findings may provide a better understanding of the pleiotropic effects of statins as well as molecular mechanisms by which they may accelerate wound healing.

  13. Inhibition of farnesyl pyrophosphate synthase improves pressure overload induced chronic cardiac remodeling

    PubMed Central

    Zhao, Chen-Ze; Zhao, Xu-Ming; Yang, Jian; Mou, Yun; Chen, Bin; Wu, Huan-Dong; Dai, Dong-Pu; Ding, Jie; Hu, Shen-Jiang

    2016-01-01

    Farnesyl pyrophosphate synthase (FPPS) is a key enzyme in the mevalonate pathway. In our previous studies, we find that inhibition of FPPS attenuates angiotensin II-induced cardiac hypertrophy and fibrosis by suppressing RhoA while FPPS and Ras are up-regulated in pressure overload rats. In this study, we evaluate the effects and mechanisms of FPPS inhibition in pressure overload mice. Male FPPS-small interfering RNA (SiRNA) transgenic (Tg) mice and non-transgenic littermate control (NLC) were randomly divided into suprarenal abdominal aortic constriction (AAC) group and sham operation group. 12 weeks following AAC, mice were sacrificed by cervical dislocation. Histological and echocardiographic assessments showed that inhibition of FPPS improved chronic cardiac remodeling which was induced by AAC. The reductions of Ras farnesylation and GTP-Ras, as well as their downstream extracellular signal-related kinases 1/2 (ERK1/2) expression were observed in the heart of Tg-AAC mice compared with NLC-AAC mice, along with the reduction of fetal gene expression. We provide here important experimental evidence that inhibition of FPPS improves AAC induced chronic cardiac remodeling and fibrosis by the reduction of farnesylated Ras and the downregulation of Ras-ERK1/2 pathway. PMID:28008986

  14. Cloning and functional analysis of a cDNA encoding Ginkgo biloba farnesyl diphosphate synthase.

    PubMed

    Wang, Peng; Liao, Zhihua; Guo, Liang; Li, Wenchao; Chen, Min; Pi, Yan; Gong, Yifu; Sun, Xiaofen; Tang, Kexuan

    2004-10-31

    Farnesyl diphosphate synthase (FPS; EC2.5.1.1/EC2. 5.1.10) catalyzes the synthesis of farnesyl diphosphate, and provides precursor for biosynthesis of sesquiterpene and isoprenoids containing more than 15 isoprene units in Ginkgo biloba. Here we report the cloning, characterization and functional analysis of a new cDNA encoding FPS from G. biloba. The full-length cDNA (designated GbFPS) had 1731 bp with an open reading frame of 1170 bp encoding a polypeptide of 390 amino acids. The deduced GbFPS was similar to other known FPSs and contained all the conserved regions of trans-prenyl chain-elongating enzymes. Structural modeling showed that GbFPS had the typical structure of FPS, the most prominent feature of which is the arrangement of 13 core helices around a large central cavity. Southern blot analysis revealed a small FPS gene family in G. biloba. Expression analysis indicated that GbFPS expression was high in roots and leaves, and low in stems. Functional complementation of GbFPS in an FPS-deficient strain confirmed that GbFPS mediates farnesyl diphosphate biosynthesis.

  15. Synthesis and antibacterial evaluation of 3-Farnesyl-2-hydroxybenzoic acid from Piper multiplinervium.

    PubMed

    Malami, Ibrahim; Gibbons, Simon; Malkinson, John P

    2014-03-01

    3-Farnesyl-2-hydroxybenzoic acid is an antibacterial agent isolated from the leaves of Piper multiplinervium. This compound has activity against both Gram positive and Gram negative bacteria including Escherichia coli, Staphylococcus aureus and Helicobacter pylori. This research aimed to synthesize a natural antibacterial compound and its analogs. The synthesis of 3-Farnesyl-2-hydroxybenzoic acid consists of three steps: straightforward synthesis involving protection of phenolic hydroxyl group, coupling of suitable isoprenyl chain to the protected aromatic ring at ortho position followed by carboxylation with concomitant deprotection to give the derivatives of the salicylic acid. All the three prenylated compounds synthesized were found to exhibit spectrum of activity against S. aureus (ATCC) having MIC: 5.84×10(-3), 41.46×10(-2) and 6.19×10(-1) μmol/ml respectively. The compounds also displayed activity against resistance strain of S. aureus (SA1119B) having MIC: 5.84×10(-3), 7.29×10(-3) and 3.09×10(-1) μmol/ml respectively. This synthesis has been achieved and accomplished with the confirmation of it structure to that of the original natural product, thus producing the first synthesis of the natural product and providing the first synthesis of its analogs with 3-Farnesyl-2-hydroxybenzoic acid having biological activity higher than that of the original natural product. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Permanent farnesylation of lamin A mutants linked to progeria impairs its phosphorylation at serine 22 during interphase.

    PubMed

    Moiseeva, Olga; Lopes-Paciencia, Stéphane; Huot, Geneviève; Lessard, Frédéric; Ferbeyre, Gerardo

    2016-02-01

    Mutants of lamin A cause diseases including the Hutchinson-Gilford progeria syndrome (HGPS) characterized by premature aging. Lamin A undergoes a series of processing reactions, including farnesylation and proteolytic cleavage of the farnesylated C-terminal domain. The role of cleavage is unknown but mutations that affect this reaction lead to progeria. Here we show that interphase serine 22 phosphorylation of endogenous mutant lamin A (progerin) is defective in cells from HGPS patients. This defect can be mimicked by expressing progerin in human cells and prevented by inhibition of farnesylation. Furthermore, serine 22 phosphorylation of non-farnesylated progerin was enhanced by a mutation that disrupts lamin A head to tail interactions. The phosphorylation of lamin A or non-farnesylated progerin was associated to the formation of spherical intranuclear lamin A droplets that accumulate protein kinases of the CDK family capable of phosphorylating lamin A at serine 22. CDK inhibitors compromised the turnover of progerin, accelerated senescence of HGPS cells and reversed the effects of FTI on progerin levels. We discuss a model of progeria where faulty serine 22 phosphorylation compromises phase separation of lamin A polymers, leading to accumulation of functionally impaired lamin A structures.

  17. Permanent farnesylation of lamin A mutants linked to progeria impairs its phosphorylation at serine 22 during interphase

    PubMed Central

    Moiseeva, Olga; Lopes-Paciencia, Stéphane; Huot, Geneviève; Lessard, Frédéric; Ferbeyre, Gerardo

    2016-01-01

    Mutants of lamin A cause diseases including the Hutchinson-Gilford progeria syndrome (HGPS) characterized by premature aging. Lamin A undergoes a series of processing reactions, including farnesylation and proteolytic cleavage of the farnesylated C-terminal domain. The role of cleavage is unknown but mutations that affect this reaction lead to progeria. Here we show that interphase serine 22 phosphorylation of endogenous mutant lamin A (progerin) is defective in cells from HGPS patients. This defect can be mimicked by expressing progerin in human cells and prevented by inhibition of farnesylation. Furthermore, serine 22 phosphorylation of non-farnesylated progerin was enhanced by a mutation that disrupts lamin A head to tail interactions. The phosphorylation of lamin A or non-farnesylated progerin was associated to the formation of spherical intranuclear lamin A droplets that accumulate protein kinases of the CDK family capable of phosphorylating lamin A at serine 22. CDK inhibitors compromised the turnover of progerin, accelerated senescence of HGPS cells and reversed the effects of FTI on progerin levels. We discuss a model of progeria where faulty serine 22 phosphorylation compromises phase separation of lamin A polymers, leading to accumulation of functionally impaired lamin A structures. PMID:26922519

  18. AIPL1, a protein implicated in Leber's congenital amaurosis, interacts with and aids in processing of farnesylated proteins.

    PubMed

    Ramamurthy, Visvanathan; Roberts, Melanie; van den Akker, Focco; Niemi, Gregory; Reh, T A; Hurley, James B

    2003-10-28

    The most common form of blindness at birth, Leber's congenital amaurosis (LCA), is inherited in an autosomal recessive fashion. Mutations in six different retina-specific genes, including a recently discovered gene, AIPL1, have been linked to LCA in humans. To understand the molecular basis of LCA caused by aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) mutations, and to elucidate the normal function of AIPL1, we performed a yeast two-hybrid screen using AIPL1 as bait. The screen demonstrated that AIPL1 interacts specifically with farnesylated proteins. Mutations in AIPL1 linked to LCA compromise this activity. These findings suggest that the essential function of AIPL1 within photoreceptors requires interactions with farnesylated proteins. Analysis of isoprenylation in cultured human cells shows that AIPL1 enhances the processing of farnesylated proteins. Based on these findings, we propose that AIPL1 interacts with farnesylated proteins and plays an essential role in processing of farnesylated proteins in retina.

  19. Hibiscus cannabinus feruloyl-coa:monolignol transferase

    SciTech Connect

    Wilkerson, Curtis; Ralph, John; Withers, Saunia; Mansfield, Shawn D.

    2016-11-15

    The invention relates to isolated nucleic acids encoding a feruloyl-CoA:monolignol transferase and feruloyl-CoA:monolignol transferase enzymes. The isolated nucleic acids and/or the enzymes enable incorporation of monolignol ferulates into the lignin of plants, where such monolignol ferulates include, for example, p-coumaryl ferulate, coniferyl ferulate, and/or sinapyl ferulate. The invention also includes methods and plants that include nucleic acids encoding a feruloyl-CoA:monolignol transferase enzyme and/or feruloyl-CoA:monolignol transferase enzymes.

  20. Cyclization of farnesyl pyrophosphate to the sesquiterpene olefins humulene and caryophyllene by an enzyme system from sage (Salvia officinalis)

    SciTech Connect

    Croteau, R.; Gundy, A.

    1984-09-01

    A soluble enzyme preparation obtained from sage (Salvia officinalis) leaves was shown to catalyze the divalent metal-ion dependent cyclization of trans, trans-farnesyl pyrophosphate to the macrocyclic sesquiterpene olefins humulene and caryophyllene. The identities of the biosynthetic products were confirmed by radiochromatographic analysis and by preparation of crystalline derivatives, and the specificity of labeling in the cyclization reaction was established by chemical degradation of the olefins derived enzymatically from (1-3H2)farnesyl pyrophosphate. These results constitute the first report on the cyclization of farnesyl pyrophosphate to humulene and caryophyllene, two of the most common sesquiterpenes in nature, and the first description of a soluble sesquiterpene cyclase to be isolated from leaves of a higher plant.

  1. Cloning and characterization of bifunctional enzyme farnesyl diphosphate/geranylgeranyl diphosphate synthase from Plasmodium falciparum

    PubMed Central

    2013-01-01

    Background Isoprenoids are the most diverse and abundant group of natural products. In Plasmodium falciparum, isoprenoid synthesis proceeds through the methyl erythritol diphosphate pathway and the products are further metabolized by farnesyl diphosphate synthase (FPPS), turning this enzyme into a key branch point of the isoprenoid synthesis. Changes in FPPS activity could alter the flux of isoprenoid compounds downstream of FPPS and, hence, play a central role in the regulation of a number of essential functions in Plasmodium parasites. Methods The isolation and cloning of gene PF3D7_18400 was done by amplification from cDNA from mixed stage parasites of P. falciparum. After sequencing, the fragment was subcloned in pGEX2T for recombinant protein expression. To verify if the PF3D7_1128400 gene encodes a functional rPfFPPS protein, its catalytic activity was assessed using the substrate [4-14C] isopentenyl diphosphate and three different allylic substrates: dimethylallyl diphosphate, geranyl diphosphate or farnesyl diphosphate. The reaction products were identified by thin layer chromatography and reverse phase high-performance liquid chromatography. To confirm the product spectrum formed of rPfFPPS, isoprenic compounds were also identified by mass spectrometry. Apparent kinetic constants KM and Vmax for each substrate were determined by Michaelis–Menten; also, inhibition assays were performed using risedronate. Results The expressed protein of P. falciparum FPPS (rPfFPPS) catalyzes the synthesis of farnesyl diphosphate, as well as geranylgeranyl diphosphate, being therefore a bifunctional FPPS/geranylgeranyl diphosphate synthase (GGPPS) enzyme. The apparent KM values for the substrates dimethylallyl diphosphate, geranyl diphosphate and farnesyl diphosphate were, respectively, 68 ± 5 μM, 7.8 ± 1.3 μM and 2.06 ± 0.4 μM. The protein is expressed constitutively in all intra-erythrocytic stages of P. falciparum, demonstrated by using transgenic

  2. Feruloyl-CoA:monolignol transferase

    DOEpatents

    Wilkerson, Curtis; Ralph, John; Withers, Saunia; Mansfield, Shawn D.

    2016-11-08

    The invention relates to nucleic acids encoding a feruloyl-CoA:monolignol transferase and the feruloyl-CoA:monolignol transferase enzyme that enables incorporation of monolignol ferulates, for example, including p-coumaryl ferulate, coniferyl ferulate, and sinapyl ferulate, into the lignin of plants.

  3. Feruloyl-CoA:monolignol transferase

    DOEpatents

    Wilkerson, Curtis; Ralph, John; Withers, Saunia; Mansfield, Shawn D.

    2016-09-13

    The invention relates to nucleic acids encoding a feruloyl-CoA:monolignol transferase and the feruloyl-CoA:monolignol transferase enzyme that enables incorporation of monolignol ferulates, for example, including p-coumaryl ferulate, coniferyl ferulate, and sinapyl ferulate, into the lignin of plants.

  4. VPS35 binds farnesylated N-Ras in the cytosol to regulate N-Ras trafficking.

    PubMed

    Zhou, Mo; Wiener, Heidi; Su, Wenjuan; Zhou, Yong; Liot, Caroline; Ahearn, Ian; Hancock, John F; Philips, Mark R

    2016-08-15

    Ras guanosine triphosphatases (GTPases) regulate signaling pathways only when associated with cellular membranes through their C-terminal prenylated regions. Ras proteins move between membrane compartments in part via diffusion-limited, fluid phase transfer through the cytosol, suggesting that chaperones sequester the polyisoprene lipid from the aqueous environment. In this study, we analyze the nature of the pool of endogenous Ras proteins found in the cytosol. The majority of the pool consists of farnesylated, but not palmitoylated, N-Ras that is associated with a high molecular weight (HMW) complex. Affinity purification and mass spectrographic identification revealed that among the proteins found in the HMW fraction is VPS35, a latent cytosolic component of the retromer coat. VPS35 bound to N-Ras in a farnesyl-dependent, but neither palmitoyl- nor guanosine triphosphate (GTP)-dependent, fashion. Silencing VPS35 increased N-Ras's association with cytoplasmic vesicles, diminished GTP loading of Ras, and inhibited mitogen-activated protein kinase signaling and growth of N-Ras-dependent melanoma cells.

  5. Nuclear receptor engineering based on novel structure activity relationships revealed by farnesyl pyrophosphate

    PubMed Central

    Goyanka, Ritu; Das, Sharmistha; Samuels, Herbert H.; Cardozo, Timothy

    2010-01-01

    Nuclear receptors (NRs) comprise the second largest protein family targeted by currently available drugs, acting via specific ligand interactions within the ligand binding domain (LBD). Recently, farnesyl pyrophosphate (FPP) was shown to be a unique promiscuous NR ligand, activating a subset of NR family members and inhibiting wound healing in skin. The current study aimed at visualizing the unique basis of FPP interaction with multiple receptors in order to identify general structure–activity relationships that operate across the NR family. Docking of FPP to the 3D structures of the LBDs of a diverse set of NRs consistently revealed an electrostatic FPP pyrophosphate contact with an NR arginine conserved in the NR family, a hydrophobic farnesyl contact with NR helix-12 and a ligand binding pocket volume between 300 and 430 Å3 as the minimal requirements for FPP activation of any NR. Lack of any of these structural features appears to render a given NR resistant to FPP activation. We used these structure–activity relationships to rationally design and successfully engineer several mutant human estrogen receptors that retain responsiveness to estradiol but no longer respond to FPP. PMID:20817759

  6. Nuclear receptor engineering based on novel structure activity relationships revealed by farnesyl pyrophosphate.

    PubMed

    Goyanka, Ritu; Das, Sharmistha; Samuels, Herbert H; Cardozo, Timothy

    2010-11-01

    Nuclear receptors (NRs) comprise the second largest protein family targeted by currently available drugs, acting via specific ligand interactions within the ligand binding domain (LBD). Recently, farnesyl pyrophosphate (FPP) was shown to be a unique promiscuous NR ligand, activating a subset of NR family members and inhibiting wound healing in skin. The current study aimed at visualizing the unique basis of FPP interaction with multiple receptors in order to identify general structure-activity relationships that operate across the NR family. Docking of FPP to the 3D structures of the LBDs of a diverse set of NRs consistently revealed an electrostatic FPP pyrophosphate contact with an NR arginine conserved in the NR family, a hydrophobic farnesyl contact with NR helix-12 and a ligand binding pocket volume between 300 and 430 Å(3) as the minimal requirements for FPP activation of any NR. Lack of any of these structural features appears to render a given NR resistant to FPP activation. We used these structure-activity relationships to rationally design and successfully engineer several mutant human estrogen receptors that retain responsiveness to estradiol but no longer respond to FPP.

  7. Cloning of the Arabidopsis WIGGUM gene identifies a role for farnesylation in meristem development

    PubMed Central

    Ziegelhoffer, Eva C.; Medrano, Leonard J.; Meyerowitz, Elliot M.

    2000-01-01

    Control of cellular proliferation in plant meristems is important for maintaining the correct number and position of developing organs. One of the genes identified in the control of floral and apical meristem size and floral organ number in Arabidopsis thaliana is WIGGUM. In wiggum mutants, one of the most striking phenotypes is an increase in floral organ number, particularly in the sepals and petals, correlating with an increase in the width of young floral meristems. Additional phenotypes include reduced and delayed germination, delayed flowering, maturation, and senescence, decreased internode elongation, shortened roots, aberrant phyllotaxy of flowers, aberrant sepal development, floral buds that open precociously, and occasional apical meristem fasciation. As a first step in determining a molecular function for WIGGUM, we used positional cloning to identify the gene. DNA sequencing revealed that WIGGUM is identical to ERA1 (enhanced response to abscisic acid), a previously identified farnesyltransferase β-subunit gene of Arabidopsis. This finding provides a link between protein modification by farnesylation and the control of meristem size. Using in situ hybridization, we examined the expression of ERA1 throughout development and found it to be nearly ubiquitous. This extensive expression domain is consistent with the pleiotropic nature of wiggum mutants and highlights a broad utility for farnesylation in plant growth and development. PMID:10840062

  8. A corpora allata farnesyl diphosphate synthase in mosquitoes displaying a metal ion dependent substrate specificity

    PubMed Central

    Rivera-Perez, Crisalejandra; Nyati, Pratik; Noriega, Fernando G.

    2015-01-01

    Farnesyl diphosphate synthase (FPPS) is a key enzyme in isoprenoid biosynthesis, it catalyzes the head-to-tail condensation of dimethylallyl diphosphate (DMAPP) with two molecules of isopentenyl diphosphate (IPP) to generate farnesyl diphosphate (FPP), a precursor of juvenile hormone (JH). In this study, we functionally characterized an Aedes aegypti FPPS (AaFPPS) expressed in the corpora allata. AaFPPS is the only FPPS gene present in the genome of the yellow fever mosquito, it encodes a 49.6 kDa protein exhibiting all the characteristic conserved sequence domains on prenyltransferases. AaFPPS displays its activity in the presence of metal cofactors; and the product condensation is dependent of the divalent cation. Mg2+ ions lead to the production of FPP, while the presence of Co2+ ions lead to geranyl diphosphate (GPP) production. In the presence of Mg2+ the AaFPPS affinity for allylic substrates is GPP>DMAPP>IPP. These results suggest that AaFPPS displays “catalytic promiscuity”, changing the type and ratio of products released (GPP or FPP) depending on allylic substrate concentrations and the presence of different metal cofactors. This metal ion-dependent regulatory mechanism allows a single enzyme to selectively control the metabolites it produces, thus potentially altering the flow of carbon into separate metabolic pathways. PMID:26188328

  9. A corpora allata farnesyl diphosphate synthase in mosquitoes displaying a metal ion dependent substrate specificity.

    PubMed

    Rivera-Perez, Crisalejandra; Nyati, Pratik; Noriega, Fernando G

    2015-09-01

    Farnesyl diphosphate synthase (FPPS) is a key enzyme in isoprenoid biosynthesis, it catalyzes the head-to-tail condensation of dimethylallyl diphosphate (DMAPP) with two molecules of isopentenyl diphosphate (IPP) to generate farnesyl diphosphate (FPP), a precursor of juvenile hormone (JH). In this study, we functionally characterized an Aedes aegypti FPPS (AaFPPS) expressed in the corpora allata. AaFPPS is the only FPPS gene present in the genome of the yellow fever mosquito, it encodes a 49.6 kDa protein exhibiting all the characteristic conserved sequence domains on prenyltransferases. AaFPPS displays its activity in the presence of metal cofactors; and the product condensation is dependent of the divalent cation. Mg(2+) ions lead to the production of FPP, while the presence of Co(2+) ions lead to geranyl diphosphate (GPP) production. In the presence of Mg(2+) the AaFPPS affinity for allylic substrates is GPP > DMAPP > IPP. These results suggest that AaFPPS displays "catalytic promiscuity", changing the type and ratio of products released (GPP or FPP) depending on allylic substrate concentrations and the presence of different metal cofactors. This metal ion-dependent regulatory mechanism allows a single enzyme to selectively control the metabolites it produces, thus potentially altering the flow of carbon into separate metabolic pathways.

  10. Cloning and Characterization of Farnesyl Diphosphate Synthase Gene Involved in Triterpenoids Biosynthesis from Poria cocos

    PubMed Central

    Wang, Jianrong; Li, Yangyuan; Liu, Danni

    2014-01-01

    Poria cocos (P. cocos) has long been used as traditional Chinese medicine and triterpenoids are the most important pharmacologically active constituents of this fungus. Farnesyl pyrophosphate synthase (FPS) is a key enzyme of triterpenoids biosynthesis. The gene encoding FPS was cloned from P. cocos by degenerate PCR, inverse PCR and cassette PCR. The open reading frame of the gene is 1086 bp in length, corresponding to a predicted polypeptide of 361 amino acid residues with a molecular weight of 41.2 kDa. Comparison of the P. cocos FPS deduced amino acid sequence with other species showed the highest identity with Ganoderma lucidum (74%). The predicted P. cocos FPS shares at least four conserved regions involved in the enzymatic activity with the FPSs of varied species. The recombinant protein was expressed in Pichia pastoris and purified. Gas chromatography analysis showed that the recombinant FPS could catalyze the formation of farnesyl diphosphate (FPP) from geranyl diphosphate (GPP) and isopentenyl diphosphate (IPP). Furthermore, the expression profile of the FPS gene and content of total triterpenoids under different stages of development and methyl jasmonate treatments were determined. The results indicated that there is a positive correlation between the activity of FPS and the amount of total triterpenoids produced in P. cocos. PMID:25474088

  11. Farnesylation of Ydj1 is required for in vivo interaction with Hsp90 client proteins.

    PubMed

    Flom, Gary A; Lemieszek, Marta; Fortunato, Elizabeth A; Johnson, Jill L

    2008-12-01

    Ydj1 of Saccharomyces cerevisiae is an abundant cytosolic Hsp40, or J-type, molecular chaperone. Ydj1 cooperates with Hsp70 of the Ssa family in the translocation of preproteins to the ER and mitochondria and in the maturation of Hsp90 client proteins. The substrate-binding domain of Ydj1 directly interacts with steroid receptors and is required for the activity of diverse Hsp90-dependent client proteins. However, the effect of Ydj1 alteration on client interaction was unknown. We analyzed the in vivo interaction of Ydj1 with the protein kinase Ste11 and the glucocorticoid receptor. Amino acid alterations in the proposed client-binding domain or zinc-binding domain had minor effects on the physical interaction of Ydj1 with both clients. However, alteration of the carboxy-terminal farnesylation signal disrupted the functional and physical interaction of Ydj1 and Hsp90 with both clients. Similar effects were observed upon deletion of RAM1, which encodes one of the subunits of yeast farnesyltransferase. Our results indicate that farnesylation is a major factor contributing to the specific requirement for Ydj1 in promoting proper regulation and activation of diverse Hsp90 clients.

  12. VPS35 binds farnesylated N-Ras in the cytosol to regulate N-Ras trafficking

    PubMed Central

    Wiener, Heidi; Su, Wenjuan; Liot, Caroline; Hancock, John F.

    2016-01-01

    Ras guanosine triphosphatases (GTPases) regulate signaling pathways only when associated with cellular membranes through their C-terminal prenylated regions. Ras proteins move between membrane compartments in part via diffusion-limited, fluid phase transfer through the cytosol, suggesting that chaperones sequester the polyisoprene lipid from the aqueous environment. In this study, we analyze the nature of the pool of endogenous Ras proteins found in the cytosol. The majority of the pool consists of farnesylated, but not palmitoylated, N-Ras that is associated with a high molecular weight (HMW) complex. Affinity purification and mass spectrographic identification revealed that among the proteins found in the HMW fraction is VPS35, a latent cytosolic component of the retromer coat. VPS35 bound to N-Ras in a farnesyl-dependent, but neither palmitoyl- nor guanosine triphosphate (GTP)–dependent, fashion. Silencing VPS35 increased N-Ras’s association with cytoplasmic vesicles, diminished GTP loading of Ras, and inhibited mitogen-activated protein kinase signaling and growth of N-Ras–dependent melanoma cells. PMID:27502489

  13. Functional Characterization of the Xanthophyllomyces dendrorhous Farnesyl Pyrophosphate Synthase and Geranylgeranyl Pyrophosphate Synthase Encoding Genes That Are Involved in the Synthesis of Isoprenoid Precursors

    PubMed Central

    Niklitschek, Mauricio; Sepúlveda, Dionisia; Rojas, María Cecilia; Baeza, Marcelo; Cifuentes, Víctor

    2014-01-01

    The yeast Xanthophyllomyces dendrorhous synthesizes the carotenoid astaxanthin, which has applications in biotechnology because of its antioxidant and pigmentation properties. However, wild-type strains produce too low amounts of carotenoids to be industrially competitive. Considering this background, it is indispensable to understand how the synthesis of astaxanthin is controlled and regulated in this yeast. In this work, the steps leading to the synthesis of the carotenoid precursor geranylgeranyl pyrophosphate (GGPP, C20) in X. dendrorhous from isopentenyl pyrophosphate (IPP, C5) and dimethylallyl pyrophosphate (DMAPP, C5) was characterized. Two prenyl transferase encoding genes, FPS and crtE, were expressed in E. coli. The enzymatic assays using recombinant E. coli protein extracts demonstrated that FPS and crtE encode a farnesyl pyrophosphate (FPP, C15) synthase and a GGPP-synthase, respectively. X. dendrorhous FPP-synthase produces geranyl pyrophosphate (GPP, C10) from IPP and DMAPP and FPP from IPP and GPP, while the X. dendrorhous GGPP-synthase utilizes only FPP and IPP as substrates to produce GGPP. Additionally, the FPS and crtE genes were over-expressed in X. dendrorhous, resulting in an increase of the total carotenoid production. Because the parental strain is diploid, the deletion of one of the alleles of these genes did not affect the total carotenoid production, but the composition was significantly altered. These results suggest that the over-expression of these genes might provoke a higher carbon flux towards carotenogenesis, most likely involving an earlier formation of a carotenogenic enzyme complex. Conversely, the lower carbon flux towards carotenogenesis in the deletion mutants might delay or lead to a partial formation of a carotenogenic enzyme complex, which could explain the accumulation of astaxanthin carotenoid precursors in these mutants. In conclusion, the FPS and the crtE genes represent good candidates to manipulate to favor

  14. Blocking farnesylation of the prelamin A variant in Hutchinson-Gilford progeria syndrome alters the distribution of A-type lamins.

    PubMed

    Wang, Yuexia; Ostlund, Cecilia; Choi, Jason C; Swayne, Theresa C; Gundersen, Gregg G; Worman, Howard J

    2012-01-01

    Mutations in the lamin A/C gene that cause Hutchinson-Gilford progeria syndrome lead to expression of a truncated, permanently farnesylated prelamin A variant called progerin. Blocking farnesylation leads to an improvement in the abnormal nuclear morphology observed in cells expressing progerin, which is associated with a re-localization of the variant protein from the nuclear envelope to the nuclear interior. We now show that a progerin construct that cannot be farnesylated is localized primarily in intranuclear foci and that its diffusional mobility is significantly greater than that of farnesylated progerin localized predominantly at the nuclear envelope. Expression of non-farnesylated progerin in transfected cells leads to a redistribution of lamin A and lamin C away from the nuclear envelope into intranuclear foci but does not significantly affect the localization of endogenous lamin B1 at nuclear envelope. There is a similar redistribution of lamin A and lamin C into intranuclear foci in transfected cells expressing progerin in which protein farnesylation is blocked by treatment with a protein farnesyltransferase inhibitor. Blocking farnesylation of progerin can lead to a redistribution of normal A-type lamins away from the inner nuclear envelope. This may have implications for using drugs that block protein prenylation to treat children with Hutchinson-Gilford progeria syndrome. These findings also provide additional evidence that A-type and B-type lamins can form separate microdomains within the nucleus.

  15. Absence of progeria-like disease phenotypes in knock-in mice expressing a non-farnesylated version of progerin.

    PubMed

    Yang, Shao H; Chang, Sandy Y; Ren, Shuxun; Wang, Yibin; Andres, Douglas A; Spielmann, H Peter; Fong, Loren G; Young, Stephen G

    2011-02-01

    Hutchinson-Gilford progeria syndrome (HGPS) is caused by a mutant prelamin A, progerin, that terminates with a farnesylcysteine. HGPS knock-in mice (Lmna(HG/+)) develop severe progeria-like disease phenotypes. These phenotypes can be ameliorated with a protein farnesyltransferase inhibitor (FTI), suggesting that progerin's farnesyl lipid is important for disease pathogenesis and raising the possibility that FTIs could be useful for treating humans with HGPS. Subsequent studies showed that mice expressing non-farnesylated progerin (Lmna(nHG/+) mice, in which progerin's carboxyl-terminal -CSIM motif was changed to -SSIM) also develop severe progeria, raising doubts about whether any treatment targeting protein prenylation would be particularly effective. We suspected that those doubts might be premature and hypothesized that the persistent disease in Lmna(nHG/+) mice could be an unanticipated consequence of the cysteine-to-serine substitution that was used to eliminate farnesylation. To test this hypothesis, we generated a second knock-in allele yielding non-farnesylated progerin (Lmna(csmHG)) in which the carboxyl-terminal -CSIM motif was changed to -CSM. We then compared disease phenotypes in mice harboring the Lmna(nHG) or Lmna(csmHG) allele. As expected, Lmna(nHG/+) and Lmna(nHG/nHG) mice developed severe progeria-like disease phenotypes, including osteolytic lesions and rib fractures, osteoporosis, slow growth and reduced survival. In contrast, Lmna(csmHG/+) and Lmna(csmHG/csmHG) mice exhibited no bone disease and displayed entirely normal body weights and survival. The frequencies of misshapen cell nuclei were lower in Lmna(csmHG/+) and Lmna(csmHG/csmHG) fibroblasts. These studies show that the ability of non-farnesylated progerin to elicit disease depends on the carboxyl-terminal mutation used to eliminate protein prenylation.

  16. Nifedipine prevents etoposide-induced caspase-3 activation, prenyl transferase degradation and loss in cell viability in pancreatic β-cells

    PubMed Central

    Arora, Daleep K.; Mohammed, Abiy M.; Kowluru, Anjaneyulu

    2012-01-01

    Emerging evidence implicates novel roles for post-translational prenylation [i.e., farnesylation and geranylgeranylation] of various signaling proteins in a variety of cellular functions including hormone secretion, survival and apoptosis. In the context of cellular apoptosis, it has been shown previously that caspase-3 activation, a hallmark of mitochondrial dysregulation, promotes hydrolysis of several key cellular proteins. We report herein that exposure of insulin-secreting INS 832/13 cells or normal rat islets to etoposide leads to significant activation of caspase-3 and subsequent degradation of the common α-subunit of farnesyl/geranylgeranyl transferases [FTase/GGTase]. Furthermore, the above stated signaling steps were prevented by Z-DEVD-FMK, a known inhibitor of caspase-3. In addition, treatment of cell lysates with recombinant caspase-3 also caused FTase/GGTase α-subunit degradation. Moreover, nifedipine, a calcium channel blocker, markedly attenuated etoposide-induced caspase-3 activation, FTase/GGTase α-subunit degradation in INS 832/13 cells and normal rat islets. Further, nifedipine significantly restored etoposide-induced loss in metabolic cell viability in INS 832/13 cells. Based on these findings, we conclude that etoposide induces loss in cell viability by inducing mitochondrial dysfunction, caspase-3 activation and degradation of FTase/GGTase α-subunit. Potential significance of these findings in the context of protein prenylation and β-cell survival are discussed. PMID:23054080

  17. Molecular Cloning and Characterisation of Farnesyl Pyrophosphate Synthase from Tripterygium wilfordii

    PubMed Central

    Zhao, Yu-Jun; Chen, Xin; Zhang, Meng; Su, Ping; Liu, Yu-Jia; Tong, Yu-Ru; Wang, Xiu-Juan; Huang, Lu-Qi; Gao, Wei

    2015-01-01

    Farnesylpyrophosphate synthase (FPS) catalyzes the biosynthesis of farnesyl pyrophosphate (FPP), which is an important precursor of sesquiterpenoids such as artemisinin and wilfordine. In the present study, we report the molecular cloning and characterization of two full-length cDNAs encoding FPSs from Tripterygium wilfordii (TwFPSs). TwFPSs maintained their capability to synthesise FPP in vitro when purified as recombinant proteins from E. coli. Consistent with the endogenous role of FPS in FPP biosynthesis, TwFPSs were highly expressed in T. wilfordii roots, and were up-regulated upon methyl jasmonate (MeJA) treatment. The global gene expression profiles suggested that the TwFPSs might play an important regulatory role interpenoid biosynthesis in T. wilfordii, laying the groundwork for the future study of the synthetic biology of natural terpene products. PMID:25938487

  18. Two pairs of farnesyl phenolic enantiomers as natural nitric oxide inhibitors from Ganoderma sinense.

    PubMed

    Wang, Meng; Wang, Fei; Xu, Feng; Ding, Li-Qin; Zhang, Qian; Li, Hui-Xiang; Zhao, Feng; Wang, Li-Qing; Zhu, Li-Han; Chen, Li-Xia; Qiu, Feng

    2016-07-15

    Four new farnesyl phenolic compounds, ganosinensols A-D (1-4) were isolated from the 95% EtOH extract of the fruiting bodies of Ganoderma sinense. Two pairs of enantiomers, 1/2, and 3/4 were isolated by HPLC using a Daicel Chiralpak IE column. Their structures were elucidated from extensive spectroscopic analyses and comparison with literature data. The absolute configurations of 1-4 were assigned by ECD spectra. All of these isolated compounds showed potent inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages, with IC50 values from 1.15 to 2.26μM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Fluorescent Farnesyl Diphosphate Analogue: A Probe To Validate trans-Prenyltransferase Inhibitors.

    PubMed

    Teng, Kuo-Hsun; Hsu, Erh-Ting; Chang, Ying-Hsuan; Lin, Sheng-Wei; Liang, Po-Huang

    2016-08-09

    Some trans-prenyltransferases, such as long-chain C40 octaprenyl diphosphate synthase (OPPS), short-chain C15 farnesyl diphosphate synthase (FPPS), and C20 geranylgeranyl diphosphate synthase (GGPPS), are important drug targets. These enzymes catalyze chain elongation of FPP or geranyl diphosphate (GPP) through condensation reactions with isopentenyl diphosphate (IPP), forming designated numbers of trans-double bonds in the final products. To facilitate drug discovery, we report here a sensitive and reliable fluorescence-based assay for monitoring their activities in real time. MANT-O-GPP, a fluorescent analogue of FPP, was used as an alternative substrate and converted by the wild-type OPPS and the engineered FPPS and GGPPS into sufficiently long products with enhanced fluorescence intensities. This fluorescence probe was used to reveal the inhibitory mechanism of zoledronate, a bisphosphonate drug that targets human FPPS and possibly GGPPS.

  20. Molecular Cloning and Characterisation of Farnesyl Pyrophosphate Synthase from Tripterygium wilfordii.

    PubMed

    Zhao, Yu-Jun; Chen, Xin; Zhang, Meng; Su, Ping; Liu, Yu-Jia; Tong, Yu-Ru; Wang, Xiu-Juan; Huang, Lu-Qi; Gao, Wei

    2015-01-01

    Farnesylpyrophosphate synthase (FPS) catalyzes the biosynthesis of farnesyl pyrophosphate (FPP), which is an important precursor of sesquiterpenoids such as artemisinin and wilfordine. In the present study, we report the molecular cloning and characterization of two full-length cDNAs encoding FPSs from Tripterygium wilfordii (TwFPSs). TwFPSs maintained their capability to synthesise FPP in vitro when purified as recombinant proteins from E. coli. Consistent with the endogenous role of FPS in FPP biosynthesis, TwFPSs were highly expressed in T. wilfordii roots, and were up-regulated upon methyl jasmonate (MeJA) treatment. The global gene expression profiles suggested that the TwFPSs might play an important regulatory role interpenoid biosynthesis in T. wilfordii, laying the groundwork for the future study of the synthetic biology of natural terpene products.

  1. Structure Conservation and Differential Expression of Farnesyl Diphosphate Synthase Genes in Euphorbiaceous Plants

    PubMed Central

    Guo, Dong; Li, Hui-Liang; Peng, Shi-Qing

    2015-01-01

    Farnesyl diphosphate synthase (FPS) is a key enzyme of isoprenoids biosynthesis. However, knowledge of the FPSs of euphorbiaceous species is limited. In this study, ten FPSs were identified in four euphorbiaceous plants. These FPSs exhibited similar exon/intron structure. The deduced FPS proteins showed close identities and exhibited the typical structure of plant FPS. The members of the FPS family exhibit tissue expression patterns that vary among several euphorbiaceous plant species under normal growth conditions. The expression profiles reveal spatial and temporal variations in the expression of FPSs of different tissues from Euphorbiaceous plants. Our results revealed wide conservation of FPSs and diverse expression in euphorbiaceous plants during growth and development. PMID:26389894

  2. Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate.

    PubMed

    Samoudi, Mojtaba; Omid Yeganeh, Negar; Shahbani Zahiri, Hossein; Shariati, Parvin; Hajhosseini, Reza

    2015-01-01

    Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli). Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transformed by the encoding gene for FPPS (ispA) under the control of either the trc or P BAD promoters. Over-expression of ispA under the control of P BAD promoter led to a relative increase in CoQ 10 production only in recombinant E. coli Br although induction by arabinose resulted in partial reduction of CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains. Over-expression of ispA under the control of stronger trc promoter, however, led to a severe decrease in CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains, as reflected by reductions from 629±40 to 30±13 and 564±28 to 80±14 μg/g Dried Cell Weight (DCW), respectively. The results showed high level of FPP reduces endogenous CoQ 8 production as well and that CoQs are produced in a complimentary manner, as the increase in production of one decreases the production of the other. The reduction in CoQ 10 production can be a result of Dds inhibition by high FPP concentration. Therefore, more effort is needed to verify the role of intermediate metabolite concentration and to optimize production of CoQ 10 .

  3. Impact of farnesylation inhibitors on survival in Hutchinson-Gilford progeria syndrome.

    PubMed

    Gordon, Leslie B; Massaro, Joe; D'Agostino, Ralph B; Campbell, Susan E; Brazier, Joan; Brown, W Ted; Kleinman, Monica E; Kieran, Mark W

    2014-07-01

    Hutchinson-Gilford progeria syndrome is an ultrarare segmental premature aging disease resulting in early death from heart attack or stroke. There is no approved treatment, but starting in 2007, several recent single-arm clinical trials administered inhibitors of protein farnesylation aimed at reducing toxicity of the disease-producing protein progerin. No study assessed whether treatments influence patient survival. The key elements necessary for this analysis are a robust natural history of survival and comparison with a sufficiently large patient population that has been treated for a sufficient time period with disease-targeting medications. We generated Kaplan-Meier survival analyses for the largest untreated Hutchinson-Gilford progeria syndrome cohort to date. Mean survival was 14.6 years. Comparing survival for treated versus age- and sex-matched untreated cohorts, hazard ratio was 0.13 (95% confidence interval, 0.04-0.37; P<0.001) with median follow-up of 5.3 years from time of treatment initiation. There were 21 of 43 deaths in untreated versus 5 of 43 deaths among treated subjects. Treatment increased mean survival by 1.6 years. This study provides a robust untreated disease survival profile that can be used for comparisons now and in the future to assess changes in survival with treatments for Hutchinson-Gilford progeria syndrome. The current comparisons estimating increased survival with protein farnesylation inhibitors provide the first evidence of treatments influencing survival for this fatal disease. http://www.clinicaltrials.gov. Unique Indentifiers: NCT00425607, NCT00879034, and NCT00916747. © 2014 American Heart Association, Inc.

  4. Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate

    PubMed Central

    Samoudi, Mojtaba; Omid Yeganeh, Negar; Shahbani Zahiri, Hossein; Shariati, Parvin; Hajhosseini, Reza

    2015-01-01

    Background: Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli). Methods: Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transformed by the encoding gene for FPPS (ispA) under the control of either the trc or P BAD promoters. Results: Over-expression of ispA under the control of P BAD promoter led to a relative increase in CoQ 10 production only in recombinant E. coli Br although induction by arabinose resulted in partial reduction of CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains. Over-expression of ispA under the control of stronger trc promoter, however, led to a severe decrease in CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains, as reflected by reductions from 629±40 to 30±13 and 564±28 to 80±14 μg/g Dried Cell Weight (DCW), respectively. The results showed high level of FPP reduces endogenous CoQ 8 production as well and that CoQs are produced in a complimentary manner, as the increase in production of one decreases the production of the other. Conclusion: The reduction in CoQ 10 production can be a result of Dds inhibition by high FPP concentration. Therefore, more effort is needed to verify the role of intermediate metabolite concentration and to optimize production of CoQ 10 . PMID:26306151

  5. Impact of Farnesylation Inhibitors on Survival in Hutchinson-Gilford Progeria Syndrome

    PubMed Central

    Gordon, Leslie B.; Massaro, Joe; D'Agostino, Ralph B.; Campbell, Susan E.; Brazier, Joan; Brown, W. Ted; Kleinman, Monica E; Kieran, Mark W.

    2014-01-01

    Background Hutchinson-Gilford progeria syndrome is an ultra-rare segmental premature aging disease resulting in early death from heart attack or stroke. There is no approved treatment, but starting in 2007, several recent single arm clinical trials have administered inhibitors of protein farnesylation aimed at reducing toxicity of the disease-producing protein progerin. No study has assessed whether treatments influence patient survival. The key elements necessary for this analysis are a robust natural history of survival and comparison with a sufficiently large patient population that has been treated for a sufficient time period with disease-targeting medications. Methods and Results We generated survival Kaplan-Meier survival analyses for the largest untreated Hutchinson-Gilford progeria syndrome cohort to date. Mean survival was 14.6 years. Comparing survival for treated versus age-and-gender-matched untreated cohorts, hazard ratio was 0.13 (95% CI 0.04-0.37; P<0.001) with median follow-up of 5.3 years from time of treatment initiation. There were 21/43 deaths in untreated versus 5/43 deaths among treated subjects. Treatment increased mean survival by 1.6 years. Conclusions This study provides a robust untreated disease survival profile, which can be utilized for comparisons now and in the future to assess changes in survival with treatments for HGPS. The current comparisons estimating increased survival with protein farnesylation inhibitors provide the first evidence of treatments influencing survival for this fatal disease. Clinical Trial Registration Information www.clinicaltrials.gov. Indentifiers: NCT00425607, NCT00879034 and NCT00916747. PMID:24795390

  6. Segregation of negatively charged phospholipids by the polycationic and farnesylated membrane anchor of Kras.

    PubMed

    Janosi, Lorant; Gorfe, Alemayehu A

    2010-12-01

    The Kras protein, a member of the Ras family of bio-switches that are frequently mutated in cancer and developmental disorders, becomes functional when anchored to the inner surface of the plasma membrane. It is well known that membrane attachment involves the farnesylated and poylcationic C-terminus of the protein. However, little is known about the structure of the complex and the specific protein-lipid interactions that are responsible for the binding. On the basis of data from extensive (>0.55 μs) molecular dynamics simulations of multiple Kras anchors in bilayers of POPC/POPG lipids (4:1 ratio), we show that, as expected, Kras is tethered to the bilayer surface by specific lysine-POPG salt bridges and by nonspecific farnesyl-phospholipid van der Waals interactions. Unexpectedly, however, only the C-terminal five of the eight Kras Lys side chains were found to directly interact with the bilayer, with the N-terminal ones staying in water. Furthermore, the positively charged Kras anchors pull the negatively charged POPG lipids together, leading to the clustering of the POPG lipids around the proteins. This selective Kras-POPG interaction is directly related to the specific geometry of the backbone, which exists in two major conformational states: 1), a stable native-like ensemble of structures characterized by an extended geometry with a pseudohelical turn; and 2), less stable nonnative ensembles of conformers characterized by severely bent geometries. Finally, although the interface-bound anchor has little effect on the overall structure of the bilayer, it induces local thinning within a persistence length of ∼12 Å. Our results thus go beyond documenting how Kras attaches to a mixed bilayer of charged and neutral lipids; they highlight a fascinating process of protein-induced lipid sorting coupled with the (re)shaping of a surface-bound protein by the host lipids. Copyright © 2010 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  7. Two Eucommia farnesyl diphosphate synthases exhibit distinct enzymatic properties leading to end product preferences.

    PubMed

    Kajiura, Hiroyuki; Suzuki, Nobuaki; Tokumoto, Yuji; Yoshizawa, Takuya; Takeno, Shinya; Fujiyama, Kazuhito; Kaneko, Yoshinobu; Matsumura, Hiroyoshi; Nakazawa, Yoshihisa

    2017-08-01

    Farnesyl diphosphate synthase (FPS) is an essential enzyme in the biosynthesis of prenyl precursors for the production of primary and secondary metabolites, including sterols, dolichols, carotenoids and ubiquinones, and for the modification of proteins. Here we identified and characterized two FPSs (EuFPS1 and EuFPS2) from the plant Eucommia ulmoides. The EuFPSs had seven highly conserved prenyltransferase-specific domains that are critical for activity. Complementation and biochemical analyses using bacterially produced recombinant EuFPS isoforms showed that the EuFPSs had FPP synthesis activities both in vivo and in vitro. In addition to the typical reaction mechanisms of FPS, EuFPSs utilized farnesyl diphosphate (FPP) as an allylic substrate and participated in further elongation of the isoprenyl chain, resulting in the synthesis of geranylgeranyl diphosphate. However, despite the high amino acid similarities between the two EuFPS isozymes, their specific activities, substrate preferences, and final reaction products were different. The use of dimethylallyl diphosphate (DMAPP) as an allylic substrate highlighted the differences between the two enzymes: depending on the pH, the metal ion cofactor, and the cofactor concentration, EuFPS2 accumulated geranyl diphosphate as an intermediate product at a constant rate, whereas EuFPS1 synthesized little geranyl diphosphate. The reaction kinetics of the EuFPSs demonstrated that isopentenyl diphosphate and DMAPP were used both as substrates and as inhibitors of EuFPS activity. Taken together, the results indicate that the biosynthesis of FPP is highly regulated by various factors indispensable for EuFPS reactions in plants. Copyright © 2017. Published by Elsevier B.V.

  8. Roles for glutathione transferases in antioxidant recycling

    PubMed Central

    Dixon, David P; Steel, Patrick G

    2011-01-01

    Uniquely among the plant glutathione transferases, two classes possess a catalytic cysteine capable of performing glutathione-dependent reductions. These are the dehydroascorbate reductases (DHARs) and the lambda-class glutathione transferases (GSTLs). Using immobilized GSTLs probed with crude plant extracts we have identified flavonols as high affinity ligands and subsequently demonstrated a novel glutathione-dependent role for these enzymes in recycling oxidized quercetin. By comparing the activities of DHARs and GSTLs we now propose a unified catalytic mechanism that suggests oxidized anthocyanidins and tocopherols may be alternative polyphenolic substrates of GSTLs. PMID:21778824

  9. Determination of isopentenyl diphosphate and farnesyl diphosphate in tissue samples with a comment on secondary regulation of polyisoprenoid biosynthesis

    SciTech Connect

    Bruenger, E.; Rilling, H.C.

    1988-09-01

    A double-isotope dilution procedure is described for the determination of two isoprenoid precursors, isopentenyl and farnesyl diphosphate. Recovery of each is determined by the addition of the appropriate radioactive diphosphate to the tissue sample. After partial purification, each is coupled by a prenyltransferase with a cosubstrate of known specific activity. The products, doubly labeled farnesyl and geranylgeranyl diphosphates, are cleaved to the parent alcohols by alkaline phosphatase. The resulting polyprenols are isolated by reversed-phase thin-layer chromatography and their radioisotopic content is determined. The levels of these precursors have been measured in livers of rats and mice that have been maintained on several different diets. The concentration of each was about 0.5 mumol/g wet tissue and varied as much as 10-fold under the different test conditions. The levels of isopentenyl diphosphate isomerase, farnesyl diphosphate synthetase, and squalene synthetase were also measured in these animals. The changes in levels of these enzymes, in conjunction with the variation in substrate concentrations, are such that they could substantially influence the rate of cholesterol synthesis in liver.

  10. Suppression of CYP2B Induction by Alendronate-Mediated Farnesyl Diphosphate Synthase Inhibition in Primary Cultured Rat Hepatocytes

    PubMed Central

    Jackson, Nancy M.; Kocarek, Thomas A.

    2008-01-01

    We previously reported that squalestatin 1-mediated induction of CYP2B expression is attributable to squalene synthase inhibition and accumulation of an endogenous isoprenoid(s) that is capable of activating the constitutive androstane receptor. To determine whether squalestatin 1-mediated CYP2B induction is strictly dependent upon the biosynthesis of farnesyl pyrophosphate (FPP), the substrate for squalene synthase, the effects of alendronate, a nitrogen-containing bisphosphonate inhibitor of farnesyl diphosphate synthase, were determined on basal, squalestatin 1-inducible, and phenobarbital-inducible CYP2B expression in primary cultured rat hepatocytes. Alendronate treatment alone had no effect on CYP2B or CYP3A mRNA expression in the hepatocyte cultures, but alendronate co-treatment completely suppressed squalestatin 1-mediated CYP2B mRNA induction at concentrations (60 and 100 μM) that effectively inhibited cellular farnesyl diphosphate synthase activity, as assessed by reductions of squalestatin 1-mediated FPP accumulation, and that were not toxic to the cells, as indicated by a lack of effect on MTT activity. Alendronate co-treatment also partially suppressed phenobarbital-inducible CYP2B expression, and this suppressive effect was attenuated by additional co-treatment with the upstream pathway inhibitor, pravastatin. These findings demonstrate that squalestatin 1-mediated CYP2B induction cannot occur in the absence of FPP biosynthesis, but also indicate that one or more upstream isoprenoids, possibly isopentenyl pyrophosphate and/or dimethylallyl pyrophosphate, function to antagonize the CYP2B induction process. PMID:18617600

  11. Enlarging the scope of cell penetrating prenylated peptides to include farnesylated “CAAX” box sequences and diverse cell types

    PubMed Central

    Ochocki, Joshua D.; Igbavboa, Urule; Wood, W. Gibson; Wattenberg, Elizabeth V.; Distefano, Mark D.

    2010-01-01

    Protein prenylation is a post-translational modification that is present in a large number of proteins; it has been proposed to be responsible for membrane association and protein-protein interactions which contribute to its role in signal transduction pathways. Research has been aimed at inhibiting prenylation with farnesyltransferase inhibitors (FTIs) based on the finding that the farnesylated protein Ras is implicated in 30% of human cancers. Despite numerous studies on the enzymology of prenylation in vitro, many questions remain about the process of prenylation as it occurs in living cells. Here we describe the preparation of a series of farnesylated peptides that contain sequences recognized by protein farnesyltransferase. Using a combination of flow cytometry and confocal microscopy, we show that these peptides enter a variety of different cell types. A related peptide where the farnesyl group has been replaced by a disulfide-linked decyl group is also shown to be able to efficiently enter cells. These results highlight the applicability of these peptides as a platform for further study of protein prenylation and subsequent processing in live cells. PMID:20584014

  12. Silymarin Ameliorates Metabolic Dysfunction Associated with Diet-Induced Obesity via Activation of Farnesyl X Receptor

    PubMed Central

    Gu, Ming; Zhao, Ping; Huang, Jinwen; Zhao, Yuanyuan; Wang, Yahui; Li, Yin; Li, Yifei; Fan, Shengjie; Ma, Yue-Ming; Tong, Qingchun; Yang, Li; Ji, Guang; Huang, Cheng

    2016-01-01

    Background and purpose: Silymarin, a standardized extract of the milk thistle seeds, has been widely used to treat chronic hepatitis, cirrhosis, and other types of toxic liver damage. Despite increasing studies on the action of silymarin and its major active constituent, silybin in their therapeutic properties against insulin resistance, diabetes and hyperlipidaemia in vitro and in vivo, the mechanism underlying silymarin action remains unclear. Experimental approach: C57BL/6 mice were fed high-fat diet (HFD) for 3 months to induce obesity, insulin resistance, hyperlipidaemia, and fatty liver. These mice were then continuously treated with HFD alone or mixed with silymarin at 40 mg/100 g for additional 6 weeks. Biochemical analysis was used to test the serum lipid and bile acid profiles. Farnesyl X receptor (FXR) and nuclear factor kappa B (NF-κB) transactivities were analyzed in liver using a gene reporter assay based on quantitative RT-PCR. Key results: Silymarin treatment ameliorated insulin resistance, dyslipidaemia and inflammation, and reconstituted the bile acid pool in liver of diet-induced obesity. Associated with this, silybin and silymarin enhanced FXR transactivity. Consistently, in HepG2 cells, silybin inhibited NF-κB signaling, which was enhanced by FXR activation. Conclusion and implications: Our results suggest that silybin is an effective component of silymarin for treating metabolic syndrome by stimulating FXR signaling. PMID:27733832

  13. Geosmin biosynthesis. Streptomyces coelicolor germacradienol/germacrene D synthase converts farnesyl diphosphate to geosmin.

    PubMed

    Jiang, Jiaoyang; He, Xiaofei; Cane, David E

    2006-06-28

    Geosmin is responsible for the characteristic odor of moist soil. Incubation of recombinant germacradienol synthase, encoded by the SCO6073 (SC9B1.20) gene of the Gram-positive soil bacterium Streptomyces coelicolor, with farnesyl diphosphate (2, FPP) in the presence of Mg2+ gave a mixture of (4S,7R)-germacra-1(10)E,5E-diene-11-ol (3) (74%), (-)-(7S)-germacrene D (4) (10%), geosmin (1) (13%), and a hydrocarbon, tentatively assigned the structure of octalin 5 (3%). Individual incubations of recombinant germacradienol synthase with [1,1-2H2]FPP (2a), (1R)-[1-2H]-FPP (2b), and (1S)-[1-2H]-FPP (2c), as well as with FPP (2) in D2O, and GC-MS analysis of the resulting deuterated products supported a mechanism of geosmin formation involving proton-initiated cyclization and retro-Prins fragmentation of the initially formed germacradienol to give intermediate 5, followed by protonation of 5, 1,2-hydride shift, and capture of water.

  14. Cloning and characterization of farnesyl pyrophosphate synthase from the highly branched isoprenoid producing diatom Rhizosolenia setigera

    PubMed Central

    Ferriols, Victor Marco Emmanuel N.; Yaginuma, Ryoko; Adachi, Masao; Takada, Kentaro; Matsunaga, Shigeki; Okada, Shigeru

    2015-01-01

    The diatom Rhizosolenia setigera Brightwell produces highly branched isoprenoid (HBI) hydrocarbons that are ubiquitously present in marine environments. The hydrocarbon composition of R. setigera varies between C25 and C30 HBIs depending on the life cycle stage with regard to auxosporulation. To better understand how these hydrocarbons are biosynthesized, we characterized the farnesyl pyrophosphate (FPP) synthase (FPPS) enzyme of R. setigera. An isolated 1465-bp cDNA clone contained an open reading frame spanning 1299-bp encoding a protein with 432 amino acid residues. Expression of the RsFPPS cDNA coding region in Escherichia coli produced a protein that exhibited FPPS activity in vitro. A reduction in HBI content from diatoms treated with an FPPS inhibitor, risedronate, suggested that RsFPPS supplies precursors for HBI biosynthesis. Product analysis by gas chromatography-mass spectrometry also revealed that RsFPPS produced small amounts of the cis-isomers of geranyl pyrophosphate and FPP, candidate precursors for the cis-isomers of HBIs previously characterized. Furthermore, RsFPPS gene expression at various life stages of R. setigera in relation to auxosporulation were also analyzed. Herein, we present data on the possible role of RsFPPS in HBI biosynthesis, and it is to our knowledge the first instance that an FPPS was cloned and characterized from a diatom. PMID:25996801

  15. Farnesyl pyrophosphate synthase is the molecular target of nitrogen-containing bisphosphonates.

    PubMed

    van Beek, E; Pieterman, E; Cohen, L; Löwik, C; Papapoulos, S

    1999-10-14

    Bisphosphonates (Bps), inhibitors of osteoclastic bone resorption, are used in the treatment of skeletal disorders. Recent evidence indicated that farnesyl pyrophosphate (FPP) synthase and/or isopentenyl pyrophosphate (IPP) isomerase is the intracellular target(s) of bisphosphonate action. To examine which enzyme is specifically affected, we determined the effect of different Bps on incorporation of [(14)C]mevalonate (MVA), [(14)C]IPP, and [(14)C]dimethylallyl pyrophosphate (DMAPP) into polyisoprenyl pyrophosphates in a homogenate of bovine brain. HPLC analysis revealed that the three intermediates were incorporated into FPP and geranylgeranyl pyrophosphate (GGPP). In contrast to clodronate, the nitrogen-containing Bps (NBps), alendronate, risedronate, olpadronate, and ibandronate, completely blocked FPP and GGPP formation and induced in incubations with [(14)C]MVA a 3- to 5-fold increase in incorporation of label into IPP and/or DMAPP. Using a method that could distinguish DMAPP from IPP on basis of their difference in stability in acid, we found that none of the NBps affected the conversion of [(14)C]IPP into DMAPP, catalyzed by IPP isomerase, excluding this enzyme as target of NBp action. On the basis of these and our previous findings, we conclude that none of the enzymes up- or downstream of FPP synthase are affected by NBps, and FPP synthase is, therefore, the exclusive molecular target of NBp action.

  16. Farnesyl Pyrophosphate Is a Novel Pain-producing Molecule via Specific Activation of TRPV3*

    PubMed Central

    Bang, Sangsu; Yoo, Sungjae; Yang, Tae-Jin; Cho, Hawon; Hwang, Sun Wook

    2010-01-01

    Temperature-sensitive transient receptor potential ion channels (thermoTRPs) expressed in epidermal keratinocytes and sensory afferents play an important role as peripheral pain detectors for our body. Many natural and synthetic compounds have been found to act on the thermoTRPs leading to altered nociception, but little is known about endogenous painful molecules activating TRPV3. Here, we show that farnesyl pyrophosphate (FPP), an intermediate metabolite in the mevalonate pathway, specifically activates TRPV3 among six thermoTRPs using Ca2+ imaging and electrophysiology with cultured keratinocytes and TRPV3-overexpressing cells. Agonistic potencies of related compounds in the FPP metabolism were ignorable. Voltage-dependence of TRPV3 was shifted by FPP, which appears to be the activation mechanism. An intraplantar injection of FPP acutely elicits nociceptive behaviors in inflamed animals, indicating that FPP is a novel endogenous pain-producing substance via TRPV3 activation. Co-culture experiments demonstrated that this FPP-evoked signal in the keratinocytes is transmitted to sensory neurons. In addition, FPP reduced TRPV3 heat threshold resulting in heightened behavioral sensitivity to noxious heat. Taken together, our data suggest that FPP is the firstly identified endogenous TRPV3 activator that causes nociception. Our results may provide useful chemical information to elucidate TRPV3 physiology and novel pain-related metabolisms. PMID:20395302

  17. Regulation of the brain isoprenoids farnesyl- and geranylgeranylpyrophosphate is altered in male Alzheimer patients.

    PubMed

    Eckert, Gunter P; Hooff, Gero P; Strandjord, Dana M; Igbavboa, Urule; Volmer, Dietrich A; Müller, Walter E; Wood, W Gibson

    2009-08-01

    Post-translational modification of small GTPases by farnesyl- (FPP) and geranylgeranylpyrophosphate (GGPP) has generated much attention due to their potential contribution to cancer, cardiovascular and neurodegenerative diseases. Prenylated proteins have been identified in numerous cell functions and elevated levels of FPP and GGPP have been previously proposed to occur in Alzheimer disease (AD) but have never been quantified. In the present study, we determined if the mevalonate derived compounds FPP and GGPP are increased in brain grey and white matter of male AD patients as compared with control samples. This study demonstrates for the first time that FPP and GGPP levels are significantly elevated in human AD grey and white matter but not cholesterol, indicating a potentially disease-specific targeting of isoprenoid regulation independent of HMG-CoA-reductase. Further suggesting a selective disruption of FPP and GGPP homeostasis in AD, we show that inhibition of HMG-CoA reductase in vivo significantly reduced FPP, GGPP and cholesterol abundance in mice with the largest effect on the isoprenoids. A tentative conclusion is that if indeed regulation of FPP and GGPP is altered in AD brain such changes may stimulate protein prenylation and contribute to AD neuropathophysiology.

  18. Distribution of Endogenous Farnesyl Pyrophosphate and Four Species of Lysophosphatidic Acid in Rodent Brain

    PubMed Central

    Lee, Sung Ha; Raboune, Siham; Walker, J. Michael; Bradshaw, Heather B.

    2010-01-01

    Lysophosphatidic acid (LPA) is the umbrella term for lipid signaling molecules that share structural homology and activate the family of LPA receptors. Farnesyl Pyrophosphate (FPP) is commonly known as an intermediate in the synthesis of steroid hormones; however, its function as a signaling lipid is beginning to be explored. FPP was recently shown to an activator of the G-protein coupled receptor 92 (also known as LPA5) of the calcium channel TRPV3. The LPA receptors (including GPR92) are associated with the signal transduction of noxious stimuli, however, very little is known about the distribution of their signaling ligands (LPAs and FPP) in the brain. Here, using HPLC/MS/MS, we developed extraction and analytical methods for measuring levels of FPP and 4 species of LPA (palmitoyl, stearoyl, oleoyl and arachidonoyl-sn-glycerol-3 phosphate) in rodent brain. Relative distributions of each of the five compounds was significantly different across the brain suggesting divergent functionality for each as signaling molecules based on where and how much of each is being produced. Brainstem, midbrain, and thalamus contained the highest levels measured for each compound, though none in the same ratios while relatively small amounts were produced in cortex and cerebellum. These data provide a framework for investigations into functional relationships of these lipid ligands in specific brain areas, many of which are associated with the perception of pain. PMID:21152313

  19. Farnesyl pyrophosphate is a novel pain-producing molecule via specific activation of TRPV3.

    PubMed

    Bang, Sangsu; Yoo, Sungjae; Yang, Tae-Jin; Cho, Hawon; Hwang, Sun Wook

    2010-06-18

    Temperature-sensitive transient receptor potential ion channels (thermoTRPs) expressed in epidermal keratinocytes and sensory afferents play an important role as peripheral pain detectors for our body. Many natural and synthetic compounds have been found to act on the thermoTRPs leading to altered nociception, but little is known about endogenous painful molecules activating TRPV3. Here, we show that farnesyl pyrophosphate (FPP), an intermediate metabolite in the mevalonate pathway, specifically activates TRPV3 among six thermoTRPs using Ca(2+) imaging and electrophysiology with cultured keratinocytes and TRPV3-overexpressing cells. Agonistic potencies of related compounds in the FPP metabolism were ignorable. Voltage-dependence of TRPV3 was shifted by FPP, which appears to be the activation mechanism. An intraplantar injection of FPP acutely elicits nociceptive behaviors in inflamed animals, indicating that FPP is a novel endogenous pain-producing substance via TRPV3 activation. Co-culture experiments demonstrated that this FPP-evoked signal in the keratinocytes is transmitted to sensory neurons. In addition, FPP reduced TRPV3 heat threshold resulting in heightened behavioral sensitivity to noxious heat. Taken together, our data suggest that FPP is the firstly identified endogenous TRPV3 activator that causes nociception. Our results may provide useful chemical information to elucidate TRPV3 physiology and novel pain-related metabolisms.

  20. Characterization of a farnesyl diphosphate synthase gene from Penicillium brevicompactum MUCL 19011.

    PubMed

    Sharifirad, Atefeh; Mohammadian, Somayeh; Yakhchali, Bagher; Mehrpooyan, Sina; Fatemi, Seyed Safa-ali

    2016-01-01

    Farnesyl diphosphate synthase is a critical enzyme in the isoprenoids biosynthesis pathway responsible for ergosterol and secondary metabolites biosynthesis in fungi. Characterization of fds from Penicillium brevicompactum (Pbfds) was performed using TAIL-PCR and RT-PCR followed by complementation tests in Saccharomyces cerevisiae and determination of its expression profile by semi-quantitative RT-PCR. Promoter analysis suggests some binding sites for transcription factors some of which are involved in fungal growth and response to environmental stress. The Pbfds ORF encodes a cytosolic 39.7 kDa protein with a high conservation among Eurotiomycetes and the highest identity (96 %) with Pen. chrysogenum. Homology-based structural modeling suggests that the PbFDS is formed by the arrangement of 15 core helices around a large central cavity where the catalytic reaction takes place. Superimposition of the predicted 3D structure of the enzyme on its ortholog in human reveals the same folding pattern in the counterparts. The Pbfds expression may be stimulated in response to the environmental stresses and fungal growth and encodes the PBFDS--a cytosolic enzyme which with a key role in ergosterol and secondary metabolites biosynthesis.

  1. New insights into human farnesyl pyrophosphate synthase inhibition by second-generation bisphosphonate drugs

    NASA Astrophysics Data System (ADS)

    Fernández, D.; Ramis, R.; Ortega-Castro, J.; Casasnovas, R.; Vilanova, B.; Frau, J.

    2017-07-01

    Pamidronate, alendronate, APHBP and neridronate are a group of drugs, known as second-generation bisphosphonates (2G-BPs), commonly used in the treatment of bone-resorption disorders, and recently their use has been related to some collateral side effects. The therapeutic activity of 2G-BPs is related to the inhibition of the human Farnesyl Pyrophosphate Synthase (hFPPS). Available inhibitory activity values show that 2G-BPs act time-dependently, showing big differences in their initial inhibitory activities but similar final IC50 values. However, there is a lack of information explaining this similar final inhibitory potency. Although different residues have been identified in the stabilization of the R2 side chain of 2G-BPs into the active site, similar free binding energies were obtained that highlighted a similar stability of the ternary complexes, which in turns justified the similar IC50 values reported. Free binding energy calculations also demonstrated that the union of 2G-BPs to the active site were 38 to 54 kcal mol-1 energetically more favourable than the union of the natural substrate, which is the basis of the inhibition potency of the hFPPS activity.

  2. [Cloning and expression analysis of farnesyl pyrophosphate synthase from Aquilaria sinensis].

    PubMed

    Yang, Xin; Wei, Jian-He; Liu, Juan; Xu, Yan-Hong

    2013-10-01

    Farnesyl diphosphate synthase (FPS) is one of the key rate-limiting enzymes in the sesquiterpene metabolic pathways. In this study, the open reading frame (ORF) of FPS was cloned by PCR based on the transcript sequence of AsFPS1 from the Aquilaria sinensis transcriptome database and sequenced. Total RNA was extracted from the root, stem and leaves of three-year-old A. sinensis, and from healthy and wounded A. sinensis calli, and then reverse-transcribed into single-stranded cDNA as a template for real-time PCR, to detect the expression specificity of AsFPSI in different tissues and its expression profile in responding to different treatments. The result showed that the full length of AsFPS1 was 1 342 bp with the ORF 1 029 bp, encoding 342 amino acids. Tissue expression analysis indicated that AsFPS1 was mainly expressed in root and stem, and was lower in leaves. Inducible-experiments showed that the genes was induced by mechanical wound as well as chemical liquid induction, and reached the highest expression level at 6 h and 12 h, respectively. The full-length cDNA clone of AsFPSI and its expression patterns analysis will provide a foundation for follow-up study on its biological function and agarwood sesquiterpene biosynthesis mechanism.

  3. Cloning and characterization of farnesyl pyrophosphate synthase from the highly branched isoprenoid producing diatom Rhizosolenia setigera.

    PubMed

    Ferriols, Victor Marco Emmanuel N; Yaginuma, Ryoko; Adachi, Masao; Takada, Kentaro; Matsunaga, Shigeki; Okada, Shigeru

    2015-05-21

    The diatom Rhizosolenia setigera Brightwell produces highly branched isoprenoid (HBI) hydrocarbons that are ubiquitously present in marine environments. The hydrocarbon composition of R. setigera varies between C25 and C30 HBIs depending on the life cycle stage with regard to auxosporulation. To better understand how these hydrocarbons are biosynthesized, we characterized the farnesyl pyrophosphate (FPP) synthase (FPPS) enzyme of R. setigera. An isolated 1465-bp cDNA clone contained an open reading frame spanning 1299-bp encoding a protein with 432 amino acid residues. Expression of the RsFPPS cDNA coding region in Escherichia coli produced a protein that exhibited FPPS activity in vitro. A reduction in HBI content from diatoms treated with an FPPS inhibitor, risedronate, suggested that RsFPPS supplies precursors for HBI biosynthesis. Product analysis by gas chromatography-mass spectrometry also revealed that RsFPPS produced small amounts of the cis-isomers of geranyl pyrophosphate and FPP, candidate precursors for the cis-isomers of HBIs previously characterized. Furthermore, RsFPPS gene expression at various life stages of R. setigera in relation to auxosporulation were also analyzed. Herein, we present data on the possible role of RsFPPS in HBI biosynthesis, and it is to our knowledge the first instance that an FPPS was cloned and characterized from a diatom.

  4. Positive selection and functional divergence of farnesyl pyrophosphate synthase genes in plants.

    PubMed

    Qian, Jieying; Liu, Yong; Chao, Naixia; Ma, Chengtong; Chen, Qicong; Sun, Jian; Wu, Yaosheng

    2017-02-04

    Farnesyl pyrophosphate synthase (FPS) belongs to the short-chain prenyltransferase family, and it performs a conserved and essential role in the terpenoid biosynthesis pathway. However, its classification, evolutionary history, and the forces driving the evolution of FPS genes in plants remain poorly understood. Phylogeny and positive selection analysis was used to identify the evolutionary forces that led to the functional divergence of FPS in plants, and recombinant detection was undertaken using the Genetic Algorithm for Recombination Detection (GARD) method. The dataset included 68 FPS variation pattern sequences (2 gymnosperms, 10 monocotyledons, 54 dicotyledons, and 2 outgroups). This study revealed that the FPS gene was under positive selection in plants. No recombinant within the FPS gene was found. Therefore, it was inferred that the positive selection of FPS had not been influenced by a recombinant episode. The positively selected sites were mainly located in the catalytic center and functional areas, which indicated that the 98S and 234D were important positively selected sites for plant FPS in the terpenoid biosynthesis pathway. They were located in the FPS conserved domain of the catalytic site. We inferred that the diversification of FPS genes was associated with functional divergence and could be driven by positive selection. It was clear that protein sequence evolution via positive selection was able to drive adaptive diversification in plant FPS proteins. This study provides information on the classification and positive selection of plant FPS genes, and the results could be useful for further research on the regulation of triterpenoid biosynthesis.

  5. Crystallization and preliminary neutron diffraction experiment of human farnesyl pyrophosphate synthase complexed with risedronate

    PubMed Central

    Yokoyama, Takeshi; Ostermann, Andreas; Mizuguchi, Mineyuki; Niimura, Nobuo; Schrader, Tobias E.; Tanaka, Ichiro

    2014-01-01

    Nitrogen-containing bisphosphonates (N-BPs), such as risedronate and zoledronate, are currently used as a clinical drug for bone-resorption diseases and are potent inhibitors of farnesyl pyrophosphate synthase (FPPS). X-ray crystallographic analyses of FPPS with N-BPs have revealed that N-BPs bind to FPPS with three magnesium ions and several water molecules. To understand the structural characteristics of N-BPs bound to FPPS, including H atoms and hydration by water, neutron diffraction studies were initiated using BIODIFF at the Heinz Maier-Leibnitz Zentrum (MLZ). FPPS–risedronate complex crystals of approximate dimensions 2.8 × 2.5 × 1.5 mm (∼3.5 mm3) were obtained by repeated macro-seeding. Monochromatic neutron diffraction data were collected to 2.4 Å resolution with 98.4% overall completeness. Here, the first successful neutron data collection from FPPS in complex with N-BPs is reported. PMID:24699741

  6. Crystallization and preliminary neutron diffraction experiment of human farnesyl pyrophosphate synthase complexed with risedronate.

    PubMed

    Yokoyama, Takeshi; Ostermann, Andreas; Mizuguchi, Mineyuki; Niimura, Nobuo; Schrader, Tobias E; Tanaka, Ichiro

    2014-04-01

    Nitrogen-containing bisphosphonates (N-BPs), such as risedronate and zoledronate, are currently used as a clinical drug for bone-resorption diseases and are potent inhibitors of farnesyl pyrophosphate synthase (FPPS). X-ray crystallographic analyses of FPPS with N-BPs have revealed that N-BPs bind to FPPS with three magnesium ions and several water molecules. To understand the structural characteristics of N-BPs bound to FPPS, including H atoms and hydration by water, neutron diffraction studies were initiated using BIODIFF at the Heinz Maier-Leibnitz Zentrum (MLZ). FPPS-risedronate complex crystals of approximate dimensions 2.8 × 2.5 × 1.5 mm (∼3.5 mm(3)) were obtained by repeated macro-seeding. Monochromatic neutron diffraction data were collected to 2.4 Å resolution with 98.4% overall completeness. Here, the first successful neutron data collection from FPPS in complex with N-BPs is reported.

  7. Farnesyl pyrophosphate synthetase. Mechanistic studies of the 1'-4 coupling reaction with 2-fluorogeranyl pyrophosphate.

    PubMed

    Poulter, C D; Argyle, J C; Mash, E A

    1978-10-25

    The mechanism of the 1'-4 coupling reaction between isopentenyl pyrophosphate and geranyl pyrophosphate catalyzed by farnesyl pyrophosphate synthetase from porcine liver was studied with the allylic substrate analogue 2-fluorogeranyl pyrophosphate. 2-Fluorogeranyl pyrophosphate is an alternate substrate for the enzyme, yielding 6-fluorofarnesyl pyrophosphate upon condensation with isopentenyl pyrophosphate. The Michaelis constant for the fluoroanalogue, Km = 1.1 micron, is similar to that measured for geranyl pyrophosphate, Km = 0.7 micron. However, the rate of condensation with the fluoroanalogue was only 8.4 X 10(-4) that of the normal reaction. A similar rate of depression (4.4 X 10(-3)) was found for solvolysis of geranyl methanesulfonate and the corresponding 2-fluoro derivative, reactions known to proceed via cationic intermediates. In contrast, displacement of chlorine from geranyl chloride and 2-fluorogeranyl chloride by cyanide showed a small (2-fold) rate enhancement for the fluoro compound. Finally, 2-fluorogeranyl pyrophosphate is a competitive inhibitor against geranyl pyrophosphate. These data are interpreted in terms of an ionization-condensation-elimination mechanism for the 1'-4 coupling reaction.

  8. Farnesylated and methylated KRAS4b: high yield production of protein suitable for biophysical studies of prenylated protein-lipid interactions

    PubMed Central

    Gillette, William K.; Esposito, Dominic; Abreu Blanco, Maria; Alexander, Patrick; Bindu, Lakshman; Bittner, Cammi; Chertov, Oleg; Frank, Peter H.; Grose, Carissa; Jones, Jane E.; Meng, Zhaojing; Perkins, Shelley; Van, Que; Ghirlando, Rodolfo; Fivash, Matthew; Nissley, Dwight V.; McCormick, Frank; Holderfield, Matthew; Stephen, Andrew G.

    2015-01-01

    Prenylated proteins play key roles in several human diseases including cancer, atherosclerosis and Alzheimer’s disease. KRAS4b, which is frequently mutated in pancreatic, colon and lung cancers, is processed by farnesylation, proteolytic cleavage and carboxymethylation at the C-terminus. Plasma membrane localization of KRAS4b requires this processing as does KRAS4b-dependent RAF kinase activation. Previous attempts to produce modified KRAS have relied on protein engineering approaches or in vitro farnesylation of bacterially expressed KRAS protein. The proteins produced by these methods do not accurately replicate the mature KRAS protein found in mammalian cells and the protein yield is typically low. We describe a protocol that yields 5–10 mg/L highly purified, farnesylated, and methylated KRAS4b from insect cells. Farnesylated and methylated KRAS4b is fully active in hydrolyzing GTP, binds RAF-RBD on lipid Nanodiscs and interacts with the known farnesyl-binding protein PDEδ. PMID:26522388

  9. Cytosolic glutathione transferases from rat liver. Primary structure of class alpha glutathione transferase 8-8 and characterization of low-abundance class Mu glutathione transferases.

    PubMed Central

    Alin, P; Jensson, H; Cederlund, E; Jörnvall, H; Mannervik, B

    1989-01-01

    Six GSH transferases with neutral/acidic isoelectric points were purified from the cytosol fraction of rat liver. Four transferases are class Mu enzymes related to the previously characterized GSH transferases 3-3, 4-4 and 6-6, as judged by structural and enzymic properties. Two additional GSH transferases are distinguished by high specific activities with 4-hydroxyalk-2-enals, toxic products of lipid peroxidation. The most abundant of these two enzymes, GSH transferase 8-8, a class Alpha enzyme, has earlier been identified in rat lung and kidney. The amino acid sequence of subunit 8 was determined and showed a typical class Alpha GSH transferase structure including an N-acetylated N-terminal methionine residue. PMID:2775231

  10. Purification and characterization of the Oligosaccharyl transferase

    SciTech Connect

    Kapoor, T.M.

    1990-11-01

    Oligosaccharyl transferase was characterized to be a glycoprotein with at least one saccharide unit that had a D-manno or D- glucopyranose configuration with unmodified hydroxy groups at C-3, C-4 and C-6, using a Concanavalin A affinity column. This afforded a 100 fold increase in the transferase purity in the solubilized microsomal sample and also removed over 90% of the microsomal proteins (the cytosolic ones being removed before solubilization). The detergent, N,N-Dimethyldodecylamine N-oxide (LDAO) was used for solubilization and it yielded a system compatible with the assay and the purification steps. An efficient method for detergent extraction without dilution of sample or protein precipitation was also developed.

  11. Skin Metabolite, Farnesyl Pyrophosphate, Regulates Epidermal Response to Inflammation, Oxidative Stress, and Migration.

    PubMed

    Pastar, Irena; Stojadinovic, Olivera; Sawaya, Andrew P; Stone, Rivka C; Lindley, Linsey E; Ojeh, Nkemcho; Vukelic, Sasa; Samuels, Herbert H; Tomic-Canic, Marjana

    2016-11-01

    Skin produces cholesterol and a wide array of sterols and non-sterol mevalonate metabolites, including isoprenoid derivative farnesyl pyrophosphate (FPP). To characterize FPP action in epidermis, we generated transcriptional profiles of primary human keratinocytes treated with zaragozic acid (ZGA), a squalene synthase inhibitor that blocks conversion of FPP to squalene resulting in endogenous accumulation of FPP. The elevated levels of intracellular FPP resulted in regulation of epidermal differentiation and adherens junction signaling, insulin growth factor (IGF) signaling, oxidative stress response and interferon (IFN) signaling. Immunosuppressive properties of FPP were evidenced by STAT-1 downregulation and prominent suppression of its nuclear translocation by IFNγ. Furthermore, FPP profoundly downregulated genes involved in epidermal differentiation of keratinocytes in vitro and in human skin ex vivo. Elevated levels of FPP resulted in induction of cytoprotective transcriptional factor Nrf2 and its target genes. We have previously shown that FPP functions as ligand for the glucocorticoid receptor (GR), one of the major regulator of epidermal homeostasis. Comparative microarray analyses show significant but not complete overlap between FPP and glucocorticoid regulated genes, suggesting that FPP may have wider transcriptional impact. This was further supported by co-transfection and chromatin immunoprecipitation experiments where we show that upon binding to GR, FPP recruits β-catenin and, unlike glucocorticoids, recruits co-repressor GRIP1 to suppress keratin 6 gene. These findings have many clinical implications related to epidermal lipid metabolism, response to glucocorticoid therapy as well as pleiotropic effects of cholesterol lowering therapeutics, statins. J. Cell. Physiol. 231: 2452-2463, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Farnesyl phosphatase, a Corpora allata enzyme involved in juvenile hormone biosynthesis in Aedes aegypti.

    PubMed

    Nyati, Pratik; Nouzova, Marcela; Rivera-Perez, Crisalejandra; Clifton, Mark E; Mayoral, Jaime G; Noriega, Fernando G

    2013-01-01

    The juvenile hormones (JHs) are sesquiterpenoid compounds that play a central role in insect reproduction, development and behavior. The late steps of JH III biosynthesis in the mosquito Aedes aegypti involve the hydrolysis of farnesyl pyrophosphate (FPP) to farnesol (FOL), which is then successively oxidized to farnesal and farnesoic acid, methylated to form methyl farnesoate and finally transformed to JH III by a P450 epoxidase. The only recognized FPP phosphatase (FPPase) expressed in the corpora allata (CA) of an insect was recently described in Drosophila melanogaster (DmFPPase). In the present study we sought to molecularly and biochemically characterize the FPP phosphatase responsible for the transformation of FPP into FOL in the CA of A. aegypti. A search for orthologs of the DmFPPase in Aedes aegypti led to the identification of 3 putative FPPase paralogs expressed in the CA of the mosquito (AaFPPases-1, -2, and -3). The activities of recombinant AaFPPases were tested against general phosphatase substrates and isoprenoid pyrophosphates. Using a newly developed assay utilizing fluorescent tags, we analyzed AaFPPase activities in CA of sugar and blood-fed females. Double-stranded RNA (dsRNA) was used to evaluate the effect of reduction of AaFPPase mRNAs on JH biosynthesis. AaFPPase-1 and AaFPPase-2 are members of the NagD family of the Class IIA C2 cap-containing haloalkanoic acid dehalogenase (HAD) super family and efficiently hydrolyzed FPP into FOL. AaFPPase activities were different in CA of sugar and blood-fed females. Injection of dsRNAs resulted in a significant reduction of AaFPPase-1 and AaFPPase-2 mRNAs, but only reduction of AaFPPase-1 caused a significant decrease of JH biosynthesis. These results suggest that AaFPPase-1 is predominantly involved in the catalysis of FPP into FOL in the CA of A. aegypti.

  13. Rubber transferase in guayule plants. [Parthenium argentatum

    SciTech Connect

    Rosenfield, C.L.; Foster, M.A.; Benedict, C.R.

    1986-04-01

    Rubber transferase catalyzes the transfer of cis-1,4-polyprenyl-PP to isopentenyl-PP (IPP) with the elimination of PP/sub i/. Rubber transferase activity in guayule (Parthenium argentatum Gray) stems was localized in the lipid fraction of the homogenate following centrifugation in buffer and 0.4M Mannitol. Washed rubber particles were obtained by the chromatography of the lipid fraction on Ultrogel columns with an exclusion limit of 750,000 daltons by the procedure of B.G. Audley (private communication). The rubber particles catalyzed the incorporation of /sup 14/C-IPP into cis-polyisoprene. The radioactive cis-polyisoprene was identified by ozonolysis and chromatography of the resulting /sup 14/C-levulinic acid. The synthesis of cis-polyisoprene in the rubber particles required Mg/sup 2 +/ and IPP and was stimulated 2-fold with the addition of DMAPP. Rubber synthesis in guayule plants growing in the Permian Basin of West Texas does not occur during summer months but is induced by the cold night temperatures of the fall and winter. From August to December individual plants (which were transplanted in May) accumulated from 66mg to 11,800mg or rubber. During this period there was a 4-fold increase in rubber transferase activity in stem homogenates induced by the low temperatures.

  14. Farnesyl biliverdins IXα are novel ligands of biliproteins from moths of the Noctuoidea superfamily: A chemosystematic view of the Lepidoptera.

    PubMed

    Kayser, Hartmut; Nimtz, Manfred

    2016-11-01

    Bilins, derived from biliverdin IXα, are known from animals, plants and microorganisms, where they play vital roles as light-absorbing pigments. Bilins occur also in many insects. Recently, we discovered in insects a novel structural type of bilins with a farnesyl substituent at pyrrole ring A of biliverdin IXα. The first of these unusual bilins with a molecular mass of 852 (C48H60O10N4) was identified in Cerura vinula, subsequently in Spodoptera littoralis; both species are members of the Noctuoidea superfamily of moths. From an evolutionary point of view, it was of interest to examine other species and families of this monophyletic clade. Here, we show that other moths species in this clade (three Notodontidae species, one Erebidae species, and one Noctuidae species) have farnesylated biliverdins IXα that are present as a mixture of three bilins, differing by the number of oxygen atoms (O8-10). These bilins are associated with typical hemolymph storage proteins, which were identified by mass spectroscopic sequencing of tryptic peptides as arylphorins (a class of 500-kDa hexamerins) in the Notodontidae and Erebidae families, and as 350-kDa very high-density lipoproteins in the Noctuidae family. Circular dichroism spectroscopy revealed that the bilins adopt opposite conformations in complex with the two different classes of proteins. At present, farnesylated biliverdins and IXα-isomers of bilins in general are known only from species of the Noctuoidea clade; the sister clades of Bombycoidea and Papilionoidea synthesise the IXγ-isomer of biliverdin and derivatives thereof. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Prenylome profiling reveals S-farnesylation is crucial for membrane targeting and antiviral activity of ZAP long-isoform.

    PubMed

    Charron, Guillaume; Li, Melody M H; MacDonald, Margaret R; Hang, Howard C

    2013-07-02

    S-prenylation is an important lipid modification that targets proteins to membranes for cell signaling and vesicle trafficking in eukaryotes. As S-prenylated proteins are often key effectors for oncogenesis, congenital disorders, and microbial pathogenesis, robust proteomic methods are still needed to biochemically characterize these lipidated proteins in specific cell types and disease states. Here, we report that bioorthogonal proteomics of macrophages with an improved alkyne-isoprenoid chemical reporter enables large-scale profiling of prenylated proteins, as well as the discovery of unannotated lipidated proteins such as isoform-specific S-farnesylation of zinc-finger antiviral protein (ZAP). Notably, S-farnesylation was crucial for targeting the long-isoform of ZAP (ZAPL/PARP-13.1/zc3hav1) to endolysosomes and enhancing the antiviral activity of this immune effector. These studies demonstrate the utility of isoprenoid chemical reporters for proteomic analysis of prenylated proteins and reveal a role for protein prenylation in host defense against viral infections.

  16. [A 13-week subcutaneous toxicity study of prednisolone farnesylate (PNF) in rats].

    PubMed

    Okazaki, S; Yamazaki, E; Tamura, K; Hoshiya, T; Anabuki, K; Tanaka, H; Tanaka, G

    1992-11-01

    The toxicity of Prednisolone farnesylate (PNF), a synthetic glucocorticoid, was investigated in the Sprague-Dawley rat. PNF was injected subcutaneously at doses of 0.03, 0.3, 3 and 30 mg/kg/day for 13 weeks. In addition, 18.7 mg/kg/day prednisolone (PN), which is approximate to 30 mg/kg/day PNF in prednisolone molarity, was also administered to the rat for comparison. The results are summarized as follows: 1. All animals from the PN 18.7 mg/kg/day group, and four(4) out of ten(10) males and three(3) out of ten(10) females from the PNF 30 mg/kg/day group died having shown weakened condition such as unkempt fur and emaciation. Histopathologically, systemic suppurative inflammation, as shown by pyeronephritis and abscess formation in many organs and tissues, was observed and it was considered that the administration of steroid induced weakened condition and systemic suppuration which resulted in death. In addition, atrophy was noted in the adrenal glands, lymphatic organs and skin, and histopathological lesions were also observed in the lungs, liver, pancreatic islets, bone, bone marrow and mammary glands. 2. Surviving animals in the PNF 30 mg/kg/day group showed almost the same changes as those observed in the dead animals that died. Hematological examination revealed an anemic change and a decrease in lymphocytes with an increase in segmented neutrophils and eosinophils. In the urinalysis and blood chemistry, the changes suggesting damages to the liver and kidneys were mainly observed. 3. In the PNF 3 and 0.3 mg/kg/day groups, several changes such as atrophy of the adrenal glands, lymphatic organs and skin were noted in a dose dependent manner. 4. In the PNF 0.03 mg/kg/day group, ther were no toxic signs. 5. Based on these results, it was concluded that the overt toxic dose of PNF was 0.3 mg/kg/day and the non-toxic dose was 0.03 mg/kg/day in the present study.

  17. Chromatofocusing of glutathione S-transferases from human kidney.

    PubMed

    Koskelo, K; Icén, A

    1984-04-01

    The glutathione S-transferase isoenzyme patterns of four human kidneys have been determined by chromatofocusing. The elution profiles were essentially similar in each tissue. Two major basic transferases and one acidic were partially characterized. All three were inhibited by bilirubin but considerable differences were found in the rate and extent of inactivation. The molecular weights, KM values and pH optima were similar to the values for transferases from other tissues. Chromatofocusing was found to be effective for the separation and purification of human glutathione transferases.

  18. Blocking protein farnesylation improves nuclear shape abnormalities in keratinocytes of mice expressing the prelamin A variant in Hutchinson-Gilford progeria syndrome.

    PubMed

    Wang, Yuexia; Ostlund, Cecilia; Worman, Howard J

    2010-01-01

    Hutchinson-Gilford progeria syndrome (HGPS) is an accelerated aging disorder caused by mutations in LMNA leading to expression of a truncated prelamin A variant termed progerin. Whereas a farnesylated polypeptide is normally removed from the carboxyl-terminus of prelamin A during endoproteolytic processing to lamin A, progerin lacks the cleavage site and remains farnesylated. Cultured cells from human subjects with HGPS and genetically modified mice expressing progerin have nuclear morphological abnormalities, which are reversed by inhibitors of protein farnesylation. In addition, treatment with protein farnesyltransferase inhibitors improves whole animal phenotypes in mouse models of HGPS. However, improvement in nuclear morphology in tissues after treatment of animals has not been demonstrated. We therefore treated transgenic mice that express progerin in epidermis with the protein farnesyltransferase inhibitor FTI-276 or a combination of pravastatin and zoledronate to determine if they reversed nuclear morphological abnormalities in tissue. Immunofluorescence microscopy and "blinded" electron microscopic analysis demonstrated that systemic administration of FTI-276 or pravastatin plus zoledronate significantly improved nuclear morphological abnormalities in keratinocytes of transgenic mice. These results show that pharmacological blockade of protein prenylation reverses nuclear morphological abnormalities that occur in HGPS in vivo. They further suggest that skin biopsy may be useful to determine if protein farnesylation inhibitors are exerting effects in subjects with HGPS in clinical trials.

  19. Posttranslational modification of Ha-ras p21 by farnesyl versus geranylgeranyl isoprenoids is determined by the COOH-terminal amino acid.

    PubMed Central

    Kinsella, B T; Erdman, R A; Maltese, W A

    1991-01-01

    ras proteins undergo posttranslational modification by a 15-carbon farnesyl isoprenoid at a cysteine within a defined COOH-terminal amino acid motif; i.e., Cys-Ali-Ali-Ser/Met (where Ali represents an aliphatic residue). In other low molecular mass GTP-binding proteins, cysteines are modified by 20-carbon geranylgeranyl groups within a Cys-Ali-Ali-Leu motif. We changed the terminal Ser-189 of Ha-ras p21 to Leu-189 by site-directed mutagenesis and found that the protein was modified by [3H]geranylgeranyl instead of [3H]farnesyl in an in vitro assay. Gel-permeation chromatography of [3H]mevalonate-labeled hydrocarbons released from immunoprecipitated ras proteins overexpressed in COS cells indicated that Ha-ras p21(Leu-189) was also a substrate for 20-carbon isoprenyl modification in vivo. Additional steps in Ha-ras p21 processing, normally initiated by farnesylation, appear to be supported by geranylgeranylation, based on metabolic labeling of Ha-ras p21(Leu-189) with [3H]palmitate and its subcellular localization in a particulate fraction from COS cells. These observations indicate that the amino acid occupying the terminal position (Xaa) in the Cys-Ali-Ali-Xaa motif constitutes a key structural feature by which Ha-ras p21 and other proteins with ras-like COOH-terminal isoprenylation sites are distinguished as substrates for farnesyl- or geranylgeranyltransferases. Images PMID:1924354

  20. Glutathione-S-transferase selective release of metformin from its sulfonamide prodrug.

    PubMed

    Rautio, Jarkko; Vernerová, Monika; Aufderhaar, Imke; Huttunen, Kristiina M

    2014-11-01

    In this study, three sulfonamide prodrugs of metformin were designed and synthesized. The bioconversion of the sulfonamide prodrugs by glutathione-S-transferase (GST) was evaluated in rat and human liver S9 fractions as well as with recombinant human GST forms. One of the prodrugs (3) was bioactivated by GST and released metformin in a quantitative manner, whereas the two others were enzymatically stable. Prodrug 3 had a much higher logD value relative to metformin and it was reasonably stable in both acidic buffer and rat small intestine homogenate, which indicates that this prodrug has the potential to increase the oral absorption of metformin.

  1. Structure of human farnesyl pyrophosphate synthase in complex with an aminopyridine bisphosphonate and two molecules of inorganic phosphate

    SciTech Connect

    Park, Jaeok; Lin, Yih-Shyan; Tsantrizos, Youla S.; Berghuis, Albert M.

    2014-02-19

    A co-crystal structure of human farnesyl pyrophosphate synthase in complex with an aminopyridine bisphosphonate, YS0470, and two molecules of inorganic phosphate has been determined. The identity of the phosphate ligands was confirmed by anomalous diffraction data. Human farnesyl pyrophosphate synthase (hFPPS) produces farnesyl pyrophos@@phate, an isoprenoid essential for a variety of cellular processes. The enzyme has been well established as the molecular target of the nitrogen-containing bisphosphonates (N-BPs), which are best known for their antiresorptive effects in bone but are also known for their anticancer properties. Crystal structures of hFPPS in ternary complexes with a novel bisphosphonate, YS0470, and the secondary ligands inorganic phosphate (P{sub i}), inorganic pyrophosphate (PP{sub i}) and isopentenyl pyrophosphate (IPP) have recently been reported. Only the co-binding of the bisphosphonate with either PP{sub i} or IPP resulted in the full closure of the C-@@terminal tail of the enzyme, a conformational change that is required for catalysis and that is also responsible for the potent in vivo efficacy of N-BPs. In the present communication, a co-crystal structure of hFPPS in complex with YS0470 and two molecules of P{sub i} is reported. The unusually close proximity between these ligands, which was confirmed by anomalous diffraction data, suggests that they interact with one another, with their anionic charges neutralized in their bound state. The structure also showed the tail of the enzyme to be fully disordered, indicating that simultaneous binding of two P{sub i} molecules with a bisphosphonate cannot induce the tail-closing conformational change in hFPPS. Examination of homologous FPPSs suggested that this ligand-dependent tail closure is only conserved in the mammalian proteins. The prevalence of P{sub i}-bound hFPPS structures in the PDB raises a question regarding the in vivo relevance of P{sub i} binding to the function of the enzyme.

  2. Formation of a Novel Macrocyclic Alkaloid from the Unnatural Farnesyl Diphosphate Analogue Anilinogeranyl Diphosphate by 5-Epi-Aristolochene Synthase

    PubMed Central

    Rising, Kathleen A.; Crenshaw, Charisse M.; Koo, Hyun Jo; Subramanian, Thangaiah; Chehade, Kareem A. H.; Starks, Courtney; Allen, Keith D.; Andres, Douglas A.; Spielmann, H. Peter; Noel, Joseph P.; Chappell, Joe

    2015-01-01

    As part of an effort to identify substrate analogs suitable for helping to resolve structural features important for terpene synthases, the inhibition of 5-epi-aristolochene biosynthesis from farnesyl diphosphate (FPP) by the tobacco 5-epi-aristolochene synthase incubated with anilinogeranyl diphosphate (AGPP) was examined. The apparent noncompetitive nature of the inhibition supported further assessment of how AGPP might be bound to crystallographic forms of the enzyme. Surprisingly, the bound form of the inhibitor appeared to have undergone a cyclization event consistent with the native mechanism associated with FPP catalysis. Biocatalytic formation of a novel 13-membered macrocyclic paracyclophane alkaloid was confirmed by high-resolution GC-MS and NMR analysis. This work provides insights into new biosynthetic means for generating novel, functionally diversified, medium-sized terpene alkaloids. PMID:25897591

  3. Genomic organization and expression analysis of a farnesyl diphosphate synthase gene (FPPS2) in apples (Malus domestica Borkh.).

    PubMed

    Yuan, Kejun; Wang, Changjun; Xin, Li; Zhang, Anning; Ai, Chengxiang

    2013-07-25

    A farnesyl diphosphate synthase gene (FPPS2), which contains 11 introns and 12 exons, was isolated from the apple cultivar "White Winter Pearmain". When it was compared to our previously reported FPPS1, its each intron size was different, its each exon size was the same as that of FPPS1 gene, 30 nucleotide differences were found in its coding sequence. Based on these nucleotide differences, specific primers were designed to perform expression analysis; the results showed that it expressed in both fruit and leaf, its expression level was obviously lower than that of FPPS1 gene in fruit which was stored at 4°C for 5 weeks. This is the first report concerning two FPPS genes and their expression comparison in apples. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Photoactive analogs of farnesyl diphosphate and related isoprenoids: design and applications in studies of medicinally important isoprenoid-utilizing enzymes.

    PubMed

    Vervacke, Jeffrey S; Wang, Yen-Chih; Distefano, Mark D

    2013-01-01

    Farnesyl diphosphate (FPP) is an important metabolic intermediate in the biosynthesis of a variety of molecules including sesquiterpenes and the side chains of a number of cofactors. FPP is also the source of isoprenoid side chains found attached to proteins. Enzymes that employ FPP as a substrate are of interest because they are involved in the semisynthesis of drugs as well as targets for drug design. Photoactive analogs of FPP have been useful for identifying enzymes that use this molecule as a substrate. A variety of photocrosslinking groups have been employed to prepare FPP analogs for use in such experiments including aryl azides, diazotrifluoropropionates and benzophenones. In this review, the design of these probes is described along with an examination of how they have been used in crosslinking experiments.

  5. The Early-Acting Peroxin PEX19 Is Redundantly Encoded, Farnesylated, and Essential for Viability in Arabidopsis thaliana

    PubMed Central

    McDonnell, Margaret M.; Burkhart, Sarah E.; Stoddard, Jerrad M.; Wright, Zachary J.; Strader, Lucia C.; Bartel, Bonnie

    2016-01-01

    Peroxisomes are single-membrane bound organelles that are essential for normal development in plants and animals. In mammals and yeast, the peroxin (PEX) proteins PEX3 and PEX19 facilitate the early steps of peroxisome membrane protein (PMP) insertion and pre-peroxisome budding from the endoplasmic reticulum. The PEX3 membrane protein acts as a docking site for PEX19, a cytosolic chaperone for PMPs that delivers PMPs to the endoplasmic reticulum or peroxisomal membrane. PEX19 is farnesylated in yeast and mammals, and we used immunoblotting with prenylation mutants to show that PEX19 also is fully farnesylated in wild-type Arabidopsis thaliana plants. We examined insertional alleles disrupting either of the two Arabidopsis PEX19 isoforms, PEX19A or PEX19B, and detected similar levels of PEX19 protein in the pex19a-1 mutant and wild type; however, PEX19 protein was nearly undetectable in the pex19b-1 mutant. Despite the reduction in PEX19 levels in pex19b-1, both pex19a-1 and pex19b-1 single mutants lacked notable peroxisomal β-oxidation defects and displayed normal levels and localization of peroxisomal matrix and membrane proteins. The pex19a-1 pex19b-1 double mutant was embryo lethal, indicating a redundantly encoded critical role for PEX19 during embryogenesis. Expressing YFP-tagged versions of either PEX19 isoform rescued this lethality, confirming that PEX19A and PEX19B act redundantly in Arabidopsis. We observed that pex19b-1 enhanced peroxisome-related defects of a subset of peroxin-defective mutants, supporting a role for PEX19 in peroxisome function. Together, our data indicate that Arabidopsis PEX19 promotes peroxisome function and is essential for viability. PMID:26824478

  6. Structural and thermodynamic basis of the inhibition of Leishmania major farnesyl diphosphate synthase by nitrogen-containing bisphosphonates

    SciTech Connect

    Aripirala, Srinivas; Gonzalez-Pacanowska, Dolores; Oldfield, Eric; Kaiser, Marcel; Amzel, L. Mario; Gabelli, Sandra B.

    2014-03-01

    Structural insights into L. major farnesyl diphosphate synthase, a key enzyme in the mevalonate pathway, are described. Farnesyl diphosphate synthase (FPPS) is an essential enzyme involved in the biosynthesis of sterols (cholesterol in humans and ergosterol in yeasts, fungi and trypanosomatid parasites) as well as in protein prenylation. It is inhibited by bisphosphonates, a class of drugs used in humans to treat diverse bone-related diseases. The development of bisphosphonates as antiparasitic compounds targeting ergosterol biosynthesis has become an important route for therapeutic intervention. Here, the X-ray crystallographic structures of complexes of FPPS from Leishmania major (the causative agent of cutaneous leishmaniasis) with three bisphosphonates determined at resolutions of 1.8, 1.9 and 2.3 Å are reported. Two of the inhibitors, 1-(2-hydroxy-2,2-diphosphonoethyl)-3-phenylpyridinium (300B) and 3-butyl-1-(2,2-diphosphonoethyl)pyridinium (476A), co-crystallize with the homoallylic substrate isopentenyl diphosphate (IPP) and three Ca{sup 2+} ions. A third inhibitor, 3-fluoro-1-(2-hydroxy-2,2-diphosphonoethyl)pyridinium (46I), was found to bind two Mg{sup 2+} ions but not IPP. Calorimetric studies showed that binding of the inhibitors is entropically driven. Comparison of the structures of L. major FPPS (LmFPPS) and human FPPS provides new information for the design of bisphosphonates that will be more specific for inhibition of LmFPPS. The asymmetric structure of the LmFPPS–46I homodimer indicates that binding of the allylic substrate to both monomers of the dimer results in an asymmetric dimer with one open and one closed homoallylic site. It is proposed that IPP first binds to the open site, which then closes, opening the site on the other monomer, which closes after binding the second IPP, leading to the symmetric fully occupied FPPS dimer observed in other structures.

  7. Suppressing Farnesyl Diphosphate Synthase Alters Chloroplast Development and Triggers Sterol-Dependent Induction of Jasmonate- and Fe-Related Responses.

    PubMed

    Manzano, David; Andrade, Paola; Caudepón, Daniel; Altabella, Teresa; Arró, Montserrat; Ferrer, Albert

    2016-09-01

    Farnesyl diphosphate synthase (FPS) catalyzes the synthesis of farnesyl diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate. Arabidopsis (Arabidopsis thaliana) contains two genes (FPS1 and FPS2) encoding FPS. Single fps1 and fps2 knockout mutants are phenotypically indistinguishable from wild-type plants, while fps1/fps2 double mutants are embryo lethal. To assess the effect of FPS down-regulation at postembryonic developmental stages, we generated Arabidopsis conditional knockdown mutants expressing artificial microRNAs devised to simultaneously silence both FPS genes. Induction of silencing from germination rapidly caused chlorosis and a strong developmental phenotype that led to seedling lethality. However, silencing of FPS after seed germination resulted in a slight developmental delay only, although leaves and cotyledons continued to show chlorosis and altered chloroplasts. Metabolomic analyses also revealed drastic changes in the profile of sterols, ubiquinones, and plastidial isoprenoids. RNA sequencing and reverse transcription-quantitative polymerase chain reaction transcriptomic analysis showed that a reduction in FPS activity levels triggers the misregulation of genes involved in biotic and abiotic stress responses, the most prominent one being the rapid induction of a set of genes related to the jasmonic acid pathway. Down-regulation of FPS also triggered an iron-deficiency transcriptional response that is consistent with the iron-deficient phenotype observed in FPS-silenced plants. The specific inhibition of the sterol biosynthesis pathway by chemical and genetic blockage mimicked these transcriptional responses, indicating that sterol depletion is the primary cause of the observed alterations. Our results highlight the importance of sterol homeostasis for normal chloroplast development and function and reveal important clues about how isoprenoid and sterol metabolism is integrated within plant physiology and development.

  8. Synthesis, Properties and Applications of Diazotrifluropropanoyl-Containing Photoactive Analogues of Farnesyl Diphosphate Containing Modified Linkages for Enhanced Stability

    PubMed Central

    Hovlid, Marisa L.; Edelstein, Rebecca L.; Henry, Olivier; Ochocki, Joshua; DeGraw, Amanda; Lenevich, Stepan; Talbot, Trista; Young, Victor G.; Hruza, Alan W.; Lopez-Gallego, Fernando; Labello, Nicholas P.; Strickland, Corey L.; Schmidt-Dannert, Claudia; Distefano, Mark D.

    2009-01-01

    Photoactive analogues of farnesyl diphosphate (FPP) are useful probes in studies of enzymes that employ this molecule as a substrate. Here, we describe the preparation and properties of two new FPP analogues that contain diazotrifluoropropionyl photophores linked to geranyl diphosphate via amide or ester linkages. The amide-linked analogue (3) was synthesized in 32P-labeled form from geraniol in 7 steps. Experiments with Saccharomyces cerevisiae protein farnesyltransferase (ScPFTase) showed that 3 is an alternative substrate for the enzyme. Photolysis experiments with [32P]3 demonstrate that this compound labels the β-subunits of both farnesyl- and geranylgeranyltransferase (types 1 and 2). However, the amide-linked probe 3 undergoes a rearrangement to a photochemically unreactive isomeric triazolone upon long term storage making it inconvenient to use. To address this stability issue, the ester-linked analogue 4 was prepared in 6 steps from geraniol. Computational analysis and X-ray crystallographic studies suggest that 4 binds to PFTase in a similar fashion as FPP. Compound 4 is also an alternative substrate for PFTase and a 32P-labeled form selectively photocrosslinks the β-subunit of ScPFTase as well as E. coli farnesyldiphosphate synthase and a germacrene-producing sesquiterpene synthase from Nostoc sp. strain PCC7120 (a cyanobacterial source). Finally, nearly exclusive labeling of ScPFTase in crude E. coli extract was observed, suggesting that [32P]4 manifests significant selectivity and should hence be useful for identifying novel FPP utilizing enzymes in crude protein preparations. PMID:19954434

  9. The Genetic Architecture of Murine Glutathione Transferases

    PubMed Central

    Lu, Lu; Pandey, Ashutosh K.; Houseal, M. Trevor; Mulligan, Megan K.

    2016-01-01

    Glutathione S-transferase (GST) genes play a protective role against oxidative stress and may influence disease risk and drug pharmacokinetics. In this study, massive multiscalar trait profiling across a large population of mice derived from a cross between C57BL/6J (B6) and DBA2/J (D2)—the BXD family—was combined with linkage and bioinformatic analyses to characterize mechanisms controlling GST expression and to identify downstream consequences of this variation. Similar to humans, mice show a wide range in expression of GST family members. Variation in the expression of Gsta4, Gstt2, Gstz1, Gsto1, and Mgst3 is modulated by local expression QTLs (eQTLs) in several tissues. Higher expression of Gsto1 in brain and liver of BXD strains is strongly associated (P < 0.01) with inheritance of the B6 parental allele whereas higher expression of Gsta4 and Mgst3 in brain and liver, and Gstt2 and Gstz1 in brain is strongly associated with inheritance of the D2 parental allele. Allele-specific assays confirmed that expression of Gsto1, Gsta4, and Mgst3 are modulated by sequence variants within or near each gene locus. We exploited this endogenous variation to identify coexpression networks and downstream targets in mouse and human. Through a combined systems genetics approach, we provide new insight into the biological role of naturally occurring variants in GST genes. PMID:26829228

  10. The role of ERG20 gene (encoding yeast farnesyl diphosphate synthase) mutation in long dolichol formation. Molecular modeling of FPP synthase.

    PubMed

    Plochocka, D; Karst, F; Swiezewska, E; Szkopińska, A

    2000-08-01

    The yeast Saccharomyces cerevisiae strain LB332 bearing a mutation in the ERG20 gene encoding farnesyl diphosphate synthase (FPPS) synthesizes significantly longer dolichols than the wild type strain FL100 (14-31 and 14-19 isoprene units, respectively). The measurement of the short chain prenyl alcohols excreted into the medium shows that increased amounts of geraniol, dimethylallyl and isopentenyl alcohols but not farnesol are synthesized by the mutant strain. The wild type FPPS synthesizes farnesyl diphosphate (FPP) as the only product. The K197E substitution, as opposed to F112A/F113S in avian FPPS, does not change product specificity. Consequently, the possibility that mutated yeast FPPS synthesizes longer polyprenols is unlikely. This is supported by additional evidence such as in vitro analysis of the mutated FPPS products and molecular modeling. We suggest that formation of longer dolichols in vivo is the result of a change in the isopentenyl diphosphate/farnesyl diphosphate ratio caused by the erg20 mutation which in turn affects the activity of cis-prenyltransferase.

  11. Molecular cloning and expression of Hedychium coronarium farnesyl pyrophosphate synthase gene and its possible involvement in the biosynthesis of floral and wounding/herbivory induced leaf volatile sesquiterpenoids.

    PubMed

    Lan, Jian-bin; Yu, Rang-cai; Yu, Yun-yi; Fan, Yan-ping

    2013-04-15

    Farnesyl pyrophosphate synthase (FPPS EC 2.5.1.10) catalyzes the production of farnesyl pyrophosphate (FPP), which is a key precursor for many sesquiterpenoids such as floral scent and defense volatiles against herbivore attack. Here we report a new full-length cDNA encoding farnesyl diphosphate synthase from Hedychium coronarium. The open reading frame for full-length HcFPPS encodes a protein of 356 amino acids, which is 1068 nucleotides long with calculated molecular mass of 40.7 kDa. Phylogenetic tree analysis indicates that HcFPPS belongs to the plant FPPS super-family and has strong relationship with FPPS from Musa acuminata. Expression of the HcFPPS gene in Escherichia coli yielded FPPS activity. Tissue-specific and developmental analyses of the HcFPPS mRNA and corresponding volatile sesquiterpenoid levels in H. coronarium flowers revealed that the HcFPPS might play a regulatory role in floral volatile sesquiterpenoid biosynthesis. The emission of the FPP-derived volatile terpenoid correlates with strong expression of HcFPPS induced by mechanical wounding and Udaspes folus-damage in leaves, which suggests that HcFPPS may have an important ecological function in H. coronarium vegetative organ.

  12. Thermodynamic, dynamic and solvational properties of PDEδ binding to farnesylated cystein: a model study for uncovering the molecular mechanism of PDEδ interaction with prenylated proteins.

    PubMed

    Suladze, S; Ismail, S; Winter, R

    2014-01-30

    The protein PDEδ is an important solubilizing factor for several prenylated proteins including the Ras subfamily members. The binding occurs mainly through the farnesyl anchor of Ras proteins, which is recognized by a hydrophobic pocket of PDEδ. In this study, we carried out a detailed study of the thermodynamic and solvational properties of PDEδ binding to farnesyl-cystein, which serves as a model for PDEδ association to prenylated proteins. Using various biophysical approaches in conjunction with theoretical considerations, we show here that binding of the largely hydrophobic ligand surprisingly has enthalpy-driven signature, and the entropy change is largely controlled by the fine balance between the hydrational and conformational terms. Moreover, binding of PDEδ to farnesyl-cystein is accompanied by an increase in thermal stability, the release of about 150 water molecules from the interacting species, a decrease in solvent accessible surface area, and a marked decrease of the volume fluctuations and hence dynamics of the protein. Altogether, our results shed more light on the molecular mechanism of PDEδ interaction with prenylated Ras proteins, which is also prerequisite for an optimization of the structure-based molecular design of drugs against Ras related diseases and for understanding the multitude of biological functions of PDEδ.

  13. Isoenzymes of glutathione transferase in rat small intestine.

    PubMed Central

    Tahir, M K; Ozer, N; Mannervik, B

    1988-01-01

    The major glutathione transferases in the rat small-intestine cytosol were isolated and characterized. The enzymes active with 1-chloro-2,4-dinitrobenzene as second substrate were almost quantitatively recovered after affinity chromatography on immobilized S-hexylglutathione. The different basic forms of glutathione transferase, which account for 90% of the activity, were resolved by chromatofocusing. Fractions containing enzymes with lower isoelectric points were not further resolved. The isolated fractions were characterized by their elution position in chromatofocusing, apparent subunit Mr, reactions with specific antibodies, substrate specificities and inhibition characteristics. The major basic forms identified were glutathione transferases 1-1, 4-4 and 7-7. In addition, evidence for the presence of a variant form of subunit 1, as well as trace amounts of subunits 2 and 3, was obtained. A significant amount of transferase 8-8 in the fraction of acidic enzyme forms was demonstrated by immunoblot and Ouchterlony double-diffusion analysis. In the comparison of the occurrence of the different forms of glutathione transferase in liver, lung, kidney and small intestine, it was found that the small intestine is the richest source of glutathione transferase 7-7. Images Fig. 2. Fig. 3. Fig. 4. PMID:3140787

  14. Gamma-glutamyl transferase and cardiovascular disease

    PubMed Central

    Kastrati, Adnan

    2016-01-01

    Gamma-glutamyl transferase (GGT) is an enzyme located on the external surface of cellular membranes. GGT contributes in maintaining the physiological concentrations of cytoplasmic glutathione and cellular defense against oxidative stress via cleavage of extracellular glutathione and increased availability of amino acids for its intracellular synthesis. Increased GGT activity is a marker of antioxidant inadequacy and increased oxidative stress. Ample evidence suggests that elevated GGT activity is associated with increased risk of cardiovascular disease (CVD) such as coronary heart disease (CHD), stroke, arterial hypertension, heart failure, cardiac arrhythmias and all-cause and CVD-related mortality. The evidence is weaker for an association between elevated GGT activity and acute ischemic events and myocardial infarction. The risk for CVD or CVD-related mortality mediated by GGT may be explained by the close correlation of GGT with conventional CVD risk factors and various comorbidities, particularly non-alcoholic fatty liver disease, alcohol consumption, oxidative stress, metabolic syndrome, insulin resistance and systemic inflammation. The finding of GGT activity in atherosclerotic plaques and correlation of intra-plaque GGT activity with histological indexes of plaque instability may suggest a participation of GGT in the pathophysiology of CVD, particularly atherosclerosis. However, whether GGT has a direct role in the pathophysiology of CVD or it is an epiphenomenon of coexisting CVD risk factors or comorbidities remains unknown and Hill’s criteria of causality relationship between GGT and CVD are not fulfilled. The exploration whether GGT provides prognostic information on top of the information provided by known cardiovascular risk factors regarding the CVD or CVD-related outcome and exploration of molecular mechanisms of GGT involvement in the pathophysiology of CVD and eventual use of interventions to reduce circulating GGT activity remain a duty of

  15. Glutathione transferase isoenzymes from human prostate.

    PubMed Central

    Di Ilio, C; Aceto, A; Bucciarelli, T; Angelucci, S; Felaco, M; Grilli, A; Federici, G

    1990-01-01

    By using affinity-chromatography and isoelectric-focusing techniques, several forms of glutathione transferase (GSTs) were resolved from human prostate cytosol. All the three major classes of GST, i.e. Alpha, Mu and Pi, are present in human prostate. However, large inter-individual variation in the qualitative and quantitative expression of different isoenzymes resulted in the samples investigated. The most abundant group of prostate isoenzymes showed acid (pI 4.3-4.7) behaviour and were classified as Pi class GSTs on the basis of their immunological and structural properties. Immunohistochemical staining of Pi class GSTs was prevalently distributed in the epithelial cells surrounding the alveolar lumen. Class Mu GSTs are also expressed, although in small amounts and in a limited number of samples, by human prostate. The major cationic isoenzyme purified from prostate, GST-9.6; (pI 9.6; apparent subunit molecular mass of 28 kDa), appears to be different from the cationic GST alpha-epsilon forms isolated from human liver and kidney as evidenced by its structural, kinetical and immunological properties. This enzyme, which accounts for about 20-30% (on protein basis) of total amount of GSTs, is expressed by only 40% of samples. GST-9.6 has the ability to cross-react in immunoblotting analysis with antisera raised against rat liver GST 2-2, rather than with antisera raised against members of human Alpha, Mu and Pi class GSTs. Although prostate GST-9.6 shows close relationship with the human skin GST pI 9.9, it does not correspond to any other known human GST. Images Fig. 2. Fig. 3. Fig. 4. PMID:2241927

  16. Isoprenoid quantitation in human brain tissue: a validated HPLC-fluorescence detection method for endogenous farnesyl- (FPP) and geranylgeranylpyrophosphate (GGPP).

    PubMed

    Hooff, Gero P; Volmer, Dietrich A; Wood, W Gibson; Müller, Walter E; Eckert, Gunter P

    2008-10-01

    Farnesyl- and geranylgeranylpyrophosphate (FPP and GGPP) are isoprenoid intermediates in the mevalonate pathway. They play a crucial role in cell survival, growth and differentiation due to their attachment (isoprenylation) to small GTPases (Ras, Rho, etc.). Isoprenoid formation seems to be tightly regulated within the mevalonate pathway and its perturbation has been linked to certain diseases (e.g., cancer, Alzheimer's disease), but tissue levels are unknown. It is therefore of the utmost importance to quantify these isoprenoids in diseased tissue or in tissue after drug administration. The current work describes an isolation procedure utilizing a combination of Extrelut(R) liquid/liquid and reversed-phase solid-phase extraction (SPE) for homogenized human frontal cortex tissue. In addition, after a careful validation of an HPLC-fluorescence method, this assay allowed the determination of nanomolar concentrations of endogenous FPP and GGPP levels (4.5 and 10.6 ng/mg protein, respectively) in human brain tissue. The method is selective, precise (<15% RSD), accurate (<15% relative error) and sensitive over a linear range of 10-400 ng/mL for FPP and 50-1000 ng/mL for GGPP according to the current FDA criteria for bioanalytical method validation. Overall, this new method introduces the ability to simultaneously quantify FPP and GGPP in human brain tissue, and is potentially applicable to several other tissues and species.

  17. Isoprenoid quantitation in human brain tissue. A validated HPLC-fluorescence detection method for endogenous farnesyl- (FPP) and geranylgeranylpyrophosphate (GGPP)

    PubMed Central

    2010-01-01

    Farnesyl- and geranylgeranylpyrophosphate (FPP and GGPP) are isoprenoid intermediates in the mevalonate pathway. They play a crucial role in cell survival, growth and differentiation by their attachment (isoprenylation) to small GTPases (Ras, Rho etc.). Isoprenoid formation seems to be tightly regulated within the mevalonate pathway and its perturbation has been linked to certain diseases (e.g., cancer, Alzheimer's disease) but tissue levels are unknown. It is therefore of utmost importance to quantify these isoprenoids in diseased tissue or in tissue after drug administration. The current work describes an isolation procedure utilizing a combination of Extrelut® liquid/liquid and reversed-phase solid-phase extraction (SPE) for homogenized human frontal cortex tissue. In addition, after a careful validation of an HPLC-fluorescence method, this assay allowed determination of nanomolar concentrations of endogenous FPP and GGPP levels (4.5 and 10.6 ng/mg protein, respectively) in human brain tissue. The method is selective, precise (< 15% RSD), accurate (< 15% relative error) and sensitive over a linear range of 10 – 400 ng/mL for FPP and 50 – 1000 ng/mL for GGPP according to the current FDA criteria for bioanalytical method validation. Overall, this new method introduces the ability to simultaneously quantify FPP and GGPP in human brain tissue with the prospect for application to several other tissues and species. PMID:18690423

  18. Enhanced triterpene accumulation in Panax ginseng hairy roots overexpressing mevalonate-5-pyrophosphate decarboxylase and farnesyl pyrophosphate synthase.

    PubMed

    Kim, Yong-Kyoung; Kim, Yeon Bok; Uddin, Md Romij; Lee, Sanghyun; Kim, Soo-Un; Park, Sang Un

    2014-10-17

    To elucidate the function of mevalonate-5-pyrophosphate decarboxylase (MVD) and farnesyl pyrophosphate synthase (FPS) in triterpene biosynthesis, the genes governing the expression of these enzymes were transformed into Panax ginseng hairy roots. All the transgenic lines showed higher expression levels of PgMVD and PgFPS than that by the wild-type control. Among the hairy root lines transformed with PgMVD, M18 showed the highest level of transcription compared to the control (14.5-fold higher). Transcriptions of F11 and F20 transformed with PgFPS showed 11.1-fold higher level compared with control. In triterpene analysis, M25 of PgMVD produced 4.4-fold higher stigmasterol content (138.95 μg/100 mg, dry weight [DW]) than that by the control; F17 of PgFPS showed the highest total ginsenoside (36.42 mg/g DW) content, which was 2.4-fold higher compared with control. Our results indicate that metabolic engineering in P. ginseng was successfully achieved through Agrobacterium rhizogenes-mediated transformation and that the accumulation of phytosterols and ginsenosides was enhanced by introducing the PgMVD and PgFPS genes into the hairy roots of the plant. Our results suggest that PgMVD and PgFPS play an important role in the triterpene biosynthesis of P. ginseng.

  19. Binding of nitrogen-containing bisphosphonates (N-BPs) to the Trypanosoma cruzi farnesyl diphosphate synthase homodimer

    SciTech Connect

    Huang, Chuan-Hsiang; Gabelli, Sandra B.; Oldfield, Eric; Amzel, L. Mario

    2010-11-15

    Bisphosphonates (BPs) are a class of compounds that have been used extensively in the treatment of osteoporosis and malignancy-related hypercalcemia. Some of these compounds act through inhibition of farnesyl diphosphate synthase (FPPS), a key enzyme in the synthesis of isoprenoids. Recently, nitrogen-containing bisphosphonates (N-BPs) used in bone resorption therapy have been shown to be active against Trypanosoma cruzi, the parasite that causes American trypanosomiasis (Chagas disease), suggesting that they may be used as anti-trypanosomal agents. The crystal structures of TcFPPS in complex with substrate (isopentenyl diphosphate, IPP) and five N-BP inhibitors show that the C-1 hydroxyl and the nitrogen-containing groups of the inhibitors alter the binding of IPP and the conformation of two TcFPPS residues, Tyr94 and Gln167. Isothermal titration calorimetry experiments suggest that binding of the first N-BPs to the homodimeric TcFPPS changes the binding properties of the second site. This mechanism of binding of N-BPs to TcFPPS is different to that reported for the binding of the same compounds to human FPPS.

  20. Cloning and functional analysis of farnesyl diphosphate synthase (FPPS) gene from Mylabris cichorii Cloning, functional analysis of McFPPS.

    PubMed

    Zha, Shenfang; Yin, Youping; Wang, Yu; Huang, Yi; Li, Yan; Wang, Zhongkang

    2016-03-14

    Cantharidin, a defensive terpene compound synthesized by the meloid beetle (Coleoptera, Meloidae), is an important anti-cancer agent. However, there has been little study done on how this compound synthesized by the beetle. In this paper, a farnesyl-diphosphate synthase gene, designated McFPPS, was isolated from Mylabris cichorii by RT-PCR based on conserved domains in other organisms. Multiple alignment analysis showed that the deduced amino acids shared >70% homology with FPPSs from other species and contained typically seven conservative regions. Expression profile analysis revealed that McFPPS was expressed throughout the tested growth stages of M. cichorii adults; whereas the transcripts accumulated to the highest level at 20 d male adults while the highest expression level appeared at 15 d females. Tissue expression pattern analysis showed McFPPS was expressed constitutively in all tested tissues and a relatively higher expression level in the alimentary canal of males, but no significant tissue difference in the females. For the first time, a RNA interference strategy was employed to induce a greater suppression of McFPPS mRNA, and thus, a sharp decrease in the expression levels of downstream genes and the concentration of product. All these results indicated McFPPS may be directly involved or play an essential role in the biosynthesis of cantharidin. This article is protected by copyright. All rights reserved.

  1. Biosynthesis of anthecotuloide, an irregular sesquiterpene lactone from Anthemis cotula L. (Asteraceae) via a non-farnesyl diphosphate route.

    PubMed

    van Klink, John; Becker, Hans; Andersson, Susannah; Boland, Wilhelm

    2003-05-07

    Retrobiosynthetic analysis of the allergenic sesquiterpene lactone, anthecotuloide, suggested that this natural product could be formed either by head to head condensation of geranyl diphosphate with dimethylallyl diphosphate, or from farnesyl diphosphate (FPP), the accepted regular sesquiterpene precursor via the rearrangement of a germacranolide precursor. Isotopic labelling of anthecotuloide has now been achieved by feeding [1-(13)C]-glucose, [U-13C6]-glucose and [6,6-(2)H2]-glucose to aseptically grown plantlets of Anthemis cotula(family Asteraceae). Analysis of labelling patterns and absolute 13C abundances using quantitative 13C NMR spectroscopy showed that the isoprene building blocks of this sesquiterpene are formed exclusively via the MEP terpene biosynthetic pathway. This was supported by results from an experiment using [U-13C6]-glucose. A deuterium labelling experiment using [6,6-(2)H2]-glucose supported the original proposal and showed that anthecotuloide is formed from a non FPP precursor. Isotope ratio mass spectrometry suggested that there were two pathways for sesquiterpene biosynthesis in A. cotula.

  2. Oral Cancer

    MedlinePlus

    Oral Cancer Basic description Cancer can affect any part of the oral cavity, including the lips, tongue, mouth, and throat. There are 2 kinds of oral cancer: oral cavity cancer and oropharyngeal cancer. The most ...

  3. Clinical Trial of the Protein Farnesylation Inhibitors Lonafarnib, Pravastatin, and Zoledronic Acid in Children With Hutchinson-Gilford Progeria Syndrome.

    PubMed

    Gordon, Leslie B; Kleinman, Monica E; Massaro, Joe; D'Agostino, Ralph B; Shappell, Heather; Gerhard-Herman, Marie; Smoot, Leslie B; Gordon, Catherine M; Cleveland, Robert H; Nazarian, Ara; Snyder, Brian D; Ullrich, Nicole J; Silvera, V Michelle; Liang, Marilyn G; Quinn, Nicolle; Miller, David T; Huh, Susanna Y; Dowton, Anne A; Littlefield, Kelly; Greer, Maya M; Kieran, Mark W

    2016-07-12

    Hutchinson-Gilford progeria syndrome is an extremely rare, fatal, segmental premature aging syndrome caused by a mutation in LMNA yielding the farnesylated aberrant protein progerin. Without progerin-specific treatment, death occurs at an average age of 14.6 years from an accelerated atherosclerosis. A previous single-arm clinical trial demonstrated that the protein farnesyltransferase inhibitor lonafarnib ameliorates some aspects of cardiovascular and bone disease. This present trial sought to further improve disease by additionally inhibiting progerin prenylation. Thirty-seven participants with Hutchinson-Gilford progeria syndrome received pravastatin, zoledronic acid, and lonafarnib. This combination therapy was evaluated, in addition to descriptive comparisons with the prior lonafarnib monotherapy trial. No participants withdrew because of side effects. Primary outcome success was predefined by improved per-patient rate of weight gain or carotid artery echodensity; 71.0% of participants succeeded (P<0.0001). Key cardiovascular and skeletal secondary variables were predefined. Secondary improvements included increased areal (P=0.001) and volumetric (P<0.001-0.006) bone mineral density and 1.5- to 1.8-fold increases in radial bone structure (P<0.001). Median carotid artery wall echodensity and carotid-femoral pulse wave velocity demonstrated no significant changes. Percentages of participants with carotid (5% to 50%; P=0.001) and femoral (0% to 12%; P=0.13) artery plaques and extraskeletal calcifications (34.4% to 65.6%; P=0.006) increased. Other than increased bone mineral density, no improvement rates exceeded those of the prior lonafarnib monotherapy treatment trial. Comparisons with lonafarnib monotherapy treatment reveal additional bone mineral density benefit but likely no added cardiovascular benefit with the addition of pravastatin and zoledronic acid. URL: http://www.clinicaltrials.gov. Unique identifiers: NCT00879034 and NCT00916747. © 2016 American

  4. Sesquiterpene synthases Cop4 and Cop6 from Coprinus cinereus: catalytic promiscuity and cyclization of farnesyl pyrophosphate geometric isomers.

    PubMed

    Lopez-Gallego, Fernando; Agger, Sean A; Abate-Pella, Daniel; Distefano, Mark D; Schmidt-Dannert, Claudia

    2010-05-17

    Sesquiterpene synthases catalyze with different catalytic fidelity the cyclization of farnesyl pyrophosphate (FPP) into hundreds of known compounds with diverse structures and stereochemistries. Two sesquiterpene synthases, Cop4 and Cop6, were previously isolated from Coprinus cinereus as part of a fungal genome survey. This study investigates the reaction mechanism and catalytic fidelity of the two enzymes. Cyclization of all-trans-FPP ((E,E)-FPP) was compared to the cyclization of the cis-trans isomer of FPP ((Z,E)-FPP) as a surrogate for the secondary cisoid neryl cation intermediate generated by sesquiterpene synthases, which are capable of isomerizing the C2--C3 pi bond of all-trans-FPP. Cop6 is a "high-fidelity" alpha-cuprenene synthase that retains its fidelity under various conditions tested. Cop4 is a catalytically promiscuous enzyme that cyclizes (E,E)-FPP into multiple products, including (-)-germacrene D and cubebol. Changing the pH of the reaction drastically alters the fidelity of Cop4 and makes it a highly selective enzyme. Cyclization of (Z,E)-FPP by Cop4 and Cop6 yields products that are very different from those obtained with (E,E)-FPP. Conversion of (E,E)-FPP proceeds via a (6R)-beta-bisabolyl carbocation in the case of Cop6 and an (E,E)-germacradienyl carbocation in the case of Cop4. However, (Z,E)-FPP is cyclized via a (6S)-beta-bisabolene carbocation by both enzymes. Structural modeling suggests that differences in the active site and the loop that covers the active site of the two enzymes might explain their different catalytic fidelities.

  5. Farnesyl pyrophosphate is an endogenous antagonist to ADP-stimulated P2Y12 receptor-mediated platelet aggregation

    PubMed Central

    Högberg, Carl; Gidlöf, Olof; Deflorian, Francesca; Jacobson, Kenneth A.; Abdelrahman, Aliaa; Miüller, Christa E.; Olde, Björn; Erlinge, David

    2012-01-01

    Summary Farnesyl pyrophosphate (FPP) is an intermediate in cholesterol biosynthesis, and it has also been reported to activate platelet LPA (lysophosphatidic acid) receptors. The aim of this study was to investigate the role of extracellular FPP in platelet aggregation. Human platelets were studied with light transmission aggregometry, flow cytometry and [35S]GTPγS binding assays. As shown previously, FPP could potentiate LPA-stimulated shape change. Surprisingly, FPP also acted as a selective insurmountable antagonist to ADP-induced platelet aggregation. FPP inhibited ADP-induced expression of P-selectin and the activated glycoprotein (Gp)llb/llla receptor. FPP blocked ADP-induced inhibition of cAMP accumulation and [35S]GTPγS binding in platelets. In Chinese hamster ovary cells expressing the P2Y12 receptor, FPP caused a right-ward shift of the [35S]GTPγS binding curve. In Sf9 insect cells expressing the human P2Y12 receptor, FPP showed a concentration-dependent, although incomplete inhibition of [3H]PSB-0413 binding. Docking of FPP in a P2Y12 receptor model revealed molecular similarities with ADP and a good fit into the binding pocket for ADP. In conclusion, FPP is an insurmountable antagonist of ADP-induced platelet aggregation mediated by the P2Y12 receptor. It could be an endogenous antithrombotic factor modulating the strong platelet aggregatory effects of ADP in a manner similar to the use of clopidogrel, prasugrel or ticagrelor in the treatment of ischaemic heart disease. PMID:22628078

  6. Farnesyl pyrophosphate is an endogenous antagonist to ADP-stimulated P2Y₁₂ receptor-mediated platelet aggregation.

    PubMed

    Högberg, Carl; Gidlöf, Olof; Deflorian, Francesca; Jacobson, Kenneth A; Abdelrahman, Aliaa; Müller, Christa E; Olde, Björn; Erlinge, David

    2012-07-01

    Farnesyl pyrophosphate (FPP) is an intermediate in cholesterol biosynthesis, and it has also been reported to activate platelet LPA (lysophosphatidic acid) receptors. The aim of this study was to investigate the role of extracellular FPP in platelet aggregation. Human platelets were studied with light transmission aggregometry, flow cytometry and [³⁵S]GTPγS binding assays. As shown previously, FPP could potentiate LPA-stimulated shape change. Surprisingly, FPP also acted as a selective insurmountable antagonist to ADP-induced platelet aggregation. FPP inhibited ADP-induced expression of P-selectin and the activated glycoprotein (Gp)IIb/IIIa receptor. FPP blocked ADP-induced inhibition of cAMP accumulation and [³⁵S]GTPγS binding in platelets. In Chinese hamster ovary cells expressing the P2Y₁₂ receptor, FPP caused a rightward shift of the [³⁵S]GTPγS binding curve. In Sf9 insect cells expressing the human P2Y₁₂ receptor, FPP showed a concentration-dependent, although incomplete inhibition of [³H]PSB-0413 binding. Docking of FPP in a P2Y₁₂ receptor model revealed molecular similarities with ADP and a good fit into the binding pocket for ADP. In conclusion, FPP is an insurmountable antagonist of ADP-induced platelet aggregation mediated by the P2Y₁₂ receptor. It could be an endogenous antithrombotic factor modulating the strong platelet aggregatory effects of ADP in a manner similar to the use of clopidogrel, prasugrel or ticagrelor in the treatment of ischaemic heart disease.

  7. Preclinical evidence for nitrogen-containing bisphosphonate inhibition of farnesyl diphosphate (FPP) synthase in the kidney: implications for renal safety.

    PubMed

    Lühe, Anke; Künkele, Klaus-Peter; Haiker, Monika; Schad, Karen; Zihlmann, Christine; Bauss, Frieder; Suter, Laura; Pfister, Thomas

    2008-06-01

    Bisphosphonates are potent inhibitors of osteoclast-mediated bone resorption and play an important role in the treatment of osteoporosis, metastatic bone disease, and Paget disease. However, nephrotoxicity has been reported with some bisphosphonates. Nitrogen-containing bisphosphonates directly inhibit farnesyl diphosphate (FPP) synthase activity (mevalonate pathway) and reduce protein prenylation leading to osteoclast cell death. The aim here was to elucidate if this inhibition also occurs in kidney cells and may directly account for nephrotoxicity. In an exploratory study in rats receiving zoledronate or ibandronate an approximate 2-fold increase in FPP synthase mRNA levels was observed in the kidney. The involvement of the mevalonate pathway was confirmed in subsequent in vitro studies with zoledronate, ibandronate, and pamidronate, using the non-nitrogen containing bisphosphonate clodronate as a comparator. In vitro changes in FPP synthase mRNA expression, enzyme activity, and levels of prenylated proteins were assessed. Using two cell lines (a rat normal kidney cell line, NRK-52E, and a human kidney proximal tubule cell line, HK-2), ibandronate and zoledronate were identified as most cytotoxic (EC50: 23/>1000 microM and 16/82 microM, respectively) and as the most potent inhibitors of FPP synthase (IC50; 1.6/7.4 microM and 0.5/0.7 microM, respectively). In both cell lines, inhibition of FPP synthase activity occurred prior to a decrease in levels of prenylated proteins followed by cytotoxicity. This further supports that the mechanism responsible for osteoclast inhibition (therapeutic effect) might also underlie the mechanism of nephrotoxicity.

  8. Sesquiterpene synthases Cop4 and Cop6 from Coprinus cinereus: Catalytic promiscuity and cyclization of farnesyl pyrophosphate geometrical isomers

    PubMed Central

    Lopez-Gallego, Fernando; Agger, Sean A.; Pella, Daniel A.; Distefano, Mark D.; Schmidt-Dannert, Claudia

    2010-01-01

    Sesquiterpene synthases catalyze with different catalytic fidelity the cyclization of farnesyl pyrophosphate (FPP) into hundreds of known compounds with diverse structures and stereochemistries. Two sesquiterpene synthases, Cop4 and Cop6, were previously isolated from Coprinus cinereus as part of a fungal genome survey. This study investigates the reaction mechanism and catalytic fidelity of the two enzymes. Cyclization of all-trans-FPP ((E,E)-FPP) was compared to the cyclization of the cis-trans isomer of FPP ((Z,E)-FPP) as a surrogate for the secondary cisoid neryl cation intermediate generated by sesquiterpene synthases capable of isomerizing the C2-C3 π bond of all-trans-FPP. Cop6 is a “high-fidelity” α-cuprenene synthase that retains its fidelity under various conditions tested. Cop4 is a catalytically promiscuous enzyme that cyclizes (E,E)-FPP into multiple products, including (−)-germacrene D and cubebol. Changing the pH of the reaction drastically alters the fidelity of Cop4 and makes it a highly selective enzyme. Cyclization of (Z,E)-FPP by Cop4 and Cop6 yields products that are very different from those obtained with (E,E)-FPP. Conversion of (E,E)-FPP proceeds via a (6R)-β-bisabolyl carbocation in the case of Cop6 and an (E,E)-germacradienyl carbocation in the case of Cop4. However, (Z,E)-FPP is cyclized via a (6S)-β-bisabolene carbocation by both enzymes. Structural modeling suggests that differences in the active site and the loop that covers the active site of the two enzymes may explain their different catalytic fidelities. PMID:20419721

  9. Very high-density lipoprotein and vitellin as carriers of novel biliverdins IXα with a farnesyl side-chain presumably derived from heme A in Spodoptera littoralis.

    PubMed

    Kayser, Hartmut; Nimtz, Manfred; Ringler, Philippe; Müller, Shirley A

    2016-01-01

    Bilins in complex with specific proteins play key roles in many forms of life. Biliproteins have also been isolated from insects; however, structural details are rare and possible functions largely unknown. Recently, we identified a high-molecular weight biliprotein from a moth, Cerura vinula, as an arylphorin-type hexameric storage protein linked to a novel farnesyl biliverdin IXα; its unusual structure suggests formation by cleavage of mitochondrial heme A. In the present study of another moth, Spodoptera littoralis, we isolated two different biliproteins. These proteins were identified as a very high-density lipoprotein (VHDL) and as vitellin, respectively, by mass spectrometric sequencing. Both proteins are associated with three different farnesyl biliverdins IXα: the one bilin isolated from C. vinula and two new structurally closely related bilins, supposed to be intermediates of heme A degradation. The different bilin composition of the two biliproteins suggests that the presumed oxidations at the farnesyl side-chain take place mainly during egg development. The egg bilins are supposedly transferred from hemolymph VHDL to vitellin in the female. Both biliproteins show strong induced circular dichroism activity compatible with a predominance of the M-conformation of the bilins. This conformation is opposite to that of the arylphorin-type biliprotein from C. vinula. Electron microscopy of the VHDL-type biliprotein from S. littoralis provided a preliminary view of its structure as a homodimer and confirmed the biochemically determined molecular mass of ∼350 kDa. Further, images of S. littoralis hexamerins revealed a 2 × 3 construction identical to that known from the hexamerin from C. vinula.

  10. Homogentisate solanesyl transferase (HST) cDNA’s in maize

    USDA-ARS?s Scientific Manuscript database

    Maize white seedling 3 (w3) has served as a model albino-seedling mutant since its discovery in 1923. We show that the w3 phenotype is caused by disruptions in homogentisate solanesyl transferase (HST), an enzyme that catalyzes the committed step in plastoquinone-9 (PQ9) biosynthesis. This reaction ...

  11. GLUTATHIONE S-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE

    EPA Science Inventory

    GLUTATHIONE s-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE. M K Ross1 and R A Pegram2. 1Curriculum in Toxicology, University of North Carolina at Chapel Hill; 2Experimental Toxicology Division, NHEERL/ORD, United States Environmental Protection Agency, Research Triangl...

  12. Histamine N-methyl transferase: inhibition by drugs.

    PubMed Central

    Pacifici, G M; Donatelli, P; Giuliani, L

    1992-01-01

    1. Histamine N-methyl transferase activity was measured in samples of human liver, brain, kidney, lung and intestinal mucosa. The mean (+/- s.d.) rate (nmol min-1 mg-1 protein) of histamine N-methylation was 1.78 +/- 0.59 (liver, n = 60), 1.15 +/- 0.38 (renal cortex, n = 8), 0.79 +/- 0.14 (renal medulla, n = 8), 0.35 +/- 0.08 (lung, n = 20), 0.47 +/- 0.18 (human intestine, n = 30) and 0.29 +/- 0.14 (brain, n = 13). 2. Inhibition of histamine N-methyl transferase by 15 drugs was investigated in human liver. The IC50 for the various drugs ranged over three orders of magnitude; chloroquine was the most potent inhibitor. 3. The average IC50 values for chloroquine were 12.6, 22.0, 19.0, 21.6 microM in liver, renal cortex, brain and colon, respectively. These values are lower than the Michaelis-Menten constant for histamine N-methyltransferase in liver (43.8 microM) and kidney (45.5 microM). Chloroquine carried a mixed non-competitive inhibition of hepatic histamine N-methyl transferase. Some side-effects of chloroquine may be explained by inhibition of histamine N-methyl transferase. PMID:1457266

  13. Late onset ornithine carbamoyl transferase deficiency in males.

    PubMed Central

    Drogari, E; Leonard, J V

    1988-01-01

    Six boys with ornithine carbamoyl transferase deficiency presenting in infancy or later childhood are described. There was wide variation in both the time of presentation and the symptoms, which may initially suggest a neurological, behavioural, or gastroenterological problem. Two patients died, as did two male siblings who were probably affected, but with early recognition of the hyperammonaemia the outlook is good. PMID:3202644

  14. GLUTATHIONE S-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE

    EPA Science Inventory

    GLUTATHIONE s-TRANSFERASE-MEDIATED METABOLISM OF BROMODICHLOROMETHANE. M K Ross1 and R A Pegram2. 1Curriculum in Toxicology, University of North Carolina at Chapel Hill; 2Experimental Toxicology Division, NHEERL/ORD, United States Environmental Protection Agency, Research Triangl...

  15. 21 CFR 862.1535 - Ornithine carbamyl transferase test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ornithine carbamyl transferase test system. 862.1535 Section 862.1535 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... and treatment of liver diseases, such as infectious hepatitis, acute cholecystitis (inflammation of...

  16. Rational design of an organometallic glutathione transferase inhibitor

    SciTech Connect

    Ang, W.H.; Parker, L.J.; De Luca, A.; Juillerat-Jeanneret, L.; Morton, C.J.; LoBello, M.; Parker, M.W.; Dyson, P.J.

    2010-08-17

    A hybrid organic-inorganic (organometallic) inhibitor was designed to target glutathione transferases. The metal center is used to direct protein binding, while the organic moiety acts as the active-site inhibitor. The mechanism of inhibition was studied using a range of biophysical and biochemical methods.

  17. Identification of a novel glutathione transferase in human skin homologous with class alpha glutathione transferase 2-2 in the rat.

    PubMed

    Del Boccio, G; Di Ilio, C; Alin, P; Jörnvall, H; Mannervik, B

    1987-05-15

    Six forms of glutathione transferase with pI values of 4.6, 5.9, 6.8, 7.1, 8.5 and 9.9 have been isolated from the cytosol fraction of normal skin from three human subjects. The three most abundant enzymes were an acidic Class Pi transferase (pI 4.6; apparent subunit Mr 23,000), a basic Class Alpha transferase (pI 8.5; apparent subunit Mr 24,000) and an even more basic glutathione transferase of Class Alpha (pI 9.9; apparent subunit Mr 26,500). The last enzyme, which was previously unknown, accounts for 10-20% of the glutathione transferase in human skin. The novel transferase showed greater similarities with rat glutathione transferase 2-2, another Class Alpha enzyme, than with any other known transferase irrespective of species. The most striking similarities included reactions with antibodies, amino acid compositions and identical N-terminal amino acid sequences (16 residues). The close relationship between the human most basic and the rat glutathione transferase 2-2 supports the classification of the transferases previously proposed and indicates that the similarities between enzymes isolated from different species are more extensive than had been assumed previously.

  18. Identification of a novel glutathione transferase in human skin homologous with class alpha glutathione transferase 2-2 in the rat.

    PubMed Central

    Del Boccio, G; Di Ilio, C; Alin, P; Jörnvall, H; Mannervik, B

    1987-01-01

    Six forms of glutathione transferase with pI values of 4.6, 5.9, 6.8, 7.1, 8.5 and 9.9 have been isolated from the cytosol fraction of normal skin from three human subjects. The three most abundant enzymes were an acidic Class Pi transferase (pI 4.6; apparent subunit Mr 23,000), a basic Class Alpha transferase (pI 8.5; apparent subunit Mr 24,000) and an even more basic glutathione transferase of Class Alpha (pI 9.9; apparent subunit Mr 26,500). The last enzyme, which was previously unknown, accounts for 10-20% of the glutathione transferase in human skin. The novel transferase showed greater similarities with rat glutathione transferase 2-2, another Class Alpha enzyme, than with any other known transferase irrespective of species. The most striking similarities included reactions with antibodies, amino acid compositions and identical N-terminal amino acid sequences (16 residues). The close relationship between the human most basic and the rat glutathione transferase 2-2 supports the classification of the transferases previously proposed and indicates that the similarities between enzymes isolated from different species are more extensive than had been assumed previously. Images Fig. 2. Fig. 3. PMID:3117035

  19. Unusual N-Prenylation in Diazepinomicin Biosynthesis: The Farnesylation of a Benzodiazepine Substrate Is Catalyzed by a New Member of the ABBA Prenyltransferase Superfamily

    PubMed Central

    Bonitz, Tobias; Zubeil, Florian; Grond, Stephanie; Heide, Lutz

    2013-01-01

    The bacterium Micromonospora sp. RV115, isolated from a marine sponge, produces the unusual metabolite diazepinomicin, a prenylated benzodiazepine derivative. We have cloned the prenyltransferase gene dzmP from this organism, expressed it in Escherichia coli, and the resulting His8-tagged protein was purified and investigated biochemically. It was found to catalyze the farnesylation of the amide nitrogen of dibenzodiazepinone. DzmP belongs to the ABBA prenyltransferases and is the first member of this superfamily which utilizes farnesyl diphosphate as genuine substrate. All previously discovered members utilize either dimethylallyl diphosphate (C5) or geranyl diphosphate (C10). Another putative diazepinomicin biosynthetic gene cluster was identified in the genome of Streptomyces griseoflavus Tü4000, suggesting that the formation of diazepinomicin is not restricted to the genus Micromonospora. The gene cluster contains a gene ssrg_00986 with 61.4% identity (amino acid level) to dzmP. The gene was expressed in E. coli, and the purified protein showed similar catalytic properties as DzmP. Both enzymes also accepted other phenolic or phenazine substrates. ABBA prenyltransferases are useful tools for chemoenzymatic synthesis, due to their nature as soluble, stable biocatalysts. The discovery of DzmP and Ssrg_00986 extends the isoprenoid substrate range of this superfamily. The observed prenylation of an amide nitrogen is an unusual biochemical reaction. PMID:24376894

  20. Phosphorylation and inhibition of. gamma. -glutamyl transferase activity by cAMP-dependent protein kinase

    SciTech Connect

    Kolesnichenko, L.S.; Chernov, N.N.

    1986-10-20

    It was shown that preparations of bovine kidney ..gamma..-glutamyl transferase of differing degrees of purity are phosphorylated by cAMP-dependent protein kinase. This is accompanied by a decrease in both the transferase and hydrolase activities of the enzyme. Consequently, ..gamma..-glutamyl transferase may serve as the substrate and target of the regulation of cAMP-dependent protein kinase.

  1. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Galactose-1-phosphate uridyl transferase test... Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a) Identification. A galactose-1-phosphate uridyl transferase test system is a device intended to measure the activity...

  2. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Galactose-1-phosphate uridyl transferase test... Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a) Identification. A galactose-1-phosphate uridyl transferase test system is a device intended to measure the activity...

  3. Oral Cancer

    MedlinePlus

    Oral cancer can form in any part of the mouth. Most oral cancers begin in the flat cells that cover the ... your mouth, tongue, and lips. Anyone can get oral cancer, but the risk is higher if you are ...

  4. Oral myiasis.

    PubMed

    Saravanan, Thalaimalai; Mohan, Mathan A; Thinakaran, Meera; Ahammed, Saneem

    2015-01-01

    Myiasis is a pathologic condition in humans occurring because of parasitic infestation. Parasites causing myiasis belong to the order Diptera. Oral myiasis is seen secondary to oral wounds, suppurative lesions, and extraction wounds, especially in individuals with neurological deficit. In such cases, neglected oral hygiene and halitosis attracts the flies to lay eggs in oral wounds resulting in oral myiasis. We present a case of oral myiasis in 40-year-old male patient with mental disability and history of epilepsy.

  5. Oral Myiasis

    PubMed Central

    Saravanan, Thalaimalai; Mohan, Mathan A; Thinakaran, Meera; Ahammed, Saneem

    2015-01-01

    Myiasis is a pathologic condition in humans occurring because of parasitic infestation. Parasites causing myiasis belong to the order Diptera. Oral myiasis is seen secondary to oral wounds, suppurative lesions, and extraction wounds, especially in individuals with neurological deficit. In such cases, neglected oral hygiene and halitosis attracts the flies to lay eggs in oral wounds resulting in oral myiasis. We present a case of oral myiasis in 40-year-old male patient with mental disability and history of epilepsy. PMID:25709196

  6. The trans-stilbene oxide-active glutathione transferase in human mononuclear leucocytes is identical with the hepatic glutathione transferase mu.

    PubMed Central

    Seidegård, J; Guthenberg, C; Pero, R W; Mannervik, B

    1987-01-01

    A glutathione transferase from human mononuclear leucocytes with high activity towards trans-stilbene oxide (GT-tSBO) was purified. GT-tSBO is expressed in only about 50% of the individuals studied. As judged from activity measurements, immunological studies and the fact that only those individuals who express glutathione transferase mu have high activity towards trans-stilbene oxide, it is concluded that the hepatic transferase mu is identical with the glutathione transferase (GT-tSBO) in mononuclear leucocytes. PMID:3689332

  7. Evaluation of glutathione S-transferase activity in human buccal epithelial dysplasias and squamous cell carcinomas.

    PubMed

    Chen, Y K; Lin, L M

    1997-06-01

    Glutathione S-transferase (GST) activity and amount of GST alpha, mu and pi isoforms were measured in 40 patients with histopathologically confirmed oral epithelial dysplasia (OED) and squamous cell carcinoma of buccal mucosa. The results were compared with those of normal mucosa in an equal number of age- and sex-matched healthy controls. Mean total GST activities were significantly elevated from normal buccal mucosa for mild OED, moderate OED, severe OED and squamous cell carcinoma. GST activity of value approximating 100 nmol/min/mg distinguished between normal and dysplasia, and of value about 400 nmol/min/mg delineated between dysplasia and squamous cell carcinoma were observed. GST pi was the predominant class in both the diseased and normal buccal mucosa examined. This class pi GST was present at an intracellular concentration, which was significantly higher in diseased buccal mucosa than in normal buccal mucosa. These results indicated that pi class GST was the major form of this enzyme in the cytosolic fraction of oral mucosa. The severity of OED related to squamous cell carcinoma development seemed to increase concomitantly with an increase in the level of this enzyme. Further studies will validate the role of GST pi estimation in predicting the potential malignancy of OED.

  8. Glutathione-S-transferase activity in malarial parasites.

    PubMed

    Srivastava, P; Puri, S K; Kamboj, K K; Pandey, V C

    1999-04-01

    Glutathione-S-transferase (GST) activity has been detected in rodent (Plasmodium berghei, P. yoelii), simian (P. knowlesi) and human (P. falciparum) malarial parasites, and in different intraerythrocytic stages of P. knowlesi (schizont > ring > trophozoite). In chloroquine-resistant strains of rodent and human malarial parasites GST activity significantly increases compared to sensitive strains. Further, the increase in enzyme activity is directly related to drug pressure of resistant P. berghei. Complete inhibition of chloroquine-sensitive and resistant P. berghei glutathione-S-transferase activities was observed at 2.5 and 5. micrometer concentration of hemin, respectively. An inverse relationship was found between the heme level and enzyme activity of chloroquine-resistant and sensitive P. berghei. Chloroquine, artemisinin, and primaquine noticeably inhibited GST activity in P. knowlesi.

  9. Bacterial transferase MraY inhibitors: synthesis and biological evaluation.

    PubMed

    Lecerclé, Delphine; Clouet, Anthony; Al-Dabbagh, Bayan; Crouvoisier, Muriel; Bouhss, Ahmed; Gravier-Pelletier, Christine; Le Merrer, Yves

    2010-06-15

    New inhibitors of the bacterial transferase MraY are described. Their structure is based on an aminoribosyl-O-uridine like scaffold, readily obtained in two key steps. The amino group can be coupled with proline or guanylated. Alternatively, these amino, prolinyl or guanidinyl groups can be introduced through a triazole linker. Biological evaluation of these compounds on MraY from Bacillus subtilis revealed interesting inhibitory activity for both amino compounds. Copyright 2010. Published by Elsevier Ltd.

  10. [Glutathione S-transferase of alpha class from pike liver].

    PubMed

    Borvinskaia, E V; Smirnov, L P; Nemova, N N

    2013-01-01

    In this study, glutathione S-transferase (GST) was isolated from the liver of pike Esox lucius, which was homogenous according to SDS-PAGE and isoelectrofocusing. It is a homodimer with subunits mass 25235.36 Da (according to HPLC-MS/MS) and pI about 6.4. Substrate specificity, thermostability, some kinetic characteristics and optimum pH were determined. The enzyme was identified as Alpha class GST.

  11. Synthesis, chiral high performance liquid chromatographic resolution and enantiospecific activity of a potent new geranylgeranyl transferase inhibitor, 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid.

    PubMed

    McKenna, Charles E; Kashemirov, Boris A; Błazewska, Katarzyna M; Mallard-Favier, Isabelle; Stewart, Charlotte A; Rojas, Javier; Lundy, Mark W; Ebetino, Frank H; Baron, Rudi A; Dunford, James E; Kirsten, Marie L; Seabra, Miguel C; Bala, Joy L; Marma, Mong S; Rogers, Michael J; Coxon, Fraser P

    2010-05-13

    3-(3-Pyridyl)-2-hydroxy-2-phosphonopropanoic acid (3-PEHPC, 1) is a phosphonocarboxylate (PC) analogue of 2-(3-pyridyl)-1-hydroxyethylidenebis(phosphonic acid) (risedronic acid, 2), an osteoporosis drug that decreases bone resorption by inhibiting farnesyl pyrophosphate synthase (FPPS) in osteoclasts, preventing protein prenylation. 1 has lower bone affinity than 2 and weakly inhibits Rab geranylgeranyl transferase (RGGT), selectively preventing prenylation of Rab GTPases. We report here the synthesis and biological studies of 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid (3-IPEHPC, 3), the PC analogue of minodronic acid 4. Like 1, 3 selectively inhibited Rab11 vs. Rap 1A prenylation in J774 cells, and decreased cell viability, but was 33-60x more active in these assays. After resolving 3 by chiral HPLC (>98% ee), we found that (+)-3-E1 was much more potent than (-)-3-E2 in an isolated RGGT inhibition assay, approximately 17x more potent (LED 3 microM) than (-)-3-E2 in inhibiting Rab prenylation in J774 cells and >26x more active in the cell viability assay. The enantiomers of 1 exhibited a 4-fold or smaller potency difference in the RGGT and prenylation inhibition assays.

  12. Determination of Activity of the Enzymes Hypoxanthine Phosphoribosyl Transferase (HPRT) and Adenine Phosphoribosyl Transferase (APRT) in Blood Spots on Filter Paper.

    PubMed

    Auler, Kasie; Broock, Robyn; Nyhan, William L

    2015-07-01

    Hypoxanthine-guanine phosphoribosyl-transferase (HPRT) deficiency is the cause of Lesch-Nyhan disease. Adenine phosphoribosyl-transferase (APRT) deficiency causes renal calculi. The activity of each enzyme is readily determined on spots of whole blood on filter paper. This unit describes a method for detecting deficiencies of HPRT and APRT. Copyright © 2015 John Wiley & Sons, Inc.

  13. Single-step purification and h.p.l.c. analysis of glutathione transferase 8-8 in rat tissues.

    PubMed Central

    Meyer, D J; Lalor, E; Coles, B; Kispert, A; Alin, P; Mannervik, B; Ketterer, B

    1989-01-01

    GSSG selectively elutes two GSH transferases from a mixture of rat GSH transferases bound to a GSH-agarose affinity matrix. One is a form of GSH transferase 1-1 and the other is shown to be GSH transferase 8-8. By using tissues that lack this form of GSH transferase 1-1 (e.g. lung), GSH transferase 8-8 may thus be purified from cytosol in a single step. Quantitative analysis of the tissue distribution of GSH transferase 8-8 was obtained by h.p.l.c. PMID:2764904

  14. 1-(Fluoroalkylidene)-1,1-bisphosphonic Acids are Potent and Selective Inhibitors of the Enzymatic Activity of Toxoplasma gondii Farnesyl Pyrophosphate Synthase

    PubMed Central

    Szajnman, Sergio H.; Rosso, Valeria S.; Malayil, Leena; Smith, Alyssa; Moreno, Silvia N. J.; Docampo, Roberto

    2012-01-01

    α-Fluorinated-1,1-bisphosphonic acids derived from fatty acids were designed, synthesized and biologically evaluated against Trypanosoma cruzi, the etiologic agent of Chagas disease and against Toxoplasma gondii, the responsible agent of toxoplasmosis and also towards the target parasitic enzymes farnesyl pyrophosphate synthase of T. cruzi (TcFPPS) and T gondii (TgFPPS), respectively. Interestingly, 1-fluorononylidene-1,1-bisphosphonic acid (compound 43) has proven to be an extremely potent inhibitor of the enzymatic activity of TgFPPS at the low nanomolar range exhibiting an IC50 of 30 nM. This compound was two-fold more potent than risedronate (IC50 = 74 nM) taken as a positive control. This enzymatic activity was associated to a strong cell growth inhibition against tachyzoites of T. gondii having an IC50 value of 2.7 μM. PMID:22215028

  15. Cloning of a cDNA that encodes farnesyl diphosphate synthase and the blue-light-induced expression of the corresponding gene in the leaves of rice plants.

    PubMed

    Sanmiya, K; Iwasaki, T; Matsuoka, M; Miyao, M; Yamamoto, N

    1997-02-28

    A cDNA encoding farnesyl diphosphate synthase (FPPS), a key enzyme in isoprenoid biosynthesis, was isolated from a cDNA library constructed from mRNA that had been prepared from etiolated rice (Oriza sativa L. variety Nipponbare) seedlings after three hours of illumination by a subtraction method. The putative polypeptide deduced from the 1289 bp nucleotide sequence consisted of 353 amino acids and had a molecular mass of 40 676 Da. The predicted amino acid sequence exhibited high homology to those of FPPS from Arabidopsis (73% to type 1, 72% to type 2) and white lupin (74%). Southern blot analysis showed that the rice genome might contain only one gene for FPPS. The highest level of expression of the gene was demonstrated in leaves by RNA blot analysis. Moreover, light, in particular blue light, effectively enhanced expression of the gene.

  16. The purification of 3,3-dimethylallyl- and geranyl-transferase and of isopentenyl pyrophosphate isomerase from pig liver

    PubMed Central

    Holloway, P. W.; Popják, G.

    1967-01-01

    The enzyme catalysing the synthesis of farnesyl pyrophosphate from dimethylallyl pyrophosphate and isopentenyl pyrophosphate, or from geranyl pyrophosphate and isopentenyl pyrophosphate, has been purified 100-fold from homogenates of pig liver. The enzyme has optimum pH 7·9 and requires Mg2+ as activator in preference to Mn2+; it is inhibited by iodoacetamide, N-ethylmaleimide, p-hydroxymercuribenzoate and phosphate ions in addition to the products of the reaction, inorganic pyrophosphate and farnesyl pyrophosphate. From product-inhibition studies of the geranyltransferase reaction, the order of addition of substrates to and release of products from the enzyme has been deduced: geranyl pyrophosphate combines with the enzyme first, followed by isopentenyl pyrophosphate. Farnesyl pyrophosphate dissociates from the enzyme before inorganic pyrophosphate. The existence of isopentenyl pyrophosphate isomerase in liver is confirmed. Methods for the preparation of the pyrophosphate esters of isopentenol, 3,3-dimethylallyl alcohol, geraniol and farnesol are also described. PMID:4292002

  17. Suppressing Farnesyl Diphosphate Synthase Alters Chloroplast Development and Triggers Sterol-Dependent Induction of Jasmonate- and Fe-Related Responses1[OPEN

    PubMed Central

    Andrade, Paola; Caudepón, Daniel; Arró, Montserrat

    2016-01-01

    Farnesyl diphosphate synthase (FPS) catalyzes the synthesis of farnesyl diphosphate from isopentenyl diphosphate and dimethylallyl diphosphate. Arabidopsis (Arabidopsis thaliana) contains two genes (FPS1 and FPS2) encoding FPS. Single fps1 and fps2 knockout mutants are phenotypically indistinguishable from wild-type plants, while fps1/fps2 double mutants are embryo lethal. To assess the effect of FPS down-regulation at postembryonic developmental stages, we generated Arabidopsis conditional knockdown mutants expressing artificial microRNAs devised to simultaneously silence both FPS genes. Induction of silencing from germination rapidly caused chlorosis and a strong developmental phenotype that led to seedling lethality. However, silencing of FPS after seed germination resulted in a slight developmental delay only, although leaves and cotyledons continued to show chlorosis and altered chloroplasts. Metabolomic analyses also revealed drastic changes in the profile of sterols, ubiquinones, and plastidial isoprenoids. RNA sequencing and reverse transcription-quantitative polymerase chain reaction transcriptomic analysis showed that a reduction in FPS activity levels triggers the misregulation of genes involved in biotic and abiotic stress responses, the most prominent one being the rapid induction of a set of genes related to the jasmonic acid pathway. Down-regulation of FPS also triggered an iron-deficiency transcriptional response that is consistent with the iron-deficient phenotype observed in FPS-silenced plants. The specific inhibition of the sterol biosynthesis pathway by chemical and genetic blockage mimicked these transcriptional responses, indicating that sterol depletion is the primary cause of the observed alterations. Our results highlight the importance of sterol homeostasis for normal chloroplast development and function and reveal important clues about how isoprenoid and sterol metabolism is integrated within plant physiology and development. PMID

  18. Geranylgeranyl diphosphate synthase in fission yeast is a heteromer of farnesyl diphosphate synthase (FPS), Fps1, and an FPS-like protein, Spo9, essential for sporulation.

    PubMed

    Ye, Yanfang; Fujii, Makoto; Hirata, Aiko; Kawamukai, Makoto; Shimoda, Chikashi; Nakamura, Taro

    2007-09-01

    Both farnesyl diphosphate synthase (FPS) and geranylgeranyl diphosphate synthase (GGPS) are key enzymes in the synthesis of various isoprenoid-containing compounds and proteins. Here, we describe two novel Schizosaccharomyces pombe genes, fps1(+) and spo9(+), whose products are similar to FPS in primary structure, but whose functions differ from one another. Fps1 is essential for vegetative growth, whereas, a spo9 null mutant exhibits temperature-sensitive growth. Expression of fps1(+), but not spo9(+), suppresses the lethality of a Saccharomyces cerevisiae FPS-deficient mutant and also restores ubiquinone synthesis in an Escherichia coli ispA mutant, which lacks FPS activity, indicating that S. pombe Fps1 in fact functions as an FPS. In contrast to a typical FPS gene, no apparent GGPS homologues have been found in the S. pombe genome. Interestingly, although neither fps1(+) nor spo9(+) expression alone in E. coli confers clear GGPS activity, coexpression of both genes induces such activity. Moreover, the GGPS activity is significantly reduced in the spo9 mutant. In addition, the spo9 mutation perturbs the membrane association of a geranylgeranylated protein, but not that of a farnesylated protein. Yeast two-hybrid and coimmunoprecipitation analyses indicate that Fps1 and Spo9 physically interact. Thus, neither Fps1 nor Spo9 alone functions as a GGPS, but the two proteins together form a complex with GGPS activity. Because spo9 was originally identified as a sporulation-deficient mutant, we show here that expansion of the forespore membrane is severely inhibited in spo9Delta cells. Electron microscopy revealed significant accumulation membrane vesicles in spo9Delta cells. We suggest that lack of GGPS activity in a spo9 mutant results in impaired protein prenylation in certain proteins responsible for secretory function, thereby inhibiting forespore membrane formation.

  19. [Oral ulcers].

    PubMed

    Bascones-Martínez, Antonio; Figuero-Ruiz, Elena; Esparza-Gómez, Germán Carlos

    2005-10-29

    Ulcers commonly occur in the oral cavity, their main symptom being pain. There are different ways to classify oral ulcers. The most widely accepted form divides them into acute ulcers--sudden onset and short lasting--and chronic ulcers--insidious onset and long lasting. Commonest acute oral ulcers include traumatic ulcer, recurrent aphthous stomatitis, viral and bacterial infections and necrotizing sialometaplasia. On the other hand, oral lichen planus, oral cancer, benign mucous membrane pemphigoid, pemphigus and drug-induced ulcers belong to the group of chronic oral ulcers. It is very important to make a proper differential diagnosis in order to establish the appropriate treatment for each pathology.

  20. Herpes - oral

    MedlinePlus

    Cold sore; Fever blister; Oral herpes simplex; Herpes labialis; Herpes simplex ... Oral herpes is a common infection of the mouth area. It is caused by ... genital herpes . However, sometimes HSV-2 is spread to the ...

  1. Oral candidosis.

    PubMed

    McIntyre, G T

    2001-04-01

    Oral candidoses are frequently encountered in the practice of dentistry. Although most oral candidoses are symptomless, the can indicate the presence of an underlying systemic disease, and the persistence of oral candidosis following appropriate conventional management may be one of the first signs of undiagnosed immunosuppression. The opportunistic pathogen Candida albicans is the most commonly isolated species from oral candidal lesions; however, the non-albicans Candida spp. are also implicated in the aetiology of oral candidoses. The effective management of oral candidosis is dependent on an accurate diagnosis, identification and elimination of any predisposing factors (where possible), and the prescription of either topical or systemic antifungal agents. Oral candidosis may have significant implications for the general health of immunosuppressed patients, particularly when caused by the non-albicans spp. and, in cases of severe immunosuppression, systemic candidosis can be life-threatening. This article outlines the clinical presentation and appropriate management for the commonly presenting oral candidal conditions.

  2. Oral cancer

    MedlinePlus

    Cancer - mouth; Mouth cancer; Head and neck cancer; Squamous cell cancer - mouth; Malignant neoplasm - oral ... Oral cancer most commonly involves the lips or the tongue. It may also occur on the: Cheek lining Floor ...

  3. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a) Identification...

  4. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1315 Galactose-1-phosphate uridyl transferase test system. (a) Identification...

  5. Acrolein-detoxifying isozymes of glutathione transferase in plants.

    PubMed

    Mano, Jun'ichi; Ishibashi, Asami; Muneuchi, Hitoshi; Morita, Chihiro; Sakai, Hiroki; Biswas, Md Sanaullah; Koeduka, Takao; Kitajima, Sakihito

    2017-02-01

    Acrolein is a lipid-derived highly reactive aldehyde, mediating oxidative signal and damage in plants. We found acrolein-scavenging glutathione transferase activity in plants and purified a low K M isozyme from spinach. Various environmental stressors on plants cause the generation of acrolein, a highly toxic aldehyde produced from lipid peroxides, via the promotion of the formation of reactive oxygen species, which oxidize membrane lipids. In mammals, acrolein is scavenged by glutathione transferase (GST; EC 2.5.1.18) isozymes of Alpha, Pi, and Mu classes, but plants lack these GST classes. We detected the acrolein-scavenging GST activity in four species of plants, and purified an isozyme showing this activity from spinach (Spinacia oleracea L.) leaves. The isozyme (GST-Acr), obtained after an affinity chromatography and two ion exchange chromatography steps, showed the K M value for acrolein 93 μM, the smallest value known for acrolein-detoxifying enzymes in plants. Peptide sequence homology search revealed that GST-Acr belongs to the GST Tau, a plant-specific class. The Arabidopsis thaliana GST Tau19, which has the closest sequence similar to spinach GST-Acr, also showed a high catalytic efficiency for acrolein. These results suggest that GST plays as a scavenger for acrolein in plants.

  6. Characterization of two Arabidopsis thaliana glutathione S-transferases.

    PubMed

    Nutricati, Eliana; Miceli, Antonio; Blando, Federica; De Bellis, Luigi

    2006-09-01

    Glutathione S-transferases (GST) are multifunctional proteins encoded by a large gene family, divided on the basis of sequence identity into phi, tau, theta, zeta and lambda classes. The phi and tau classes are present only in plants. GSTs appear to be ubiquitous in plants and are involved in herbicide detoxification and stress response, but little is known about the precise role of GSTs in normal plant physiology and during biotic and abiotic stress response. Two cDNAs representing the two plant classes tau and phi, AtGSTF9 and AtGSTU26, were expressed in vitro and the corresponding proteins were analysed. Both GSTs were able to catalyse a glutathione conjugation to 1-chloro-2,4-dinitrobenzene (CDNB), but they were inactive as transferases towards p-nitrobenzylchloride (pNBC). AtGSTF9 showed activity towards benzyl isothiocyanate (BITC) and an activity as glutathione peroxidase with cumene hydroperoxide (CumHPO). AtGSTU26 was not active as glutathione peroxidase and towards BITC. RT-PCR analysis was used to evaluate the expression of the two genes in response to treatment with herbicides and safeners, chemicals, low and high temperature. Our results reveal that AtGSTU26 is induced by the chloroacetanilide herbicides alachlor and metolachlor and the safener benoxacor, and after exposure to low temperatures. In contrast, AtGSTF9 seems not to be influenced by the treatments employed.

  7. Characterization of glutathione S-transferase of Taenia solium.

    PubMed

    Vibanco-Pérez, N; Jiménez, L; Merchant, M T; Landa, A

    1999-06-01

    A Taenia solium glutathione-S-transferase fraction (SGSTF) was isolated from a metacestode crude extract by affinity chromatography on reduced glutathione (GSH)-sepharose. The purified fraction displayed a specific glutathione S-transferase (GST) activity of 2.8 micromol/min/mg and glutathione peroxidase selenium-independent activity of 0.22 micromol/min/mg. Enzymatic characterization of the fraction suggested that the activity was closer to the mammalian mu-class GSTs. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and enzyme activity analysis showed that the fraction was composed of a major band of Mr = 26 kd and that the active enzyme was dimeric. Immunohistochemical studies using specific antibodies against the major 26-kd band of the SGSTF indicated that GST protein was present in the tegument, parenchyma, protonephridial, and tegumentary cytons of the T. solium metacestode. Antibodies generated against the SGSTF tested in western blot showed cross-reactivity against GSTs purified from Taenia saginata, T. taeniaeformis, and T. crassiceps, but did not react with GSTs from Schistosoma mansoni, or mice, rabbit, and pig liver tissue. Furthermore, immunization of mice with SGSTF reduced the metacestode burden up to 74.2%. Our findings argue in favor of GST having an important role in the survival of T. solium in its hosts.

  8. Interaction of pleuromutilin derivatives with the ribosomal peptidyl transferase center.

    PubMed

    Long, Katherine S; Hansen, Lykke H; Jakobsen, Lene; Vester, Birte

    2006-04-01

    Tiamulin is a pleuromutilin antibiotic that is used in veterinary medicine. The recently published crystal structure of a tiamulin-50S ribosomal subunit complex provides detailed information about how this drug targets the peptidyl transferase center of the ribosome. To promote rational design of pleuromutilin-based drugs, the binding of the antibiotic pleuromutilin and three semisynthetic derivatives with different side chain extensions has been investigated using chemical footprinting. The nucleotides A2058, A2059, G2505, and U2506 are affected in all of the footprints, suggesting that the drugs are similarly anchored in the binding pocket by the common tricyclic mutilin core. However, varying effects are observed at U2584 and U2585, indicating that the side chain extensions adopt distinct conformations within the cavity and thereby affect the rRNA conformation differently. An Escherichia coli L3 mutant strain is resistant to tiamulin and pleuromutilin, but not valnemulin, implying that valnemulin is better able to withstand an altered rRNA binding surface around the mutilin core. This is likely due to additional interactions made between the valnemulin side chain extension and the rRNA binding site. The data suggest that pleuromutilin drugs with enhanced antimicrobial activity may be obtained by maximizing the number of interactions between the side chain moiety and the peptidyl transferase cavity.

  9. Interaction of Pleuromutilin Derivatives with the Ribosomal Peptidyl Transferase Center

    PubMed Central

    Long, Katherine S.; Hansen, Lykke H.; Jakobsen, Lene; Vester, Birte

    2006-01-01

    Tiamulin is a pleuromutilin antibiotic that is used in veterinary medicine. The recently published crystal structure of a tiamulin-50S ribosomal subunit complex provides detailed information about how this drug targets the peptidyl transferase center of the ribosome. To promote rational design of pleuromutilin-based drugs, the binding of the antibiotic pleuromutilin and three semisynthetic derivatives with different side chain extensions has been investigated using chemical footprinting. The nucleotides A2058, A2059, G2505, and U2506 are affected in all of the footprints, suggesting that the drugs are similarly anchored in the binding pocket by the common tricyclic mutilin core. However, varying effects are observed at U2584 and U2585, indicating that the side chain extensions adopt distinct conformations within the cavity and thereby affect the rRNA conformation differently. An Escherichia coli L3 mutant strain is resistant to tiamulin and pleuromutilin, but not valnemulin, implying that valnemulin is better able to withstand an altered rRNA binding surface around the mutilin core. This is likely due to additional interactions made between the valnemulin side chain extension and the rRNA binding site. The data suggest that pleuromutilin drugs with enhanced antimicrobial activity may be obtained by maximizing the number of interactions between the side chain moiety and the peptidyl transferase cavity. PMID:16569865

  10. Nucleotidyl transferase assisted DNA labeling with different click chemistries.

    PubMed

    Winz, Marie-Luise; Linder, Eva Christina; André, Timon; Becker, Juliane; Jäschke, Andres

    2015-09-30

    Here, we present a simple, modular and efficient strategy that allows the 3'-terminal labeling of DNA, regardless of whether it has been chemically or enzymatically synthesized or isolated from natural sources. We first incorporate a range of modified nucleotides at the 3'-terminus, using terminal deoxynucleotidyl transferase. In the second step, we convert the incorporated nucleotides, using either of four highly efficient click chemistry-type reactions, namely copper-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, Staudinger ligation or Diels-Alder reaction with inverse electron demand. Moreover, we create internal modifications, making use of either ligation or primer extension, after the nucleotidyl transferase step, prior to the click reaction. We further study the influence of linker variants on the reactivity of azides in different click reactions. We find that different click reactions exhibit distinct substrate preferences, a fact that is often overlooked, but should be considered when labeling oligonucleotides or other biomolecules with click chemistry. Finally, our findings allowed us to extend our previously published RNA labeling strategy to the use of a different copper-free click chemistry, namely the Staudinger ligation. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  11. Nucleotidyl transferase assisted DNA labeling with different click chemistries

    PubMed Central

    Winz, Marie-Luise; Linder, Eva Christina; André, Timon; Becker, Juliane; Jäschke, Andres

    2015-01-01

    Here, we present a simple, modular and efficient strategy that allows the 3′-terminal labeling of DNA, regardless of whether it has been chemically or enzymatically synthesized or isolated from natural sources. We first incorporate a range of modified nucleotides at the 3′-terminus, using terminal deoxynucleotidyl transferase. In the second step, we convert the incorporated nucleotides, using either of four highly efficient click chemistry-type reactions, namely copper-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, Staudinger ligation or Diels-Alder reaction with inverse electron demand. Moreover, we create internal modifications, making use of either ligation or primer extension, after the nucleotidyl transferase step, prior to the click reaction. We further study the influence of linker variants on the reactivity of azides in different click reactions. We find that different click reactions exhibit distinct substrate preferences, a fact that is often overlooked, but should be considered when labeling oligonucleotides or other biomolecules with click chemistry. Finally, our findings allowed us to extend our previously published RNA labeling strategy to the use of a different copper-free click chemistry, namely the Staudinger ligation. PMID:26013812

  12. Structure-activity relationships of 4-hydroxyalkenals in the conjugation catalysed by mammalian glutathione transferases.

    PubMed Central

    Danielson, U H; Esterbauer, H; Mannervik, B

    1987-01-01

    The substrate specificities of 15 cytosolic glutathione transferases from rat, mouse and man have been explored by use of a homologous series of 4-hydroxyalkenals, extending from 4-hydroxypentenal to 4-hydroxypentadecenal. Rat glutathione transferase 8-8 is exceptionally active with the whole range of 4-hydroxyalkenals, from C5 to C15. Rat transferase 1-1, although more than 10-fold less efficient than transferase 8-8, is the second most active transferase with the longest chain length substrates. Other enzyme forms showing high activities with these substrates are rat transferase 4-4 and human transferase mu. The specificity constants, kcat./Km, for the various enzymes have been determined with the 4-hydroxyalkenals. From these constants the incremental Gibbs free energy of binding to the enzyme has been calculated for the homologous substrates. The enzymes responded differently to changes in the length of the hydrocarbon side chain and could be divided into three groups. All glutathione transferases displayed increased binding energy in response to increased hydrophobicity of the substrate. For some of the enzymes, steric limitations of the active site appear to counteract the increase in binding strength afforded by increased chain length of the substrate. Comparison of the activities with 4-hydroxyalkenals and other activated alkenes provides information about the active-site properties of certain glutathione transferases. The results show that the ensemble of glutathione transferases in a given species may serve an important physiological role in the conjugation of the whole range of 4-hydroxyalkenals. In view of its high catalytic efficiency with all the homologues, rat glutathione transferase 8-8 appears to have evolved specifically to serve in the detoxication of these reactive compounds of oxidative metabolism. PMID:3426557

  13. A Xanthomonas uridine 5'-monophosphate transferase inhibits plant immune kinases.

    PubMed

    Feng, Feng; Yang, Fan; Rong, Wei; Wu, Xiaogang; Zhang, Jie; Chen, She; He, Chaozu; Zhou, Jian-Min

    2012-04-15

    Plant innate immunity is activated on the detection of pathogen-associated molecular patterns (PAMPs) at the cell surface, or of pathogen effector proteins inside the plant cell. Together, PAMP-triggered immunity and effector-triggered immunity constitute powerful defences against various phytopathogens. Pathogenic bacteria inject a variety of effector proteins into the host cell to assist infection or propagation. A number of effector proteins have been shown to inhibit plant immunity, but the biochemical basis remains unknown for the vast majority of these effectors. Here we show that the Xanthomonas campestris pathovar campestris type III effector AvrAC enhances virulence and inhibits plant immunity by specifically targeting Arabidopsis BIK1 and RIPK, two receptor-like cytoplasmic kinases known to mediate immune signalling. AvrAC is a uridylyl transferase that adds uridine 5'-monophosphate to and conceals conserved phosphorylation sites in the activation loop of BIK1 and RIPK, reducing their kinase activity and consequently inhibiting downstream signalling.

  14. Glutathione S-transferase class {pi} polymorphism in baboons

    SciTech Connect

    Aivaliotis, M.J.; Cantu, T.; Gilligan, R.

    1995-02-01

    Glutathione S-transferase (GST) comprises a family of isozymes with broad substrate specificities. One or more GST isozymes are present in most animal tissues and function in several detoxification pathways through the conjugation of reduced glutathione with various electrophiles, thereby reducing their potential toxicity. Four soluble GST isozymes encoded by genes on different chromosomes have been identified in humans. The acidic class pi GST, GSTP (previously designated GST-3), is widely distributed in adult tissues and appears to be the only GST isozyme present in leukocytes and placenta. Previously reported electrophoretic analyses of erythrocyte and leukocyte extracts revealed single bands of activity, which differed slightly in mobility between the two cell types, or under other conditions, a two-banded pattern. To our knowledge, no genetically determined polymorphisms have previously been reported in GSTP from any species. We now report a polymorphism of GSTP in baboon leukocytes, and present family data that verifies autosomal codominant inheritance. 14 refs., 2 figs., 1 tab.

  15. Thermodynamics of Enzyme-Catalyzed Reactions: Part 2. Transferases

    NASA Astrophysics Data System (ADS)

    Goldberg, Robert N.; Tewari, Yadu B.

    1994-07-01

    Equilibrium constants and enthalpy changes for reactions catalyzed by the transferase class of enzymes have been compiled. For each reaction the following information is given: the reference for the data; the reaction studied; the name of the enzyme used and its Enzyme Commission number; the method of measurement; the conditions of measurement [temperature, pH, ionic strength, and the buffer(s) and cofactor(s) used]; the data and an evaluation of it; and, sometimes, commentary on the data and on any corrections which have been applied to it or any calculations for which the data have been used. The data from 285 references have been examined and evaluated. Chemical Abstract Service registry numbers are given for the substances involved in these various reactions. There is a cross reference between the substances and the Enzyme Commission numbers of the enzymes used to catalyze the reactions in which the substances participate.

  16. The inhibition of human farnesyl pyrophosphate synthase by nitrogen-containing bisphosphonates. Elucidating the role of active site threonine 201 and tyrosine 204 residues using enzyme mutants☆

    PubMed Central

    Tsoumpra, Maria K.; Muniz, Joao R.; Barnett, Bobby L.; Kwaasi, Aaron A.; Pilka, Ewa S.; Kavanagh, Kathryn L.; Evdokimov, Artem; Walter, Richard L.; Von Delft, Frank; Ebetino, Frank H.; Oppermann, Udo; Russell, R. Graham G.; Dunford, James E.

    2015-01-01

    Farnesyl pyrophosphate synthase (FPPS) is the major molecular target of nitrogen-containing bisphosphonates (N-BPs), used clinically as bone resorption inhibitors. We investigated the role of threonine 201 (Thr201) and tyrosine 204 (Tyr204) residues in substrate binding, catalysis and inhibition by N-BPs, employing kinetic and crystallographic studies of mutated FPPS proteins. Mutants of Thr201 illustrated the importance of the methyl group in aiding the formation of the Isopentenyl pyrophosphate (IPP) binding site, while Tyr204 mutations revealed the unknown role of this residue in both catalysis and IPP binding. The interaction between Thr201 and the side chain nitrogen of N-BP was shown to be important for tight binding inhibition by zoledronate (ZOL) and risedronate (RIS), although RIS was also still capable of interacting with the main-chain carbonyl of Lys200. The interaction of RIS with the phenyl ring of Tyr204 proved essential for the maintenance of the isomerized enzyme-inhibitor complex. Studies with conformationally restricted analogues of RIS reaffirmed the importance of Thr201 in the formation of hydrogen bonds with N-BPs. In conclusion we have identified new features of FPPS inhibition by N-BPs and revealed unknown roles of the active site residues in catalysis and substrate binding. PMID:26318908

  17. Overexpression of erg20 gene encoding farnesyl pyrophosphate synthase has contrasting effects on activity of enzymes of the dolichyl and sterol branches of mevalonate pathway in Trichoderma reesei.

    PubMed

    Piłsyk, Sebastian; Perlińska-Lenart, Urszula; Górka-Nieć, Wioletta; Graczyk, Sebastian; Antosiewicz, Beata; Zembek, Patrycja; Palamarczyk, Grażyna; Kruszewska, Joanna S

    2014-07-10

    The mevalonate pathway is the most diverse metabolic route resulting in the biosynthesis of at least 30,000 isoprenoid compounds, many of which, such as sterols or dolichols, are indispensable for living cells. In the filamentous fungus Trichoderma of major biotechnological interest isoprenoid metabolites are also involved in the biocontrol processes giving the mevalonate pathway an additional significance. On the other hand, little is known about genes coding for enzymes of the mevalonate pathway in Trichoderma. Here, we present cloning and functional analysis of the erg20 gene from Trichoderma reesei coding for farnesyl pyrophosphate (FPP) synthase (EC 2.5.1.10), an enzyme located at the branching point of the mevalonate pathway. Expression of the gene in a thermosensitive erg20-2 mutant of Saccharomyces cerevisiae impaired in the FPP synthase activity suppressed the thermosensitive phenotype. The same gene overexpressed in T. reesei significantly enhanced the FPP synthase activity and also stimulated the activity of cis-prenyltransferase, an enzyme of the dolichyl branch of the mevalonate pathway. Unexpectedly, the activity of squalene synthase from the other, sterol branch, was significantly decreased without, however, affecting ergosterol level.

  18. Investigating the efficacy of pamidronate, a chemical inhibitor of farnesyl pyrophosphate synthase, in the inhibition of influenza virus infection in vitro and in vivo.

    PubMed

    Tan, Kai Sen; Ng, Wai Chii; Seet, Ju Ee; Olfat, Farzad; Engelward, Bevin P; Chow, Vincent T K

    2014-01-01

    Influenza A virus has caused significant pandemics in the past decades, including the H1N1‑2009 pandemic. Viperin is an interferon‑inducible protein that acts as a broad‑spectrum antiviral protein via the inhibition of farnesyl pyrophosphate synthase (FPPS). To mimic this activity of viperin, the present study investigated the effectiveness of a commercially available FPPS inhibitor (pamidronate) as an inhibitor of influenza virus infection in vitro and in vivo. HeLaM cells were treated with pamidronate to determine its effect on the replication of influenza virus A/H1N1/WSN/1933. C57BL/6 mice were also subjected to intratracheal pamidronate treatment regimes prior to and following lethal influenza challenge. Treatment with the FPPS inhibitor in vitro resulted in a considerable reduction in the viral titer of ~1 log and diminished lipid raft formation without cellular toxicity, thus mimicking the antiviral effect of viperin. However, pamidronate lacked efficacy in vivo and was associated with increased pulmonary damage, most likely due to the complexity of drug‑host interactions in the infected mice. Further studies are warranted on pamidronate treatment in other infectious diseases that are more susceptible to FPPS inhibition.

  19. Molecular characterization of two isoforms of a farnesyl pyrophosphate synthase gene in wheat and their roles in sesquiterpene synthesis and inducible defence against aphid infestation.

    PubMed

    Zhang, Yan; Li, Zhi-Xia; Yu, Xiu-Dao; Fan, Jia; Pickett, John A; Jones, Huw D; Zhou, Jing-Jiang; Birkett, Michael A; Caulfield, John; Napier, Johnathan A; Zhao, Guang-Yao; Cheng, Xian-Guo; Shi, Yi; Bruce, Toby J A; Xia, Lan-Qin

    2015-05-01

    Aphids are important pests of wheat (Triticum aestivum) that affect crop production globally. Herbivore-induced emission of sesquiterpenes can repel pests, and farnesyl pyrophosphate synthase (FPS) is a key enzyme involved in sesquiterpene biosynthesis. However, fps orthologues in wheat and their functional roles in sesquiterpene synthesis and defence against aphid infestation are unknown. Here, two fps isoforms, Tafps1 and Tafps2, were identified in wheat. Quantitative real-time polymerase chain reaction (qRT-PCR) and in vitro catalytic activity analyses were conducted to investigate expression patterns and activity. Heterologous expression of these isoforms in Arabidopsis thaliana, virus-induced gene silencing (VIGS) in wheat and aphid behavioural assays were performed to understand the functional roles of these two isoforms. We demonstrated that Tafps1 and Tafps2 played different roles in induced responses to aphid infestation and in sesquiterpene synthesis. Heterologous expression in A. thaliana resulted in repulsion of the peach aphid (Myzus persicae). Wheat plants with these two isoforms transiently silenced were significantly attractive to grain aphid (Sitobion avenae). Our results provide new insights into induced defence against aphid herbivory in wheat, in particular, the different roles of the two Tafps isoforms in both sesquiterpene biosynthesis and defence against aphid infestation.

  20. Strengthening Triterpene Saponins Biosynthesis by Over-Expression of Farnesyl Pyrophosphate Synthase Gene and RNA Interference of Cycloartenol Synthase Gene in Panax notoginseng Cells.

    PubMed

    Yang, Yan; Ge, Feng; Sun, Ying; Liu, Diqiu; Chen, Chaoyin

    2017-04-05

    To conform to the multiple regulations of triterpene biosynthesis, the gene encoding farnesyl pyrophosphate synthase (FPS) was transformed into Panax notoginseng (P. notoginseng) cells in which RNA interference (RNAi) of the cycloartenol synthase (CAS) gene had been accomplished. Transgenic cell lines showed both higher expression levels of FPS and lower expression levels of CAS compared to the wild-type (WT) cells. In the triterpene and phytosterol analysis, transgenic cell lines provided a higher accumulation of total triterpene saponins, and a lower amount of phytosterols in comparison with the WT cells. Compared with the cells in which RNAi of the CAS gene was achieved, the cells with simultaneously over-expressed FPS and silenced CAS showed higher triterpene contents. These results demonstrate that over-expression of FPS can break the rate-limiting reaction catalyzed by FPS in the triterpene saponins biosynthetic pathway; and inhibition of CAS expression can decrease the synthesis metabolic flux of the phytosterol branch. Thus, more precursors flow in the direction of triterpene synthesis, and ultimately promote the accumulation of P. notoginseng saponins. Meanwhile, silencing and over-expressing key enzyme genes simultaneously is more effective than just manipulating one gene in the regulation of saponin biosynthesis.

  1. Oral Testing.

    ERIC Educational Resources Information Center

    de Charruf, Laurie Frey

    1984-01-01

    Oral tests for speaking skills evaluate two major skills: linguistic competence, including accuracy of pronunciation, vocabulary, and structure, and communication ease. Four factors affect students' oral performance: verbal intelligence, short-term auditory and visual memory, sound-symbol association skill, and grammatical analysis. Personality…

  2. Oral cysticercosis.

    PubMed

    Chunduri, Nagendra S; Goteki, Venkateswarulu; Gelli, Vamsi; Madasu, Krishnaveni

    2013-03-01

    Cysticercosis is a common disease in developing countries, but oral lesions caused by this parasitic infestation are rare. We report here a rare case of oral cysticercosis in a 17 year old male who sought treatment for an asymptomatic nodule of the lower lip that had previously been diagnosed as a mucocele.

  3. Oral Thrush

    MedlinePlus

    ... more susceptible to oral thrush infection: HIV/AIDS. Human immunodeficiency virus (HIV) — the virus that causes AIDS — damages or destroys cells of your immune system, making you more susceptible to opportunistic infections that your body would normally resist. Repeated bouts of oral thrush, ...

  4. Glucosylceramide transferase in Giardia preferentially catalyzes the synthesis of galactosylceramide during encystation.

    PubMed

    Robles-Martinez, Leobarda; Mendez, Tavis L; Apodaca, Jennifer; Das, Siddhartha

    2017-01-01

    The stage differentiation from trophozoite to cyst (i.e., encystation) is an essential step for Giardia to survive outside its human host and spread the infection via the fecal-oral route. We have previously shown that Giardia expresses glucosylceramide transferase 1 (GlcT1) enzyme, the activity of which is elevated during encystation. We have also reported that blocking the activity of gGlcT1 interferes with the biogenesis of encystation-specific vesicles (ESVs) and cyst viability in Giardia. To further understand the role of this enzyme and how it regulates encystation, we overexpressed, knocked down, and rescued the giardial GlcT1 (gGlcT1) gene and measured its enzymatic activity in live parasites as well as in isolated membrane fractions using NBD-ceramide and UDP-glucose or UDP-galactose. We observed that gGlcT1 is able to catalyze the synthesis of both glucosylceramide (GlcCer) and galactosylceramide (GalCer), however the synthesis of GalCer is 2-3 fold higher than of GlcCer. Although both activities follow Michaelis-Menten kinetics, the bindings of UDP-glucose and UDP-galactose with the enzyme appear to be non-competitive and independent of each other. The modulation of gGlcT1 synthesis concomitantly influenced the expression cyst-wall protein (CWP) and overall encystation. We propose that gGlcT1 is a unique enzyme and that Giardia uses this enzyme to synthesize both GlcCer and GalCer to facilitate the process of encystation/cyst production.

  5. Increased transcription of Glutathione S-transferases in acaricide exposed scabies mites

    PubMed Central

    2010-01-01

    Background Recent evidence suggests that Sarcoptes scabiei var. hominis mites collected from scabies endemic communities in northern Australia show increasing tolerance to 5% permethrin and oral ivermectin. Previous findings have implicated detoxification pathways in developing resistance to these acaricides. We investigated the contribution of Glutathione S-transferase (GST) enzymes to permethrin and ivermectin tolerance in scabies mites using biochemical and molecular approaches. Results Increased in vitro survival following permethrin exposure was observed in S. scabiei var. hominis compared to acaricide naïve mites (p < 0.0001). The addition of the GST inhibitor diethyl maleate restored in vitro permethrin susceptibility, confirming GST involvement in permethrin detoxification. Assay of GST enzymatic activity in mites demonstrated that S. scabiei var. hominis mites showed a two-fold increase in activity compared to naïve mites (p < 0.0001). Increased transcription of three different GST molecules was observed in permethrin resistant S. scabiei var. canis- mu 1 (p < 0.0001), delta 1 (p < 0.001), and delta 3 (p < 0.0001). mRNA levels of GST mu 1, delta 3 and P-glycoprotein also significantly increased in S. scabiei var. hominis mites collected from a recurrent crusted scabies patient over the course of ivermectin treatment. Conclusions These findings provide further support for the hypothesis that increased drug metabolism and efflux mediate permethrin and ivermectin resistance in scabies mites and highlight the threat of emerging acaricide resistance to the treatment of scabies worldwide. This is one of the first attempts to define specific genes involved in GST mediated acaricide resistance at the transcriptional level, and the first application of such studies to S. scabiei, a historically challenging ectoparasite. PMID:20482766

  6. Oral Histoplasmosis.

    PubMed

    Folk, Gillian A; Nelson, Brenda L

    2017-02-20

    A 44-year-old female presented to her general dentist with the chief complaint of a painful mouth sore of 2 weeks duration. Clinical examination revealed an irregularly shaped ulcer of the buccal and lingual attached gingiva of the anterior mandible. A biopsy was performed and microscopic evaluation revealed histoplasmosis. Histoplasmosis, caused by Histoplasma capsulate, is the most common fungal infection in the United States. Oral lesions of histoplasmosis are generally associated with the disseminated form of histoplasmosis and may present as a fungating or ulcerative lesion of the oral mucosa. The histologic findings and differential diagnosis for oral histoplasmosis are discussed.

  7. Inactivation of Anopheles gambiae Glutathione Transferase ε2 by Epiphyllocoumarin

    PubMed Central

    Marimo, Patience; Hayeshi, Rose; Mukanganyama, Stanley

    2016-01-01

    Glutathione transferases (GSTs) are part of a major family of detoxifying enzymes that can catalyze the reductive dehydrochlorination of dichlorodiphenyltrichloroethane (DDT). The delta and epsilon classes of insect GSTs have been implicated in conferring resistance to this insecticide. In this study, the inactivation of Anopheles gambiae GSTε2 by epiphyllocoumarin (Tral 1) was investigated. Recombinant AgGSTε2 was expressed in Escherichia coli cells containing a pET3a-AGSTε2 plasmid and purified by affinity chromatography. Tral 1 was shown to inactivate GSTε2 both in a time-dependent manner and in a concentration-dependent manner. The half-life of GSTε2 in the presence of 25 μM ethacrynic acid (ETA) was 22 minutes and with Tral 1 was 30 minutes, indicating that Tral 1 was not as efficient as ETA as an inactivator. The inactivation parameters kinact and KI were found to be 0.020 ± 0.001 min−1 and 7.5 ± 2.1 μM, respectively, after 90 minutes of incubation. Inactivation of GSTε2 by Tral 1 implies that Tral 1 covalently binds to this enzyme in vitro and would be expected to exhibit time-dependent effects on the enzyme in vivo. Tral 1, therefore, would produce irreversible effects when used together with dichlorodiphenyltrichloroethane (DDT) in malaria control programmes where resistance is mediated by GSTs. PMID:26925266

  8. MOF Acetyl Transferase Regulates Transcription and Respiration in Mitochondria.

    PubMed

    Chatterjee, Aindrila; Seyfferth, Janine; Lucci, Jacopo; Gilsbach, Ralf; Preissl, Sebastian; Böttinger, Lena; Mårtensson, Christoph U; Panhale, Amol; Stehle, Thomas; Kretz, Oliver; Sahyoun, Abdullah H; Avilov, Sergiy; Eimer, Stefan; Hein, Lutz; Pfanner, Nikolaus; Becker, Thomas; Akhtar, Asifa

    2016-10-20

    A functional crosstalk between epigenetic regulators and metabolic control could provide a mechanism to adapt cellular responses to environmental cues. We report that the well-known nuclear MYST family acetyl transferase MOF and a subset of its non-specific lethal complex partners reside in mitochondria. MOF regulates oxidative phosphorylation by controlling expression of respiratory genes from both nuclear and mtDNA in aerobically respiring cells. MOF binds mtDNA, and this binding is dependent on KANSL3. The mitochondrial pool of MOF, but not a catalytically deficient mutant, rescues respiratory and mtDNA transcriptional defects triggered by the absence of MOF. Mof conditional knockout has catastrophic consequences for tissues with high-energy consumption, triggering hypertrophic cardiomyopathy and cardiac failure in murine hearts; cardiomyocytes show severe mitochondrial degeneration and deregulation of mitochondrial nutrient metabolism and oxidative phosphorylation pathways. Thus, MOF is a dual-transcriptional regulator of nuclear and mitochondrial genomes connecting epigenetics and metabolism. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. The role of glutathione transferases in cadmium stress.

    PubMed

    Adamis, Paula D B; Gomes, Débora S; Pinto, Maria Lucia C C; Panek, Anita D; Eleutherio, Elis C A

    2004-12-01

    Using Saccharomyces cerevisiae as experimental model, we observed that cells mutated in the GTT1 or GTT2 genes showed twice as much cadmium absorption than the control strain. We proposed that the formation of the cadmium-glutathione complex is dependent on that transferase, since it was previously demonstrated that the cytoplasmic levels of this complex affect cadmium uptake. The addition of glutathione monoethyl ester (GME), a drug that mimics glutathione (GSH), to gtt1Delta cells restored the levels of metal absorption to those of the control strain. However, with respect to gtt2Delta cells, addition of GME did not alter the capacity of removing cadmium from the medium. Taken together, these results suggest that Gtt1 and Gtt2 play different roles in the mechanism of cadmium detoxification. By analyzing the toxic effect of this metal, we verified that gtt2Delta and gsh1Delta cells showed, respectively, higher and lower tolerance to cadmium stress than control cells, suggesting that although GSH plays a relevant role in cell protection, formation of the GSH-Cd conjugate is deleterious to the mechanism of defense.

  10. Crystal structure of E. coli lipoprotein diacylglyceryl transferase.

    PubMed

    Mao, Guotao; Zhao, Yan; Kang, Xusheng; Li, Zhijie; Zhang, Yan; Wang, Xianping; Sun, Fei; Sankaran, Krishnan; Zhang, Xuejun C

    2016-01-05

    Lipoprotein biogenesis is essential for bacterial survival. Phosphatidylglycerol:prolipoprotein diacylglyceryl transferase (Lgt) is an integral membrane enzyme that catalyses the first reaction of the three-step post-translational lipid modification. Deletion of the lgt gene is lethal to most Gram-negative bacteria. Here we present the crystal structures of Escherichia coli Lgt in complex with phosphatidylglycerol and the inhibitor palmitic acid at 1.9 and 1.6 Å resolution, respectively. The structures reveal the presence of two binding sites and support the previously reported structure-function relationships of Lgt. Complementation results of lgt-knockout cells with different mutant Lgt variants revealed critical residues, including Arg143 and Arg239, that are essential for diacylglyceryl transfer. Using a GFP-based in vitro assay, we correlated the activities of Lgt with structural observations. Together, the structural and biochemical data support a mechanism whereby substrate and product, lipid-modified lipobox-containing peptide, enter and leave the enzyme laterally relative to the lipid bilayer.

  11. Glutathione S-transferase polymorphisms in thyroid cancer patients.

    PubMed

    Hernández, Alba; Céspedes, Walkiria; Xamena, Noel; Surrallés, Jordi; Creus, Amadeu; Galofré, Pere; Marcos, Ricardo

    2003-02-10

    Glutathione S-transferases (GST) are enzymes involved in the metabolism of many carcinogens and mutagens, also acting as important free-radical scavengers. The existence of different genetic polymorphisms in human populations has proven to be a susceptibility factor for different tumours. Nevertheless, as far as we know, for thyroid cancer no study has been conducted until now linking its incidence to genetic susceptibility biomarkers. The present investigation has been conducted to detect the possible association between polymorphism at the GSTM1, GSTT1 and GSTP1 genes and thyroid cancer incidence. Thus, 134 thyroid cancer patients and 116 controls, all from the urban district of Barcelona (Spain), have been included in this study. The results indicate that, according to the calculated odds ratio, the frequencies of the different genotypes found in the group of cancer patients do not significantly differ from those values obtained in the controls. This is true for the overall data as well as for the tumour characterization as follicular and papillar types. In addition, none of the possible combinations of mutant genotypes were shown to be risk factors. Finally, when the sex of the patients, the age of tumour onset, and life-style habits were also taken into account, no influence was observed related to the different genotypes. In conclusion, the results obtained in this study clearly suggest that those susceptibility factors related to the different GST polymorphic enzymes are not a predisposing factor in thyroid cancer disease.

  12. Oral mucositis

    MedlinePlus

    ... help keep your mouth moist. Stop wearing your dentures if they cause you to get sores on ... 2016. www.cancer.gov/about-cancer/treatment/side-effects/mouth-throat/oral-complications-hp-pdq . Accessed March ...

  13. Oral pathology.

    PubMed

    Niemiec, Brook A

    2008-05-01

    Oral disease is exceedingly common in small animal patients. In addition, there is a very wide variety of pathologies that are encountered within the oral cavity. These conditions often cause significant pain and/or localized and systemic infection; however, the majority of these conditions have little to no obvious clinical signs. Therefore, diagnosis is not typically made until late in the disease course. Knowledge of these diseases will better equip the practitioner to effectively treat them. This article covers the more common forms of oral pathology in the dog and cat, excluding periodontal disease, which is covered in its own chapter. The various pathologies are presented in graphic form, and the etiology, clinical signs, recommended diagnostic tests, and treatment options are discussed. Pathologies that are covered include: persistent deciduous teeth, fractured teeth, intrinsically stained teeth, feline tooth resorption, caries, oral neoplasia, eosinophilic granuloma complex, lymphoplasmacytic gingivostomatitis, enamel hypoplasia, and "missing" teeth.

  14. Carnitine palmitoyl transferase deficiency with an atypical presentation and ultrastructural mitochondrial abnormalities.

    PubMed Central

    Carey, M P; Poulton, K; Hawkins, C; Murphy, R P

    1987-01-01

    A case of carnitine palmitoyl transferase deficiency presenting in a 72 year old woman with the clinical picture of ophthalmoplegia plus other muscle weakness is reported. Histological and ultrastructural examination showed the features of a mitochondrial myopathy. Images PMID:3655814

  15. N-Acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191): an anti-inflammatory molecule that increases the expression of the aquaglyceroporin, aquaporin-3, in human keratinocytes.

    PubMed

    Fernández, José R; Webb, Corey; Rouzard, Karl; Voronkov, Michael; Huber, Kristen L; Stock, Jeffry B; Stock, Maxwell; Gordon, Joel S; Perez, Eduardo

    2017-03-01

    Isoprenylcysteine (IPC) small molecules were discovered as signal transduction modulating compounds ~25 years ago. More recently, IPC molecules have demonstrated antioxidant and anti-inflammatory properties in a variety of dermal cells as well as antimicrobial activity, representing a novel class of compounds to ameliorate skin conditions and disease. Here, we demonstrate a new IPC compound, N-acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191), which inhibits UVB-induced inflammation blocking pro-inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) production. To investigate further the previously reported hydrating potential of IPC compounds, SIG-1191 was tested for its ability to modulate aquaporin expression. Specifically, aquaporin 3 (AQP3) the most abundant aquaporin found in skin has been reported to play a key role in skin hydration, elasticity and barrier repair. Results show here for the first time that SIG-1191 increases AQP3 expression in both cultured normal human epidermal keratinocytes as well as when applied topically in a three-dimensional (3D) reconstructed human skin equivalent. Additionally, SIG-1191 dose dependently increased AQP3 protein levels, as determined by specific antibody staining, in the epidermis of the 3D skin equivalents. To begin to elucidate which signaling pathways SIG-1191 may be modulating to increase AQP3 levels, we used several pharmacological pathway inhibitors and determined that AQP3 expression is mediated by the Mitogen-activated protein kinase/Extracellular signal-regulated kinase kinase (MEK) pathway. Altogether, these data suggest SIG-1191 represents a new IPC derivative with anti-inflammatory activity that may also promote increased skin hydration based on its ability to increase AQP3 levels.

  16. Comparative assessment of therapeutic safety of norcantharidin, N-farnesyloxy-norcantharimide, and N-farnesyl-norcantharimide against Jurkat T cells relative to human normal lymphoblast

    PubMed Central

    Chang, Ming-Che; Wu, Jin-Yi; Liao, Hui-Fen; Chen, Yu-Jen; Kuo, Cheng-Deng

    2016-01-01

    Abstract The therapeutic safety of an anticancer drug is one of the most important concerns of the physician treating the cancer patient. Half maximal inhibitory concentration (IC50) and hillslope are usually used to represent the strength and sensitivity of an anticancer drug on cancer cells. The therapeutic safety of the anticancer drug can be assessed by comparing the IC50 and hillslope of anticancer drugs on cancer cells relative to normal cells. Since there are situations where “more anticancer activity” implies “more toxicity,” the safety of an anticancer drug in these situations is hard to evaluate by using IC50 and hillslope alone. In a previous study, the “net effect” index was devised to represent the net therapeutic effects of one anticancer drug relative to the other. However, the therapeutic safety of one specific anticancer drug alone was not defined in the “net effect” index. This study introduced the “safety index (SI)” to quantify the degree of safety of an anticancer drug by using 4-parameter logistic model on cancer cells relative to normal cells. The therapeutic safety of norcantharidin (NCTD), N-farnesyloxy-norcantharimide (NOC15), and N-farnesyl-norcantharimide (NC15) in the treatment of Jurkat T cells relative to human normal lymphoblast was compared using the newly defined SI. We found that the SI of NOC15 and NC15 was significantly higher than that of NCTD, suggesting that both NOC15 and NC15 can damage more cancer cells and less normal cells than NCTD. We conclude that both NOC15 and NC15 are safer anticancer drugs than NCTD in the treatment of Jurkat T cells relative to human normal lymphoblast. The SI can be further applied to the screening, developments, and applications of anticancer drugs in the future. PMID:27495082

  17. X-ray Crystal Structure of Aristolochene Synthase from Aspergillus terreus and Evolution of Templates for the Cyclization of Farnesyl Diphosphate

    SciTech Connect

    Shishova,E.; Di Costanzo, L.; Cane, D.; Christianson, D.

    2007-01-01

    Aristolochene synthase from Aspergillus terreus catalyzes the cyclization of the universal sesquiterpene precursor, farnesyl diphosphate, to form the bicyclic hydrocarbon aristolochene. The 2.2 {angstrom} resolution X-ray crystal structure of aristolochene synthase reveals a tetrameric quaternary structure in which each subunit adopts the {alpha}-helical class I terpene synthase fold with the active site in the 'open', solvent-exposed conformation. Intriguingly, the 2.15 {angstrom} resolution crystal structure of the complex with Mg{sup 2+}{sub 3}-pyrophosphate reveals ligand binding only to tetramer subunit D, which is stabilized in the 'closed' conformation required for catalysis. Tetramer assembly may hinder conformational changes required for the transition from the inactive open conformation to the active closed conformation, thereby accounting for the attenuation of catalytic activity with an increase in enzyme concentration. In both conformations, but especially in the closed conformation, the active site contour is highly complementary in shape to that of aristolochene, and a catalytic function is proposed for the pyrophosphate anion based on its orientation with regard to the presumed binding mode of aristolochene. A similar active site contour is conserved in aristolochene synthase from Penicillium roqueforti despite the substantial divergent evolution of these two enzymes, while strikingly different active site contours are found in the sesquiterpene cyclases 5-epi-aristolochene synthase and trichodiene synthase. Thus, the terpenoid cyclase active site plays a critical role as a template in binding the flexible polyisoprenoid substrate in the proper conformation for catalysis. Across the greater family of terpenoid cyclases, this template is highly evolvable within a conserved {alpha}-helical fold for the synthesis of terpene natural products of diverse structure and stereochemistry.

  18. [Reproductive and developmental toxicity study of prednisolone farnesylate (PNF)--study by subcutaneous administration of PNF prior to and in the early stages of pregnancy in rats].

    PubMed

    Taniguchi, H; Yoshitomi, H; Miyazaki, K; Koga, N; Himeno, Y; Hara, Y; Nakamura, M; Tsuji, M; Tanaka, H; Shinomiya, M

    1992-11-01

    A fertility study of Prednisolone farnesylate (PNF), a newly synthesized corticosteroid, was conducted in Sprague-Dawley rats. This compound was administered subcutaneously at dose levels of 0(control), 0.04, 0.2 and 1 mg/kg/day to males for 63 days before mating and during the mating period, and to females for 14 days before mating, through the mating period and until day 7 of pregnancy. Each 24 male and female rats were mated, and females were killed on day 20 of pregnancy to examine their fetuses. 1. In the parental animals, loss of fur or thin fur and incrustation of treated site occurred in male rats treated at doses of 0.2 mg/kg or more and female rats treated at dose of 1 mg/kg, and at the same dose groups, the thinning of skin, atrophy of the thymus and intention of the substance at the injected site were noted. Moreover, body weight gains and food consumption were suppressed in both sexes treated at the dose of 1 mg/kg. 2. Fertility and reproductive ability in both sexes, and estrus cycles in female rats were not affected by administration of PNF. 3. In the fetuses, no embryonic or fetal lethal effect and teratogenic effect were noted. From these results, the no-effect dose levels of PNF on the parental general states, the parental reproductive ability and those of the fetuses are thought to be 0.04 mg/kg/day, 1 mg/kg/day or more and 1 mg/kg/day or more, respectively, under the experimental conditions of this study.

  19. Protein-based peptide-bond formation by aminoacyl-tRNA protein transferase.

    PubMed

    Watanabe, Kazunori; Toh, Yukimatsu; Suto, Kyoko; Shimizu, Yoshihiro; Oka, Natsuhisa; Wada, Takeshi; Tomita, Kozo

    2007-10-18

    Eubacterial leucyl/phenylalanyl-tRNA protein transferase (LF-transferase) catalyses peptide-bond formation by using Leu-tRNA(Leu) (or Phe-tRNA(Phe)) and an amino-terminal Arg (or Lys) of a protein, as donor and acceptor substrates, respectively. However, the catalytic mechanism of peptide-bond formation by LF-transferase remained obscure. Here we determine the structures of complexes of LF-transferase and phenylalanyl adenosine, with and without a short peptide bearing an N-terminal Arg. Combining the two separate structures into one structure as well as mutation studies reveal the mechanism for peptide-bond formation by LF-transferase. The electron relay from Asp 186 to Gln 188 helps Gln 188 to attract a proton from the alpha-amino group of the N-terminal Arg of the acceptor peptide. This generates the attacking nucleophile for the carbonyl carbon of the aminoacyl bond of the aminoacyl-tRNA, thus facilitating peptide-bond formation. The protein-based mechanism for peptide-bond formation by LF-transferase is similar to the reverse reaction of the acylation step observed in the peptide hydrolysis reaction by serine proteases.

  20. The determination of tRNALeu recognition nucleotides for Escherichia coli L/F transferase

    PubMed Central

    Fung, Angela Wai Shan; Leung, Charles Chung Yun; Fahlman, Richard Peter

    2014-01-01

    Escherichia coli leucyl/phenylalanyl-tRNA protein transferase catalyzes the tRNA-dependent post-translational addition of amino acids onto the N-terminus of a protein polypeptide substrate. Based on biochemical and structural studies, the current tRNA recognition model by L/F transferase involves the identity of the 3′ aminoacyl adenosine and the sequence-independent docking of the D-stem of an aminoacyl-tRNA to the positively charged cluster on L/F transferase. However, this model does not explain the isoacceptor preference observed 40 yr ago. Using in vitro-transcribed tRNA and quantitative MALDI-ToF MS enzyme activity assays, we have confirmed that, indeed, there is a strong preference for the most abundant leucyl-tRNA, tRNALeu (anticodon 5′-CAG-3′) isoacceptor for L/F transferase activity. We further investigate the molecular mechanism for this preference using hybrid tRNA constructs. We identified two independent sequence elements in the acceptor stem of tRNALeu (CAG)—a G3:C70 base pair and a set of 4 nt (C72, A4:U69, C68)—that are important for the optimal binding and catalysis by L/F transferase. This maps a more specific, sequence-dependent tRNA recognition model of L/F transferase than previously proposed. PMID:24935875

  1. Oral biopsy: oral pathologist's perspective.

    PubMed

    Kumaraswamy, K L; Vidhya, M; Rao, Prasanna Kumar; Mukunda, Archana

    2012-01-01

    Many oral lesions may need to be diagnosed by removing a sample of tissue from the oral cavity. Biopsy is widely used in the medical field, but the practice is not quite widespread in dental practice. As oral pathologists, we have found many artifacts in the tissue specimen because of poor biopsy technique or handling, which has led to diagnostic pitfalls and misery to both the patient and the clinician. This article aims at alerting the clinicians about the clinical faults arising preoperatively, intraoperatively and postoperatively while dealing with oral biopsy that may affect the histological assessment of the tissue and, therefore, the diagnosis. It also reviews the different techniques, precautions and special considerations necessary for specific lesions.

  2. Phosphonocarboxylates Inhibit the Second Geranylgeranyl Addition by Rab Geranylgeranyl Transferase*

    PubMed Central

    Baron, Rudi A.; Tavaré, Richard; Figueiredo, Ana C.; Błażewska, Katarzyna M.; Kashemirov, Boris A.; McKenna, Charles E.; Ebetino, Frank H.; Taylor, Adam; Rogers, Michael J.; Coxon, Fraser P.; Seabra, Miguel C.

    2009-01-01

    Rab geranylgeranyl transferase (RGGT) catalyzes the post-translational geranylgeranyl (GG) modification of (usually) two C-terminal cysteines in Rab GTPases. Here we studied the mechanism of the Rab geranylgeranylation reaction by bisphosphonate analogs in which one phosphonate group is replaced by a carboxylate (phosphonocarboxylate, PC). The phosphonocarboxylates used were 3-PEHPC, which was previously reported, and 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid ((+)-3-IPEHPC), a >25-fold more potent related compound as measured by both IC50 and Ki.(+)-3-IPEHPC behaves as a mixed-type inhibitor with respect to GG pyrophosphate (GGPP) and an uncompetitive inhibitor with respect to Rab substrates. We propose that phosphonocarboxylates prevent only the second GG transfer onto Rabs based on the following evidence. First, geranylgeranylation of Rab proteins ending with a single cysteine motif such as CAAX, is not affected by the inhibitors, either in vitro or in vivo. Second, the addition of an -AAX sequence onto Rab-CC proteins protects the substrate from inhibition by the inhibitors. Third, we demonstrate directly that in the presence of (+)-3-IPEHPC, Rab-CC and Rab-CXC proteins are modified by only a single GG addition. The presence of (+)-3-IPEHPC resulted in a preference for the Rab N-terminal cysteine to be modified first, suggesting an order of cysteine geranylgeranylation in RGGT catalysis. Our results further suggest that the inhibitor binds to a site distinct from the GGPP-binding site on RGGT. We suggest that phosphonocarboxylate inhibitors bind to a GG-cysteine binding site adjacent to the active site, which is necessary to align the mono-GG-Rab for the second GG addition. These inhibitors may represent a novel therapeutic approach in Rab-mediated diseases. PMID:19074143

  3. Molecular characterization of a glutathione transferase from Pinus tabulaeformis (Pinaceae).

    PubMed

    Zeng, Qing-Yin; Lu, Hai; Wang, Xiao-Ru

    2005-05-01

    Glutathione transferases (GSTs) play important roles in stress tolerance and detoxification metabolism in plants. To date, studies on GSTs in higher plants have focused largely on agricultural plants. In contrast, there is virtually no information on the molecular characteristics of GSTs in gymnosperms. The present study reports for the first time the cloning, expression and characteristics of a GST gene (PtGSTU1) from a pine, Pinus tabulaeformis, which is widely distributed from northern to central China covering cold temperate and drought regions. The PtGSTU1 gene encodes a protein of 228 amino acid residues with a calculated molecular mass of 26.37 kDa. Reverse transcription PCR revealed that PtGSTU1 was expressed in different tissues, both above and below ground, of P. tabulaeformis. The over-expressed recombinant PtGSTU1 showed high activity towards the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl). Kinetic analysis with respect to CDNB as substrate revealed a Km of 0.47 mM and Vmax of 169.1 micromol/min per mg of protein. The recombinant PtGSTU1 retained more than 60% of its maximum enzymatic activity from 15 degrees C to 45 degrees C with a broad optimum Tm range of 25 degrees C - 35 degrees C. The enzyme had a maximum activity at approximately pH 8.5 - 9.0. Site-directed mutagenesis revealed that Ser13 in the N-terminal domain is a critical catalytic residue, responsible for stabilisation of the thiolate anion of enzyme-bound glutathione. Based on comparative analyses of its amino acid sequence, phylogeny and predicted three-dimensional structure, the PtGSTU1 should be classified as a tau class GST.

  4. Synthesis of ATP derivatives of compounds of the mevalonate pathway (isopentenyl di- and triphosphate; geranyl di- and triphosphate, farnesyl di- and triphosphate, and dimethylallyl diphosphate) catalyzed by T4 RNA ligase, T4 DNA ligase and other ligases Potential relationship with the effect of bisphosphonates on osteoclasts.

    PubMed

    Sillero, Maria A Günther; de Diego, Anabel; Tavares, Janeth E F; Silva, Joana A D Catanho da; Pérez-Zúñiga, Francisco J; Sillero, Antonio

    2009-08-15

    Compounds of the mevalonate pathway containing a terminal di- or triphosphate (mev-PP or mev-PPP) were tested as substrates of several enzyme ligases (T4 RNA ligase, T4 DNA ligase, firefly luciferase and other ligases) for the synthesis of ATP derivatives of the mev-pppA or mev-ppppA type. T4 RNA ligase, in the presence of ATP and the substrates: geranyl, farnesyl or isopentenyl triphosphates, and geranyl, farnesyl, dimethylallyl or isopentenyl diphosphates, all at 0.3 mM concentration, catalyzed the synthesis of the corresponding ATP derivatives at a relative rate of activity of: 7.6+/-1.4 mU/mg or 100%; 39%; 42%; 24%; 18%; 12% and 6%, respectively. Inhibition (%) of the synthesis by excess of substrate (0.8 mM vs. 0.3 mM) was observed with farnesyl diphosphate (99%); farnesyl triphosphate (96%) and geranyl triphosphate (32%). V(max), K(m), K(cat) and K(cat)/K(m) values were also determined. The K(cat)/K(m) values calculated were for: farnesyl triphosphate, 166; geranyl triphosphate, 52.2; farnesyl diphosphate, 12.1; geranyl diphosphate, 8.6; isopentenyl triphosphate, 6.7; dimethylallyl diphosphate, 3.1 and isopentenyl diphosphate, 0.9. Similar results were obtained with T4 DNA ligase. The above-mentioned compounds were also substrates of firefly luciferase synthesizing the mev-pppA or mev-ppppA derivatives. In our hands, neither the acyl- or acetyl-CoA synthetases nor the ubiquiting activating enzyme (E1) catalyzed the synthesis of ATP derivatives of these compounds. The results here presented could be related with the mechanism of action of bisphosphonates on osteoclasts or tumor cells.

  5. Squid glutathione S-transferase. Relationships with other glutathione S-transferases and S-crystallins of cephalopods.

    PubMed

    Tomarev, S I; Zinovieva, R D; Guo, K; Piatigorsky, J

    1993-02-25

    Glutathione S-transferase (GST, EC 2.5.1.18) was purified from the digestive gland of the squid Ommastrephes sloani pacificus. It had high enzymatic activity for the 1-chloro-2,4-dinitrobenzene substrate and was composed of a major and a minor polypeptide band, both with molecular masses near 25 kDa on SDS-polyacrylamide gels. GST cDNA clones were derived from the digestive gland mRNA. The deduced GSTs of the longest cDNAs (pGST5 and pGST11) containing the entire coding sequence have a molecular mass near 23 kDa. Sequence comparisons showed that the squid GST is 42-44% identical to both squid and octopus S-crystallins (the major proteins of the lens), 32-34% identical to class pi and 29-32% identical to class alpha GSTs of vertebrates, and 19-23% identical to other GSTs of vertebrates and insects. Northern blot hybridization revealed that GST mRNAs were much more abundant in the digestive gland than in the testis, mantle, or lens. Analysis of a squid GST gene indicated that it has an exon-intron structure similar to that of the vertebrate class pi GST gene. An apparently novel repetitive element was identified in the 5'-flanking sequence of the squid GST gene. Our results suggest that multiple duplications of an ancestral GST gene gave rise to a family of enzymatically inactive crystallins specialized for lens refraction and one (or two) active GST enzyme expressed preferentially, but not exclusively, in the digestive gland in squids. This differs from the innovation of refractive function from a metabolic enzyme by increased expression in the lens with minimal or no gene duplication, as occurred among the enzyme-crystallins of vertebrates.

  6. Normal Oral Flora and the Oral Ecosystem.

    PubMed

    Samaranayake, Lakshman; Matsubara, Victor H

    2017-04-01

    The oral ecosystem comprises the oral flora, so-called oral microbiome, the different anatomic microniches of the oral cavity, and its bathing fluid, saliva. The oral microbiome comprises a group of organisms and includes bacteria, archaea, fungi, protozoa, and viruses. The oral microbiome exists suspended in saliva as planktonic phase organisms or attached to oral surfaces as a plaque biofilm. Homeostasis of the plaque biofilm and its symbiotic relationship with the host is critical for oral health. Disequilibrium or dysbiosis within the plaque biofilms is the initiating event that leads to major oral diseases, such as caries and periodontal disease.

  7. Oral myiasis.

    PubMed

    Pereira, Treville; Tamgadge, Avinash P; Chande, Mayura S; Bhalerao, Sudhir; Tamgadge, Sandhya

    2010-10-01

    Myiasis is a relatively rare condition arising from the invasion of body tissues or cavities of living animals or humans by maggots or larvae of certain species of flies. It is an uncommon clinical condition, being more frequent in underdeveloped countries and hot climate regions, and is associated with poor hygiene, suppurative oral lesions; alcoholism and senility. Its diagnosis is made basically by the presence of larvae. The present article reports a case of oral myiasis involving 20 larvae in a patient with neurological deficiency.

  8. Oral myiasis

    PubMed Central

    Pereira, Treville; Tamgadge, Avinash P.; Chande, Mayura S.; Bhalerao, Sudhir; Tamgadge, Sandhya

    2010-01-01

    Myiasis is a relatively rare condition arising from the invasion of body tissues or cavities of living animals or humans by maggots or larvae of certain species of flies. It is an uncommon clinical condition, being more frequent in underdeveloped countries and hot climate regions, and is associated with poor hygiene, suppurative oral lesions; alcoholism and senility. Its diagnosis is made basically by the presence of larvae. The present article reports a case of oral myiasis involving 20 larvae in a patient with neurological deficiency. PMID:22114438

  9. Kinetic mechanism of octopus hepatopancreatic glutathione transferase in reverse micelles.

    PubMed Central

    Tang, S S; Chang, G G

    1996-01-01

    Octopus glutathione transferase (GST) was enzymically active in aerosol-OT [sodium bis-(2-ethylhexyl)sulphosuccinate]/iso-octane reverse micelles albeit with lowered catalytic constant (kcat). The enzyme reaction rate was found to be dependent on the [H2O]/[surfactant] ratio (omega(o)) of the system with maximum rate observed at omega(o) 13.88, which corresponded to vesicles with a core volume of 64 nm3. According to the physical examinations, a vesicle of this size is barely large enough to accommodate a monomeric enzyme subunit. Dissociation of the enzyme in reverse micelles was confirmed by cross-linking of the associated subunits with glutaraldehyde and separation of the monomers and dimers with electrophoresis in the presence of SDS. The kinetic properties of the enzyme were investigated by steady-state kinetic analysis. Both GSH and 1-chloro-2,4-dinitrobenzene (CDNB) showed substrate inhibition and the Michaelis constant for CDNB was increased by 36-fold to 11.05 mM in reverse micelles. Results on the initial-velocity and product-inhibition studies indicate that the octopus GST conforms to a steady-state sequential random Bi Bi mechanism. The results from a log kcat versus pH plot suggest that amino acid residues with pKa values of 6.56 0.07 and 8.81 0.17 should be deprotonated to give optimum catalytic function. In contrast, the amino acid residue with a pKa value of 9.69 0.16 in aqueous solution had to be protonated for the reaction to proceed. We propose that the pKa1 (6.56) is that for the enzyme-bound GSH, which has a pKa value lowered by 1.40-1.54 pH units compared with that of free GSH in reverse micelles. The most probable candidate for the observed pKa2 (8.81) is Tyr7 of GST. The pKa of Tyr7 is 0.88 pH unit lower than that in aqueous solution and is about 2 pH units below the normal tyrosine. This tyrosyl residue may act as a base catalyst facilitating the dissociation of enzyme-bound GSH. The possible interaction of GST with plasma membrane in vivo

  10. Kinetic mechanism of octopus hepatopancreatic glutathione transferase in reverse micelles.

    PubMed

    Tang, S S; Chang, G G

    1996-04-15

    Octopus glutathione transferase (GST) was enzymically active in aerosol-OT [sodium bis-(2-ethylhexyl)sulphosuccinate]/iso-octane reverse micelles albeit with lowered catalytic constant (kcat). The enzyme reaction rate was found to be dependent on the [H2O]/[surfactant] ratio (omega(o)) of the system with maximum rate observed at omega(o) 13.88, which corresponded to vesicles with a core volume of 64 nm3. According to the physical examinations, a vesicle of this size is barely large enough to accommodate a monomeric enzyme subunit. Dissociation of the enzyme in reverse micelles was confirmed by cross-linking of the associated subunits with glutaraldehyde and separation of the monomers and dimers with electrophoresis in the presence of SDS. The kinetic properties of the enzyme were investigated by steady-state kinetic analysis. Both GSH and 1-chloro-2,4-dinitrobenzene (CDNB) showed substrate inhibition and the Michaelis constant for CDNB was increased by 36-fold to 11.05 mM in reverse micelles. Results on the initial-velocity and product-inhibition studies indicate that the octopus GST conforms to a steady-state sequential random Bi Bi mechanism. The results from a log kcat versus pH plot suggest that amino acid residues with pKa values of 6.56 0.07 and 8.81 0.17 should be deprotonated to give optimum catalytic function. In contrast, the amino acid residue with a pKa value of 9.69 0.16 in aqueous solution had to be protonated for the reaction to proceed. We propose that the pKa1 (6.56) is that for the enzyme-bound GSH, which has a pKa value lowered by 1.40-1.54 pH units compared with that of free GSH in reverse micelles. The most probable candidate for the observed pKa2 (8.81) is Tyr7 of GST. The pKa of Tyr7 is 0.88 pH unit lower than that in aqueous solution and is about 2 pH units below the normal tyrosine. This tyrosyl residue may act as a base catalyst facilitating the dissociation of enzyme-bound GSH. The possible interaction of GST with plasma membrane in vivo

  11. Expression of glutathione S-transferase during rat liver development.

    PubMed Central

    Tee, L B; Gilmore, K S; Meyer, D J; Ketterer, B; Vandenberghe, Y; Yeoh, G C

    1992-01-01

    The ontogeny of rat liver glutathione S-transferase (EC 2.5.1.18) (GSTs) during foetal and postnatal development was investigated. The GSTs are dimers, the subunits of which belong to three multigene families, Alpha (subunits 1, 2, 8 and 10), Mu (subunits 3, 4, 6, 9 and 11) and Pi (subunit 7) [Mannervik, Alin, Guthenberg, Jennsson, Tahir, Warholm & Jörnvall (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 7202-7206; Kispert, Meyer, Lalor, Coles & Ketterer (1989) Biochem. J. 260, 789-793]. There is considerable structural homology within each gene family, with the result that whereas reverse-phase h.p.l.c. successfully differentiates individual subunits, immunocytochemical and Northern-blotting analyses may only differentiate families. Enzymic activity, h.p.l.c. and Northern blotting indicated that expression of GST increased from very low levels at 12 days of foetal growth to substantial amounts at day 21. At birth, GST concentrations underwent a dramatic decline and remained low until 5-10 days post partum, after which they increased to adult levels. During the period under study, GST subunits underwent differential expression. The Mu family had a lower level of expression than the Alpha family, and, within the Alpha family, subunit 1 was more dominant in the adult than the foetus. Subunit 2 is the major form in the foetus. Most noteworthy were subunits 7 and 10, which were prominent in the foetus, but present at low levels post partum. Immunocytochemical analysis of the 17-day foetal and newborn rat livers showed marked differences in the distribution of GSTs in hepatocytes. In the 17-day foetal liver Pi greater than Alpha greater than Mu whereas in the newborns Alpha greater than Mu much greater than Pi. Erythropoietic cells were not stained for any of the three GST families. Steady-state mRNA concentrations in the foetus correlated with the relative transcription of the Alpha, Mu and Pi class genes. However, in those genes expressed post partum, namely the Alpha and

  12. Induction of Glutathione S-Transferase Isozymes in Sorghum by Herbicide Antidotes 1

    PubMed Central

    Dean, John V.; Gronwald, John W.; Eberlein, Charlotte V.

    1990-01-01

    Certain chemicals referred to as herbicide antidotes protect sorghum from injury by chloroacetanilide herbicides such as metolachlor. The effect of herbicide antidotes on the glutathione S-transferase isozyme complement of etiolated sorghum (Sorghum bicolor [L.] Moench) shoots was examined. Elution profiles of glutathione S-transferase isozymes from untreated and antidote-treated seedlings were generated by fast protein liquid chromatography utilizing an anion exchange (Mono Q) column. In untreated seedlings, there were two glutathione S-transferase isozymes, a major isozyme which exhibited activity toward 1-chloro-2,4-dinitrobenzene and a minor isozyme which exhibited activity toward metolachlor. Treating sorghum seedlings with various antidotes (flurazole, oxabetrinil, CGA-133205, naphthalic anhydride, dichlormid) resulted in the appearance of four to five additional glutathione S-transferase isozymes (de-pending on the particular antidote) which exhibited activity toward metolachlor as a substrate and little or no activity with 1-chloro-2,4-dinitrobenzene. Treating etiolated sorghum shoots with metolachlor was also found to induce at least four isozymes which exhibited activity toward the herbicide. An increase in glutathione S-transferase activity, measured with metolachlor as substrate, was detected within 4 h after treatment with 30 micromolar oxabetrinil, but 36 hours were required for maximum expression of activity. Addition of either the transcription inhibitor cordycepin or the translation inhibitor cycloheximide inhibited the appearance of glutathione S-transferase activity measured with metolachlor as substrate. The results are consistent with the hypothesis that antidotes confer protection against metolachlor injury in sorghum by inducing the de novo synthesis of glutathione S-transferase isozymes which catalyze the detoxification of the herbicide. PMID:16667299

  13. Oral Cancer

    MedlinePlus

    ... Cancer Institute, components of the National Institutes of Health in Bethesda, Md. For more copies contact: National Institute of Dental and Craniofacial Research National Oral Health Information Clearinghouse 1 NOHIC Way Bethesda, MD 20892-3500 1–866–232–4528 www. nidcr. ...

  14. Oral Tumours

    PubMed Central

    Lecavalier, D.R.; Main, J.H.P.

    1988-01-01

    The authors of this article review briefly the anatomy of the oral soft tissues and describe the more common benign and malignant tumours of the mouth, giving emphasis to their clinical features. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8 PMID:21253197

  15. Oral medications.

    PubMed

    Albretsen, Jay C

    2002-03-01

    Many medications are available today by prescription or in over-the-counter preparations. This article reviews the pharmacokinetics, mechanism of action, toxicity, clinical signs, and management procedures necessary for some oral medications. The medications reviewed include selective serotonin reuptake inhibitors, benzodiazepines, amphetamines or amphetamine like drugs, carprofen, cyclooxygenase-2 inhibitors, pseudoephedrine, calcium channel blockers, and baclofen.

  16. The ubiquitin C-terminal hydrolase L1 (UCH-L1) C terminus plays a key role in protein stability, but its farnesylation is not required for membrane association in primary neurons.

    PubMed

    Bishop, Paul; Rubin, Philip; Thomson, Andrew R; Rocca, Dan; Henley, Jeremy M

    2014-12-26

    Ubiquitin C-terminal hydrolase L1 (UCH-L1) is a deubiquitinating enzyme that is highly expressed in neurons. A possible role for UCH-L1 in neurodegeneration has been highlighted because of its presence in Lewy bodies associated with Parkinson disease and neurofibrillary tangles observed in Alzheimer disease. UCH-L1 exists in two forms in neurons, a soluble cytoplasmic form (UCH-L1(C)) and a membrane-associated form (UCH-L1(M)). Alzheimer brains show reduced levels of soluble UCH-L1(C) correlating with the formation of UCH-L1-immunoreactive tau tangles, whereas UCH-L1(M) has been implicated in α-synuclein dysfunction. Given these reports of divergent roles, we investigated the properties of UCH-L1 membrane association. Surprisingly, our results indicate that UCH-L1 does not partition to the membrane in the cultured cell lines we tested. Furthermore, in primary cultured neurons, a proportion of UCH-L1(M) does partition to the membrane, but, contrary to a previous report, this does not require farnesylation. Deletion of the four C-terminal residues caused the loss of protein solubility, abrogation of substrate binding, increased cell death, and an abnormal intracellular distribution, consistent with protein dysfunction and aggregation. These data indicate that UCH-L1 is differently processed in neurons compared with clonal cell lines and that farnesylation does not account for the membrane association in neurons.

  17. Induction of the cholesterol metabolic pathway regulates the farnesylation of RAS in embryonic chick heart cells: a new role for ras in regulating the expression of muscarinic receptors and G proteins.

    PubMed Central

    Gadbut, A P; Wu, L; Tang, D; Papageorge, A; Watson, J A; Galper, J B

    1997-01-01

    We propose a novel mechanism for the regulation of the processing of Ras and demonstrate a new function for Ras in regulating the expression of cardiac autonomic receptors and their associated G proteins. We have demonstrated previously that induction of endogenous cholesterol synthesis in cultured cardiac myocytes resulted in a coordinated increase in expression of muscarinic receptors, the G protein alpha-subunit, G-alphai2, and the inward rectifying K+ channel, GIRK1. These changes in gene expression were associated with a marked increase in the response of heart cells to parasympathetic stimulation. In this study, we demonstrate that the induction of the cholesterol metabolic pathway regulates Ras processing and that Ras regulates expression of G-alphai2. We show that in primary cultured myocytes most of the RAS is localized to the cytoplasm in an unfarnesylated form. Induction of the cholesterol metabolic pathway results in increased farnesylation and membrane association of RAS. Studies of Ras mutants expressed in cultured heart cells demonstrate that activation of Ras by induction of the cholesterol metabolic pathway results in increased expression of G-alphai2 mRNA. Hence farnesylation of Ras is a regulatable process that plays a novel role in the control of second messenger pathways. PMID:9405354

  18. Kinetic independence of the subunits of cytosolic glutathione transferase from the rat.

    PubMed Central

    Danielson, U H; Mannervik, B

    1985-01-01

    The steady-state kinetics of the dimeric glutathione transferases deviate from Michaelis-Menten kinetics, but have hyperbolic binding isotherms for substrates and products of the enzymic reaction. The possibility of subunit interactions during catalysis as an explanation for the rate behaviour was investigated by use of rat isoenzymes composed of subunits 1, 2, 3 and 4, which have distinct substrate specificities. The kinetic parameter kcat./Km was determined with 1-chloro-2,4-dinitrobenzene, 4-hydroxyalk-2-enals, ethacrynic acid and trans-4-phenylbut-3-en-2-one as electrophilic substrates for six isoenzymes: rat glutathione transferases 1-1, 1-2, 2-2, 3-3, 3-4 and 4-4. It was found that the kcat./Km values for the heterodimeric transferases 1-2 and 3-4 could be predicted from the kcat./Km values of the corresponding homodimers. Likewise, the initial velocities determined with transferases 3-3, 3-4 and 4-4 at different degrees of saturation with glutathione and 1-chloro-2,4-dinitrobenzene demonstrated that the kinetic properties of the subunits are additive. These results show that the subunits of glutathione transferase are kinetically independent. PMID:4062896

  19. Modulation of human glutathione s-transferases by polyphenon e intervention.

    PubMed

    Chow, H-H Sherry; Hakim, Iman A; Vining, Donna R; Crowell, James A; Tome, Margaret E; Ranger-Moore, James; Cordova, Catherine A; Mikhael, Dalia M; Briehl, Margaret M; Alberts, David S

    2007-08-01

    Green tea consumption has been associated with decreased risk of certain types of cancers in humans. Induction of detoxification enzymes has been suggested as one of the biochemical mechanisms responsible for the cancer-preventive effect of green tea. We conducted this clinical study to determine the effect of repeated green tea polyphenol administration on a major group of detoxification enzymes, glutathione S-transferases (GST). A total of 42 healthy volunteers underwent a 4-week washout period by refraining from tea or tea-related products. At the end of the washout period, a fasting blood sample was collected, and plasma and lymphocytes were isolated for assessment of GST activity and level. Following the baseline evaluation, study participants underwent 4 weeks of green tea polyphenol intervention in the form of a standardized Polyphenon E preparation at a dose that contains 800 mg epigallocatechin gallate (EGCG) once a day. Polyphenon E was taken on an empty stomach to optimize the oral bioavailability of EGCG. Upon completion of the intervention, samples were collected for postintervention GST assessment. Four weeks of Polyphenon E intervention enhanced the GST activity in blood lymphocytes from 30.7 +/- 12.2 to 35.1 +/- 14.3 nmol/min/mg protein, P = 0.058. Analysis based on baseline activity showed that a statistically significant increase (80%, P = 0.004) in GST activity was observed in individuals with baseline activity in the lowest tertile, whereas a statistically significant decrease (20%, P = 0.02) in GST activity was observed in the highest tertile. In addition, Polyphenon E intervention significantly increased the GST-pi level in blood lymphocytes from 2,252.9 +/- 734.2 to 2,634.4 +/- 1,138.3 ng/mg protein, P = 0.035. Analysis based on baseline level showed that this increase was only significant (P = 0.003) in individuals with baseline level in the lowest tertile, with a mean increase of 80%. Repeated Polyphenon E administration had minimal effects

  20. Oral candidiasis

    PubMed Central

    Akpan, A; Morgan, R

    2002-01-01

    Oral candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of Candida species, the commonest being Candida albicans. The incidence varies depending on age and certain predisposing factors. There are three broad groupings consisting of acute candidiasis, chronic candidiasis, and angular cheilitis. Risk factors include impaired salivary gland function, drugs, dentures, high carbohydrate diet, and extremes of life, smoking, diabetes mellitus, Cushing's syndrome, malignancies, and immunosuppressive conditions. Management involves taking a history, an examination, and appropriate antifungal treatment with a few requiring samples to be taken for laboratory analysis. In certain high risk groups antifungal prophylaxis reduces the incidence and severity of infections. The prognosis is good in the great majority of cases. PMID:12185216

  1. Separation of glutathione transferase subunits from Proteus vulgaris by two-dimensional gel electrophoresis.

    PubMed

    Hong, Giaming; Chien, Yi-Chih; Chien, Cheng-I

    2003-10-01

    Cytosolic glutathione transferases of Proteus vulgaris were purified by affinity chromatography and characterized by two-dimensional gel electrophoresis. Four different subunits were identified, and each subunit contained a different molecular mass, ranging from 26.2 kDa to 28.5 kDa; a different pI value, ranging from 8.2 to 9.4; and a different amount of protein fraction, ranging from 10% to 56%. All four subunits existed as basic proteins (pI > 7.0). From these results, we concluded that multiple forms of glutathione transferase enzymes existed in Proteus vulgaris, and four different glutathione transferase subunits were separated by 2-D gel electrophoresis.

  2. Oral contraceptives.

    PubMed

    Oesterheld, Jessica R; Cozza, Kelly; Sandson, Neil B

    2008-01-01

    Nearly 50 years ago, the introduction of Enovid (norethynodrel 10 microg and mestranol 150 microg), which provided convenient and reliable contraception, revolutionized birth control. Reports of interactions between oral contraceptives (OCs) and other drugs began to trickle into the literature. At first, these drug interactions appeared to be random and unrelated. Increased understanding of P450 enzymes and phase II reactions of sulfation and glucuronidation has permitted preliminary categorization and assessment of the clinical relevance of these drug interactions.

  3. Fusarium moniliforme extract fed before a single dose of diethylnitrosamine increases the numbers of placental glutathione S-transferase positive hepatocytes in rat liver

    SciTech Connect

    Lebepe, S.; Hendrich, S. )

    1991-03-11

    The carcinogenic potential of an alcohol:water (1:1) extract of Fusarium moniliforme (FUSX), containing 20 ppm fumonisin B{sub 1} was assayed. Groups of six 5-week-old female F344/N rats were fed a semipurified diet, with and without FUSX. A dose of initiating agent, diethylnitrosamine, was given orally. Placental glutathione S-transferase-positive (PGST(+)) hepatocytes were detected by immunohistochemistry and counted on 5 frozen hepatic sections/rat, as an endpoint to assess early stages of carcinogenesis. FUSX had significant co-initiating activity. Fusarium moniliforme infection of feed has been shown to promote hepatocarcinogenesis, and may pose a cocarcinogenic risk even during short-term, low-level exposure.

  4. Mapping of amino acid substitutions conferring herbicide resistance in wheat glutathione transferase.

    PubMed

    Govindarajan, Sridhar; Mannervik, Bengt; Silverman, Joshua A; Wright, Kathy; Regitsky, Drew; Hegazy, Usama; Purcell, Thomas J; Welch, Mark; Minshull, Jeremy; Gustafsson, Claes

    2015-03-20

    We have used design of experiments (DOE) and systematic variance to efficiently explore glutathione transferase substrate specificities caused by amino acid substitutions. Amino acid substitutions selected using phylogenetic analysis were synthetically combined using a DOE design to create an information-rich set of gene variants, termed infologs. We used machine learning to identify and quantify protein sequence-function relationships against 14 different substrates. The resulting models were quantitative and predictive, serving as a guide for engineering of glutathione transferase activity toward a diverse set of herbicides. Predictive quantitative models like those presented here have broad applicability for bioengineering.

  5. The Making of a Sweet Modification: Structure and Function of O-GlcNAc Transferase*

    PubMed Central

    Janetzko, John; Walker, Suzanne

    2014-01-01

    O-GlcNAc transferase is an essential mammalian enzyme responsible for transferring a single GlcNAc moiety from UDP-GlcNAc to specific serine/threonine residues of hundreds of nuclear and cytoplasmic proteins. This modification is dynamic and has been implicated in numerous signaling pathways. An unexpected second function for O-GlcNAc transferase as a protease involved in cleaving the epigenetic regulator HCF-1 has also been reported. Recent structural and biochemical studies that provide insight into the mechanism of glycosylation and HCF-1 cleavage will be described, with outstanding questions highlighted. PMID:25336649

  6. The separation of glutathione transferase subunits by using reverse-phase high-pressure liquid chromatography.

    PubMed Central

    Ostlund Farrants, A K; Meyer, D J; Coles, B; Southan, C; Aitken, A; Johnson, P J; Ketterer, B

    1987-01-01

    A simple method is described for the separation and quantification of the subunits of GSH transferases present in rat tissue extracts. This method, involving GSH-agarose affinity chromatography followed by reverse-phase h.p.l.c., is rapid and sufficiently sensitive to measure 5 micrograms of each subunit in a mixture. Examples are given of its application to extracts of rat kidney, adrenal, testicular interstitial cells and seminiferous tubules. The analysis of seminiferous tubules indicates that the technique may be of value for the identification of novel subunits. Preliminary separations of subunits from human GSH transferases are also described. PMID:3663168

  7. Purification and Biochemical Characterization of Glutathione S-Transferase from Down Syndrome and Normal Children Erythrocytes: A Comparative Study

    ERIC Educational Resources Information Center

    Hamed, Ragaa R.; Maharem, Tahany M.; Abdel-Meguid, Nagwa; Sabry, Gilane M.; Abdalla, Abdel-Monem; Guneidy, Rasha A.

    2011-01-01

    Down syndrome (DS) is the phenotypic manifestation of trisomy 21. Our study was concerned with the characterization and purification of glutathione S-transferase enzyme (GST) from normal and Down syndrome (DS) erythrocytes to illustrate the difference in the role of this enzyme in the cell. Glutathione S-transferase and glutathione (GSH) was…

  8. Purification and Biochemical Characterization of Glutathione S-Transferase from Down Syndrome and Normal Children Erythrocytes: A Comparative Study

    ERIC Educational Resources Information Center

    Hamed, Ragaa R.; Maharem, Tahany M.; Abdel-Meguid, Nagwa; Sabry, Gilane M.; Abdalla, Abdel-Monem; Guneidy, Rasha A.

    2011-01-01

    Down syndrome (DS) is the phenotypic manifestation of trisomy 21. Our study was concerned with the characterization and purification of glutathione S-transferase enzyme (GST) from normal and Down syndrome (DS) erythrocytes to illustrate the difference in the role of this enzyme in the cell. Glutathione S-transferase and glutathione (GSH) was…

  9. Oral contraceptives.

    PubMed

    Maclennan, A H

    1987-12-01

    Over 60 million women use highly efficient and safe modern combined oral contraceptives (OCs) every day. A women who takes the oral contraceptive for 5 years before the age of 30 will actually live 12 days longer, although a woman taking the pill for the 1st time for 5 years after the age of 30 will have her life span reduced on the average by 80 days. OC related morbidity and mortality mostly occur in women over 35 who smoke. Combined low dose OCs are safe for women who do not smoke, at least to 45 years of age and probably to the menopause. The prescription of OCs is also safe to the young adolescent. The pill does not interfere with maturation of the hypothalamic-pituitary ovarian axis and does not increase the incidence of amenorrhoea, oligomenorrhoea or infertility in later life. Patients with contraindications to estrogen therapy are excluded from OC use (history of thromboembolism, major heart disease, liver disease, breast cancer). Low-dose (30-35 mcg estrogen-containing monophasic or triphasic) pills are recommended. Combined oral contraceptives contain either ethinyl estradiol (1.7 to 2 times more potent) or mestranol. After absorption the progestagens, norethisterone acetate, ethynodiol diacetate and lynoestrenol are all metabolized to norethisterone. The progestagen-only pill has about a 2% failure rate and poorer cycle control than the combined pill, but it lacks estrogenic, progestagenic and androgenic side effects. This pill is suitable for the lactating mother, for smokers over 35, for hypertensive patients, and for those with a history of thrombosis. The efficacy of the progestagen-only pill is restored in 3 days of pill taking. Postcoital contraception is an alternative: treatment can be given for at least 72 hours after intercourse. The Yuzpe method calls for the patient to take 2 combined oral contraceptive tablets containing levonorgestrel and ethinyl estradiol (Eugynon or Ovral) followed by a further 2 tablets 12 hours later. This regimen

  10. Oral contraceptives.

    PubMed

    Ellsworth, A J; Leversee, J H

    1990-09-01

    Management of oral contraception requires an understanding of the relationships between the method's effectiveness, noncontraceptive benefits, and hormonal adverse effects. The new multiphasic combinations or OCs containing 35 micrograms of ethinyl estradiol and 0.5-1.0 mg of norethindrone or equivalent result in a maximum combination of efficacy and safety for the patient with minimal annoying problems for the patient and the prescriber. Patient education regarding early warning symptoms of adverse effects, breakthrough bleeding, and lack of withdrawal bleeding adds an additional margin of safety and reduces patient questions and uncertainties.

  11. GSTM1 null polymorphism prevalence in tobacco users, oral leukoplakia and oral squamous cell carcinoma patients in South Indian population: A polymerase chain reaction study.

    PubMed

    Tanwar, Renu; Iyengar, Asha R; Nagesh, K S; Patil, Seema; Subhash, B V

    2016-01-01

    Tobacco abuse is a well-known risk factor for potentially malignant disorders as well as oral squamous cell carcinoma. Factors that influence tobacco-exposed individuals developing a malignancy may include the combination of total tobacco exposure and genetic susceptibility. This study was undertaken to determine the prevalence of the glutathione S-transferase M1 (GSTM1) null polymorphism in oral leukoplakia and oral squamous cell carcinoma patients in South Indian population. This case-control study was conducted in hospital setting on South Indian population. About 280 subjects with history of tobacco use, oral leukoplakia, oral squamous cell carcinoma were included in this study. Three milliliter of blood was collected and transported under cold cycle and taken for evaluation of GSTM1 null polymorphism using multiplex polymerase chain reaction. On comparing the prevalence of GSTM1 null polymorphism among the group with subjects with habits and no oral lesions, oral leukoplakia, and oral squamous cell carcinoma, it was observed that there was a statistically significant association between GSTM1 null polymorphism and the different groups (P < 0.01). The lack of GSTM1 activity would make the oral tissues more susceptible to action of tobacco carcinogens and to the development of a high-grade level of dysplasia in oral leukoplakia and thereby increases the susceptibility of lesion to undergo malignant changes.

  12. Global deletion of glutathione S-Transferase A4 exacerbates developmental nonalcoholic steatohepatitis

    USDA-ARS?s Scientific Manuscript database

    We established a mouse model of developmental nonalcoholic steatohepatitis (NASH) by feeding a high polyunsaturated fat liquid diet to female glutathione-S-transferase 4-4 (Gsta4-/-)/peroxisome proliferator activated receptor a (Ppara-/-) double knockout 129/SvJ mice for 12 weeks from weaning. We us...

  13. Maize white seedling 3 results from disruption of homogentisate solanesyl transferase

    USDA-ARS?s Scientific Manuscript database

    Maize white seedling 3 (w3) has served as a model albino-seedling mutant since its discovery in 1923. We show here that the w3 phenotype is caused by disruptions in homogentisate solanesyl transferase (HST), an enzyme that catalyzes the committed step in plastoquinone-9 (PQ9) biosynthesis. This re...

  14. GLUTATHIONE S-TRANSFERASE THETA 1-1-DEPENDENT METABOLISM OF THE DISINFECTION BYPRODUCT BROMODICHLOROMETHANE

    EPA Science Inventory

    ABSTRACT
    Bromodichloromethane (BDCM), a prevalent drinking water disinfection by-product, was previously shown to be mutagenic in Salmonella expressing glutathione S-transferase (GST) theta 1-1 (GST T1-1). In the present study, in vitro experiments were performed to study the...

  15. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  16. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  17. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  18. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  19. 21 CFR 573.130 - Aminoglycoside 3′-phospho- transferase II.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... genetically modified cotton, oilseed rape, and tomatoes in accordance with the following prescribed conditions... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Aminoglycoside 3â²-phospho- transferase II. 573.130 Section 573.130 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND...

  20. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  1. 21 CFR 862.1315 - Galactose-1-phosphate uridyl transferase test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Galactose-1-phosphate uridyl transferase test system. 862.1315 Section 862.1315 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical...

  2. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  3. Polymorphism in the intron 20 of porcine O-linked N-acetylglucosamine transferase

    USDA-ARS?s Scientific Manuscript database

    Objective: O-linked N-acetylglucosamine (O-GlcNAc) transferase (OGT) catalyzes the addition of O-GlcNAc and GlcNAcylation has extensive crosstalk with phosphorylation to regulate signaling and transcription. Pig OGT is located near the region of chromosome X that affects follicle stimulating hormone...

  4. Insight into the carboxyl transferase domain mechanism of pyruvate carboxylase from Rhizobium etli†

    PubMed Central

    Zeczycki, Tonya N.; Maurice, Martin St.; Jitrapakdee, Sarawut; Wallace, John C.; Attwood, Paul V.; Cleland, W. Wallace

    2009-01-01

    The effects of mutations in the active site of the carboxyl transferase domain of R. etli pyruvate carboxylase have been determined for the forward reaction to form oxaloacetate, the reverse reaction to form MgATP, the oxamate-induced decarboxylation of oxaloacetate, the phosphorylation of MgADP by carbamoyl phosphate and the bicarbonate-dependent ATPase reaction. Additional studies with these mutants examined the effect of pyruvate and oxamate on the reactions of the biotin carboxylase domain. From these mutagenic studies, putative roles for catalytically relevant active site residues were assigned and a more accurate description of the mechanism of the carboxyl transferase domain is presented. The T882A mutant showed no catalytic activity for reactions involving the carboxyl transferase domain, but surprisingly showed a 7- and 3.5-fold increase in activity, as compared to the wild-type enzyme, for the ADP phosphorylation and bicarbonate-dependent ATPase reactions, respectively. Furthermore, the partial inhibition of the T882A catalyzed BC domain reactions by oxamate and pyruvate further supports the critical role of Thr882 in the proton transfer between biotin and pyruvate in the carboxyl transferase domain. The catalytic mechanism appears to involve the decarboxylation of carboxybiotin and proton removal from Thr882 by the resulting biotin enolate with either a concerted or subsequent transfer of a proton from pyruvate to Thr882. The resulting enolpyruvate then reacts with CO2 to form oxaloacetate and complete the reaction. PMID:19341298

  5. Plasmodium spp. membrane glutathione S-transferases: detoxification units and drug targets

    PubMed Central

    Lisewski, Andreas M.

    2014-01-01

    Membrane glutathione S-transferases from the class of membrane-associated proteins in eicosanoid and glutathione metabolism (MAPEG) form a superfamily of detoxification enzymes that catalyze the conjugation of reduced glutathione (GSH) to a broad spectrum of xenobiotics and hydrophobic electrophiles. Evolutionarily unrelated to the cytosolic glutathione S-transferases, they are found across bacterial and eukaryotic domains, for example in mammals, plants, fungi and bacteria in which significant levels of glutathione are maintained. Species of genus Plasmodium, the unicellular protozoa that are commonly known as malaria parasites, do actively support glutathione homeostasis and maintain its metabolism throughout their complex parasitic life cycle. In humans and in other mammals, the asexual intraerythrocytic stage of malaria, when the parasite feeds on hemoglobin, grows and eventually asexually replicates inside infected red blood cells (RBCs), is directly associated with host disease symptoms and during this critical stage GSH protects the host RBC and the parasite against oxidative stress from parasite-induced hemoglobin catabolism. In line with these observations, several GSH-dependent Plasmodium enzymes have been characterized including glutathione reductases, thioredoxins, glyoxalases, glutaredoxins and glutathione S-transferases (GSTs); furthermore, GSH itself have been found to associate spontaneously and to degrade free heme and its hydroxide, hematin, which are the main cytotoxic byproducts of hemoglobin catabolism. However, despite the apparent importance of glutathione metabolism for the parasite, no membrane associated glutathione S-transferases of genus Plasmodium have been previously described. We recently reported the first examples of MAPEG members among Plasmodium spp. PMID:28357217

  6. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  7. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  8. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  9. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  10. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  11. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alanine amino transferase (ALT/SGPT) test system. 862.1030 Section 862.1030 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  12. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  13. 21 CFR 862.1100 - Aspartate amino transferase (AST/SGOT) test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Aspartate amino transferase (AST/SGOT) test system. 862.1100 Section 862.1100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...

  14. Preliminary X-ray crystallographic analysis of glutathione transferase zeta 1 (GSTZ1a-1a)

    SciTech Connect

    Boone, Christopher D.; Zhong, Guo; Smeltz, Marci; James, Margaret O. McKenna, Robert

    2014-01-21

    Crystals of glutathione transferase zeta 1 were grown and shown to diffract X-rays to 3.1 Å resolution. They belonged to space group P1, with unit-cell parameters a = 42.0, b = 49.6, c = 54.6 Å, α = 82.9, β = 69.9, γ = 73.4°.

  15. GLUTATHIONE S-TRANSFERASE THETA 1-1-DEPENDENT METABOLISM OF THE DISINFECTION BYPRODUCT BROMODICHLOROMETHANE

    EPA Science Inventory

    ABSTRACT
    Bromodichloromethane (BDCM), a prevalent drinking water disinfection by-product, was previously shown to be mutagenic in Salmonella expressing glutathione S-transferase (GST) theta 1-1 (GST T1-1). In the present study, in vitro experiments were performed to study the...

  16. The TIP GROWTH DEFECTIVE1 S-acyl transferase regulates plant cell growth in Arabidopsis.

    PubMed

    Hemsley, Piers A; Kemp, Alison C; Grierson, Claire S

    2005-09-01

    TIP GROWTH DEFECTIVE1 (TIP1) of Arabidopsis thaliana affects cell growth throughout the plant and has a particularly strong effect on root hair growth. We have identified TIP1 by map-based cloning and complementation of the mutant phenotype. TIP1 encodes an ankyrin repeat protein with a DHHC Cys-rich domain that is expressed in roots, leaves, inflorescence stems, and floral tissue. Two homologues of TIP1 in yeast (Saccharomyces cerevisiae) and human (Homo sapiens) have been shown to have S-acyl transferase (also known as palmitoyl transferase) activity. S-acylation is a reversible hydrophobic protein modification that offers swift, flexible control of protein hydrophobicity and affects protein association with membranes, signal transduction, and vesicle trafficking within cells. We show that TIP1 binds the acyl group palmitate, that it can rescue the morphological, temperature sensitivity, and yeast casein kinase2 localization defects of the yeast S-acyl transferase mutant akr1Delta, and that inhibition of acylation in wild-type Arabidopsis roots reproduces the Tip1- mutant phenotype. Our results demonstrate that S-acylation is essential for normal plant cell growth and identify a plant S-acyl transferase, an essential research tool if we are to understand how this important, reversible lipid modification operates in plant cells.

  17. DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1

    EPA Science Inventory


    DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1. R A Pegram1 and M K Ross2. 2Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC; 1Pharmacokinetics Branch, NHEERL, ORD, United States Environmental Protection Ag...

  18. DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1

    EPA Science Inventory


    DNA BINDING POTENTIAL OF BROMODICHLOROMETHANE MEDIATED BY GLUTATHIONE S-TRANSFERASE THETA 1-1. R A Pegram1 and M K Ross2. 2Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC; 1Pharmacokinetics Branch, NHEERL, ORD, United States Environmental Protection Ag...

  19. Peptidyl transferase centre of bacterial ribosomes: substrate specificity and binding sites.

    PubMed Central

    Krayevsky, A A; Kukhanova, M K; Gottikh, B P

    1975-01-01

    A detailed scheme of the Peptidyl Transferase Centre of bacterial ribosomes is proposed by summarizing the literature data on the substrate specificity of the acceptor and donor sites. According to the proposed scheme only the elements of the donor and acceptor having a stable structure bind with the ribosome. The present paper proposes such main elements for the donor and acceptor. PMID:802510

  20. Functional dissection of the bipartite active site of the class I coenzyme A (CoA)-transferase succinyl-CoA:acetate CoA-transferase

    DOE PAGES

    Murphy, Jesse R.; Mullins, Elwood A.; Kappock, T. Joseph

    2016-05-23

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates <3 Å apart. Here in this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes andmore » orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analog dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analog of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. Finally, the ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA.« less

  1. Functional dissection of the bipartite active site of the class I coenzyme A (CoA)-transferase succinyl-CoA:acetate CoA-transferase

    SciTech Connect

    Murphy, Jesse R.; Mullins, Elwood A.; Kappock, T. Joseph

    2016-05-23

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates <3 Å apart. Here in this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analog dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analog of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. Finally, the ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA.

  2. Functional Dissection of the Bipartite Active Site of the Class I Coenzyme A (CoA)-Transferase Succinyl-CoA:Acetate CoA-Transferase

    PubMed Central

    Murphy, Jesse R.; Mullins, Elwood A.; Kappock, T. Joseph

    2016-01-01

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates <3 Å apart. In this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analog dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analog of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. The ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA. PMID:27242998

  3. Functional dissection of the bipartite active site of the class I coenzyme A (CoA)-transferase succinyl-CoA:acetate CoA-transferase

    NASA Astrophysics Data System (ADS)

    Murphy, Jesse; Mullins, Elwood; Kappock, T.

    2016-05-01

    Coenzyme A (CoA)-transferases catalyze the reversible transfer of CoA from acyl-CoA thioesters to free carboxylates. Class I CoA-transferases produce acylglutamyl anhydride intermediates that undergo attack by CoA thiolate on either the internal or external carbonyl carbon atoms, forming distinct tetrahedral intermediates less than 3 Å apart. In this study, crystal structures of succinyl-CoA:acetate CoA-transferase (AarC) from Acetobacter aceti are used to examine how the Asn347 carboxamide stabilizes the internal oxyanion intermediate. A structure of the active mutant AarC-N347A bound to CoA revealed both solvent replacement of the missing contact and displacement of the adjacent Glu294, indicating that Asn347 both polarizes and orients the essential glutamate. AarC was crystallized with the nonhydrolyzable acetyl-CoA (AcCoA) analogue dethiaacetyl-CoA (1a) in an attempt to trap a closed enzyme complex containing a stable analogue of the external oxyanion intermediate. One active site contained an acetylglutamyl anhydride adduct and truncated 1a, an unexpected result hinting at an unprecedented cleavage of the ketone moiety in 1a. Solution studies confirmed that 1a decomposition is accompanied by production of near-stoichiometric acetate, in a process that seems to depend on microbial contamination but not AarC. A crystal structure of AarC bound to the postulated 1a truncation product (2a) showed complete closure of one active site per dimer but no acetylglutamyl anhydride, even with acetate added. These findings suggest that an activated acetyl donor forms during 1a decomposition; a working hypothesis involving ketone oxidation is offered. The ability of 2a to induce full active site closure furthermore suggests that it subverts a system used to impede inappropriate active site closure on unacylated CoA.

  4. Oral Lichen Planus

    MedlinePlus

    Oral lichen planus Overview By Mayo Clinic Staff Oral lichen planus (LIE-kun PLAY-nus) is an ongoing (chronic) ... that affects mucous membranes inside your mouth. Oral lichen planus may appear as white, lacy patches; red, ...

  5. Cloning, expression and properties of porcine trachea UDP-galnac: polypeptide N-acetylgalactosaminyl transferase.

    PubMed

    Sangadala, Sreedhara; Swain, Ja Baris; McNear, Adrian; Mendicino, Joseph

    2004-11-01

    A UDP-GalNAc:polypeptide N-acetyl-galactosaminyl transferase which catalyses the transfer of GalNAc from UDP-GalNAc to serine and threonine residues in mucin polypeptide chains was purified to homogeneity from swine trachea epithelium (Mendicino J, Sangadala S: Mol Cell Biochem 185: 135-145, 1998). Peptides obtained by proteolysis of the purified enzyme were isolated, sequenced and used to prepare degenerate oligonucleotide primers. Amplified segments of a gene encoding GalNAc transferase were synthesised using the primers and a swine trachea epithelial cDNA library. Selected cDNA fragments were then used to screen the cDNA library, and a clone containing an open reading frame encoding 559 amino acids was isolated. The predicted amino acid sequence contains type II transmembrane region, three potential N-glycosylation sites as well as all of the isolated peptide sequences. The nucleotide sequence and predicted primary protein structure of the transferase were very similar to those of type T-1 GalNAc transferases. The isolated clone was transiently expressed in COS 7 cells and the recombinant enzyme, which contained an N-terminal hexa-histidine tag, was purified to homogeneity and its enzymatic properties were examined. The Vmax of the recombinant enzyme, 2.08 micromol/(min mg), was nearly the same as the native enzyme, 2.12 micromol/(min mg), when assayed with partially deglycosylated mucins as glycosyl acceptors. Both enzymes showed much higher activities when assayed with peptides prepared by limited acid hydrolysis of incompletely deglycosylated Cowper's gland, swine, and human respiratory mucins and tryptic peptides isolated from deglycosylated mucin polypeptide chains. However, as noted earlier (Mendicino J, Sangadala S: Mol Cell Biochem 185: 135-145, 1998), these enzymes showed very little activity with completely deglycosylated mucin polypeptide chains. When completely deglycosylated polypeptide chains were partially glycosylated by incubation with microsome

  6. Restoration of Hypoxanthine Phosphoribosyl Transferase Activity in Mouse 1R Cells After Fusion with Chick-Embryo Fibroblasts

    PubMed Central

    Bakay, Bohdan; Croce, Carlo M.; Koprowski, Hilary; Nyhan, William L.

    1973-01-01

    Fusion of the 1R mouse cell, which lacks activity of hypoxanthine phosphoribosyl transferase (EC 2.4.2.8), with chick-embryo fibroblasts yielded progeny cells that survived in hypoxanthine-aminopterin-thymidine selective medium. This property and the failure of the progeny to survive in 8-azaguanine indicated that hypoxanthine phosphoribosyl transferase activity was present. Electrophoretic analysis revealed that the enzyme was of mouse, not chick, origin. These observations are consistent with the operation of a regulator gene responsible for the absence of hypoxanthine phosphoribosyl-transferase activity in the 1R cell and its presence in the progeny. Images PMID:4516198

  7. Identification of a diazinon-metabolizing glutathione S-transferase in the silkworm, Bombyx mori

    PubMed Central

    Yamamoto, Kohji; Yamada, Naotaka

    2016-01-01

    The glutathione S-transferase superfamily play key roles in the metabolism of numerous xenobiotics. We report herein the identification and characterization of a novel glutathione S-transferase in the silkworm, Bombyx mori. The enzyme (bmGSTu2) conjugates glutathione to 1-chloro-2,4-dinitrobenzene, as well as metabolizing diazinon, one of the organophosphate insecticides. Quantitative reverse transcription–polymerase chain reaction analysis of transcripts demonstrated that bmGSTu2 expression was induced 1.7-fold in a resistant strain of B. mori. Mutagenesis of putative amino acid residues in the glutathione-binding site revealed that Ile54, Glu66, Ser67, and Asn68 are crucial for enzymatic function. These results provide insights into the catalysis of glutathione conjugation in silkworm by bmGSTu2 and into the detoxification of organophosphate insecticides. PMID:27440377

  8. Design and synthesis of potent inhibitors of the mono(ADP-ribosyl)transferase, PARP14.

    PubMed

    Upton, Kristen; Meyers, Matthew; Thorsell, Ann-Gerd; Karlberg, Tobias; Holechek, Jacob; Lease, Robert; Schey, Garrett; Wolf, Emily; Lucente, Adrianna; Schüler, Herwig; Ferraris, Dana

    2017-07-01

    A series of (Z)-4-(3-carbamoylphenylamino)-4-oxobut-2-enyl amides were synthesized and tested for their ability to inhibit the mono-(ADP-ribosyl)transferase, PARP14 (a.k.a. BAL-2; ARTD-8). Two synthetic routes were established for this series and several compounds were identified as sub-micromolar inhibitors of PARP14, the most potent of which was compound 4t, IC50=160nM. Furthermore, profiling other members of this series identified compounds with >20-fold selectivity over PARP5a/TNKS1, and modest selectivity over PARP10, a closely related mono-(ADP-ribosyl)transferase. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Microinjected glutathione S-transferase Yb subunits translocate to the cell nucleus.

    PubMed Central

    Bennett, C F; Yeoman, L C

    1987-01-01

    We have previously shown that a 30 kDa DNA-binding protein isolated from rat cell nuclei exhibits the chemical and immunological properties of glutathione S-transferase Yb subunits [Bennett, Spector & Yeoman (1986) J. Cell Biol. 102, 600-609]. It was of interest, therefore, to determine whether Yb subunits isolated from rat liver nuclei would return to nuclear fractions upon reintroduction to cell cytoplasms via red-blood-cell-mediated fusion. Labelled Yb subunits were associated with nuclear fractions 60 min after cell fusion. The microinjected protein remained associated with the nuclei for 18 h and was not extractable with low-salt washes. In addition, injected Yb subunits were found to equally distribute between extractable (56%) and residual (44%) nuclear fractions. These experiments demonstrate that glutathione S-transferase Yb subunits isolated from nuclei rapidly translocate to nuclei upon reintroduction into cell cytoplasms. Images Fig. 2. PMID:3689337

  10. Involvement of cytochrome P450, glutathione S-transferase, and epoxide hydrolase in the metabolism of aflatoxin B1 and relevance to risk of human liver cancer.

    PubMed Central

    Guengerich, F P; Johnson, W W; Ueng, Y F; Yamazaki, H; Shimada, T

    1996-01-01

    In recent years there has been considerable interest in the effect of variations in activities of xenobiotic-metabolizing enzymes on cancer incidence. This interest has accelerated with the development of methods for analyzing genetic polymorphisms. However, progress in epidemiology has been slow and the contributions of polymorphisms to risks from individual chemicals and mixtures are often controversial. A series of studies is presented to show the complexities encountered with a single chemical, aflatoxin B1 (AFB1). AFB1 is oxidized by human cytochrome P450 enzymes to several products. Only one of these, the 8,9-exo-epoxide, appears to be mutagenic and the others are detoxication products. P450 3A4, which can both activate and detoxicate AFB1, is found in the liver and the small intestine. In the small intestine, the first contact after oral exposure, epoxidation would not lead to liver cancer. The (nonenzymatic) half-life of the epoxide has been determined to be approximately 1 sec at 23 degrees C and neutral pH. Although the half-life is short, AFB1-8,9-exo-epoxide does react with DNA and glutathione S-transferase. Levels of these conjugates have been measured and combined with the rate of hydrolysis in a kinetic model to predict constants for binding of the epoxide with DNA and glutathione S-transferase. A role for epoxide hydrolase in alteration of AFB1 hepatocarcinogenesis has been proposed, although experimental evidence is lacking. Some inhibition of microsome-generated genotoxicity was observed with rat epoxide hydrolase; further information on the extent of contribution of this enzyme to AFB1 metabolism is not yet available. PMID:8781383

  11. The synthesis of ethacrynic acid thiazole derivatives as glutathione S-transferase pi inhibitors.

    PubMed

    Li, Ting; Liu, Guyue; Li, Hongcai; Yang, Xinmei; Jing, Yongkui; Zhao, Guisen

    2012-04-01

    Glutathione S-transferase pi (GSTpi) is a phase II enzyme which protects cells from death and detoxifies chemotherapeutic agents in cancer cells. Ethacrynic acid (EA) is a weak GSTpi inhibitor. Structure modifications were done to improve the ability of EA to inhibit GSTpi activity. Eighteen EA thiazole derivatives were designed and synthesized. Compounds 9a, 9b and 9c with a replacement of carboxyl group of EA by a heterocyclic thiazole exhibited improvement over EA to inhibit GSTpi activity.

  12. Human glutathione S-transferases. Characterization of the anionic forms from lung and placenta.

    PubMed Central

    Dao, D D; Partridge, C A; Kurosky, A; Awasthi, Y C

    1984-01-01

    Anionic glutathione S-transferases were purified from human lung and placenta. Chemical and immunochemical characterization, including polyacrylamide-gel electrophoresis, gave strong evidence that the anionic lung and placental enzymes are chemically similar, if not identical, proteins. The electrophoretic mobilities of both proteins were identical in conventional alkaline gels as well as in gels containing sodium dodecyl sulphate. Gel filtration of the intact active enzyme established an Mr value of 45000; however, with sodium dodecyl sulphate/polyacrylamide-gel electrophoresis under dissociating conditions a subunit Mr of 22500 was obtained. Amino acid sequence analysis of the N-terminal region of the placental enzyme revealed a single polypeptide sequence identical with that of lung. Results obtained from immunoelectrophoresis, immunotitration, double immunodiffusion and rocket immunoelectrophoresis also indicated the anionic lung and placental enzymes to be closely similar. The chemical similarity of these two proteins was further supported by protein compositional analysis and fragment analysis after chemical hydrolysis. Immunochemical comparison of the anionic lung and placental enzymes with human liver glutathione S-transferases revealed cross-reactivity with the anionic omega enzyme, but no cross-reactivity was detectable with the cationic enzymes. Comparison of the N-terminal region of the human anionic enzyme with reported sequences of rat liver glutathione S-transferases gave strong evidence of chemical similarity, indicating that these enzymes are evolutionarily related. However, computer analysis of the 30-residue N-terminal sequence did not show any significant chemical similarity to any other reported protein sequence, pointing to the fact that the glutathione S-transferases represent a unique class of proteins. Images Fig. 2. Fig. 5. Fig. 6. Fig. 7. PMID:6466318

  13. Characterization of a glycosyl transferase inactivating macrolides, encoded by gimA from Streptomyces ambofaciens.

    PubMed

    Gourmelen, A; Blondelet-Rouault, M H; Pernodet, J L

    1998-10-01

    In Streptomyces ambofaciens, the producer of the macrolide antibiotic spiramycin, an open reading frame (ORF) was found downstream of srmA, a gene conferring resistance to spiramycin. The deduced product of this ORF had high degrees of similarity to Streptomyces lividans glycosyl transferase, which inactivates macrolides, and this ORF was called gimA. The cloned gimA gene was expressed in a susceptible host mutant of S. lividans devoid of any background macrolide-inactivating glycosyl transferase activity. In the presence of UDP-glucose, cell extracts from this strain could inactivate various macrolides by glycosylation. Spiramycin was not inactivated but forocidin, a spiramycin precursor, was modified. In vivo studies showed that gimA could confer low levels of resistance to some macrolides. The spectrum of this resistance differs from the one conferred by a rRNA monomethylase, such as SrmA. In S. ambofaciens, gimA was inactivated by gene replacement, without any deleterious effect on the survival of the strain, even under spiramycin-producing conditions. But the overexpression of gimA led to a marked decrease in spiramycin production. Studies with extracts from wild-type and gimA-null mutant strains revealed the existence of another macrolide-inactivating glycosyl transferase activity with a different substrate specificity. This activity might compensate for the effect of gimA inactivation.

  14. Characterization of a Glycosyl Transferase Inactivating Macrolides, Encoded by gimA from Streptomyces ambofaciens

    PubMed Central

    Gourmelen, Anne; Blondelet-Rouault, Marie-Hélène; Pernodet, Jean-Luc

    1998-01-01

    In Streptomyces ambofaciens, the producer of the macrolide antibiotic spiramycin, an open reading frame (ORF) was found downstream of srmA, a gene conferring resistance to spiramycin. The deduced product of this ORF had high degrees of similarity to Streptomyces lividans glycosyl transferase, which inactivates macrolides, and this ORF was called gimA. The cloned gimA gene was expressed in a susceptible host mutant of S. lividans devoid of any background macrolide-inactivating glycosyl transferase activity. In the presence of UDP-glucose, cell extracts from this strain could inactivate various macrolides by glycosylation. Spiramycin was not inactivated but forocidin, a spiramycin precursor, was modified. In vivo studies showed that gimA could confer low levels of resistance to some macrolides. The spectrum of this resistance differs from the one conferred by a rRNA monomethylase, such as SrmA. In S. ambofaciens, gimA was inactivated by gene replacement, without any deleterious effect on the survival of the strain, even under spiramycin-producing conditions. But the overexpression of gimA led to a marked decrease in spiramycin production. Studies with extracts from wild-type and gimA-null mutant strains revealed the existence of another macrolide-inactivating glycosyl transferase activity with a different substrate specificity. This activity might compensate for the effect of gimA inactivation. PMID:9756764

  15. Euphorbia characias latex: micromorphology of rubber particles and rubber transferase activity.

    PubMed

    Spanò, Delia; Pintus, Francesca; Esposito, Francesca; Loche, Danilo; Floris, Giovanni; Medda, Rosaria

    2015-02-01

    We have recently characterized a natural rubber in the latex of Euphorbia characias. Following that study, we here investigated the rubber particles and rubber transferase in that Mediterranean shrub. Rubber particles, observed by scanning electron microscopy, are spherical in shape with diameter ranging from 0.02 to 1.2 μm. Washed rubber particles exhibit rubber transferase activity with a rate of radiolabeled [(14)C]IPP incorporation of 4.5 pmol min(-1)mg(-1). Denaturing electrophoresis profile of washed rubber particles reveals a single protein band of 37 kDa that is recognized in western blot analysis by antibodies raised against the synthetic peptide whose sequence, DVVIRTSGETRLSNF, is included in one of the five regions conserved among cis-prenyl chain elongation enzymes. The cDNA nucleotide sequence of E. characias rubber transferase (GenBank JX564541) and the deduced amino acid sequence appear to be highly homologous to the sequence of several plant cis-prenyltransferases.

  16. Characterization of Affinity-Purified Isoforms of Acinetobacter calcoaceticus Y1 Glutathione Transferases

    PubMed Central

    Chee, Chin-Soon; Tan, Irene Kit-Ping; Alias, Zazali

    2014-01-01

    Glutathione transferases (GST) were purified from locally isolated bacteria, Acinetobacter calcoaceticus Y1, by glutathione-affinity chromatography and anion exchange, and their substrate specificities were investigated. SDS-polyacrylamide gel electrophoresis revealed that the purified GST resolved into a single band with a molecular weight (MW) of 23 kDa. 2-dimensional (2-D) gel electrophoresis showed the presence of two isoforms, GST1 (pI 4.5) and GST2 (pI 6.2) with identical MW. GST1 was reactive towards ethacrynic acid, hydrogen peroxide, 1-chloro-2,4-dinitrobenzene, and trans,trans-hepta-2,4-dienal while GST2 was active towards all substrates except hydrogen peroxide. This demonstrated that GST1 possessed peroxidase activity which was absent in GST2. This study also showed that only GST2 was able to conjugate GSH to isoproturon, a herbicide. GST1 and GST2 were suggested to be similar to F0KLY9 (putative glutathione S-transferase) and F0KKB0 (glutathione S-transferase III) of Acinetobacter calcoaceticus strain PHEA-2, respectively. PMID:24892084

  17. [Prevention of oral diseases].

    PubMed

    Vodanović, Marin

    2013-06-01

    Oral health is essential to general health and quality of life. Ever more people are affected with oral diseases. Dental caries, gingivitis and periodontitis are the most common oral diseases and they can be prevented. Oral health promotion and oral disease prevention programs should be incorporated in national health strategies. Inability to understand health information can be a profound disadvantage to patients when asked to take responsibility for their health. Increasing the level of oral health literacy and improvement of communication between patients and dentists by avoiding the usage of professional dental terminology should be included in each oral prevention program.

  18. Influence of Culture Medium on the Glucosyl Transferase- and Dextran-Binding Capacity of Streptococcus mutans 6715 Cells

    PubMed Central

    Spinell, D. M.; Gibbons, R. J.

    1974-01-01

    Growth of Streptococcus mutans 6715 in a medium containing trace amounts of sucrose or dextran promotes cell-associated glucosyl transferase activity and increases the dextran-binding capacity of the organisms. PMID:4140162

  19. Purification and characterization of hepatic glutathione S-transferases of rhesus monkeys. A family of enzymes similar to the human hepatic glutathione S-transferases.

    PubMed Central

    Hoesch, R M; Boyer, T D

    1988-01-01

    Thirteen forms of glutathione S-transferase were purified from the livers of female rhesus monkeys (Macaque mulatta). Most (74.7%) of the activity in the hepatic cytosol adhered well to the GSH affinity column and could be eluted only with the addition of GSH to the eluting buffer. The predominant isoenzymes (n = 5) in this 'high-affinity' fraction had alkaline pI values (greater than 9.0) and contained a subunit with an Mr value of 24,000. All of these isoenzymes had high organic peroxidase activity and, on the basis of amino acid analysis, substrate specificities and affinity for non-substrate ligands, appear to belong to the family of glutathione S-transferases that have been termed alpha [Mannervik, Alin, Guthenberg, Jensson, Tahir, Warholm & Jörnvall (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 7202-7206]. Also within the high-affinity fraction was an isoenzyme with an acidic (5.8) pI value. This acidic isoenzyme was composed of a unique subunit (Mr 23,000). The N-terminal sequence (ten residues) of this acidic enzyme was identical with that of a human form that is referred to as pi. The predominant form of enzyme in the 'low-affinity' (eluted from the GSH affinity column with an increase in buffer pH) fraction was a homodimer of a 26,000-Mr subunit. It had an alkaline pI (greater than 9.0) but it lacked organic peroxidase activity. The N-terminal sequence (ten residues) of this enzyme was identical with that of a human enzyme referred to as mu. The substrate specificities and affinity for non-substrate ligands of this monkey enzyme also were similar to those of the human enzyme. In conclusion, the liver cytosol of rhesus monkeys contains a number of glutathione S-transferase isoenzymes that are very similar to the human hepatic enzymes. Images Fig. 3. PMID:3390162

  20. Crystallographic trapping of the glutamyl-CoA thioester intermediate of family I CoA transferases

    SciTech Connect

    Rangarajan,E.; Li, Y.; Ajamian, E.; Iannuzzi, P.; Kernaghan, S.; Fraser, M.; Cygler, M.; Matte, A.

    2005-01-01

    Coenzyme A transferases are involved in a broad range of biochemical processes in both prokaryotes and eukaryotes, and exhibit a diverse range of substrate specificities. The YdiF protein from Escherichia coli O157:H7 is an acyl-CoA transferase of unknown physiological function, and belongs to a large sequence family of CoA transferases, present in bacteria to humans, which utilize oxoacids as acceptors. In vitro measurements showed that YdiF displays enzymatic activity with short-chain acyl-CoAs. The crystal structures of YdiF and its complex with CoA, the first co-crystal structure for any Family I CoA transferase, have been determined and refined at 1.9 and 2.0 Angstrom resolution, respectively. YdiF is organized into tetramers, with each monomer having an open {alpha}/{beta} structure characteristic of Family I CoA transferases. Co-crystallization of YdiF with a variety of CoA thioesters in the absence of acceptor carboxylic acid resulted in trapping a covalent {gamma}-glutamyl-CoA thioester intermediate. The CoA binds within a well defined pocket at the N- and C-terminal domain interface, but makes contact only with the C-terminal domain. The structure of the YdiF complex provides a basis for understanding the different catalytic steps in the reaction of Family I CoA transferases.

  1. Expression of human glutathione S-transferase 2 in Escherichia coli. Immunological comparison with the basic glutathione S-transferases isoenzymes from human liver.

    PubMed Central

    Board, P G; Pierce, K

    1987-01-01

    A plasmid, termed pTacGST2, which contains the complete coding sequence of a GST2 (glutathione S-transferase 2) subunit and permits the expression of the protein in Escherichia coli was constructed. The expressed protein had the same subunit Mr as the enzyme from normal human liver and retained its catalytic function with both GST and glutathione peroxidase activity. Antiserum raised against the bacterially synthesized protein cross-reacted with all the basic GST isoenzymes in human liver. The electrophoretic mobility in agarose of the bacterially expressed isoenzyme suggested that its pI is identical with that of the cationic isoenzyme from human liver previously termed GST2 type 1. The available evidence suggests that the three common cationic isoenzymes found in human liver are the products of two very similar gene loci. Images Fig. 3. Fig. 4. Fig. 5. PMID:3325043

  2. Extreme Substrate Promiscuity of the Neisseria Oligosaccharyl Transferase Involved in Protein O-Glycosylation*S⃞

    PubMed Central

    Faridmoayer, Amirreza; Fentabil, Messele A.; Haurat, M. Florencia; Yi, Wen; Woodward, Robert; Wang, Peng George; Feldman, Mario F.

    2008-01-01

    Neisseria meningitidis PglL belongs to a novel family of bacterial oligosaccharyltransferases (OTases) responsible for O-glycosylation of type IV pilins. Although members of this family are widespread among pathogenic bacteria, there is little known about their mechanism. Understanding the O-glycosylation process may uncover potential targets for therapeutic intervention, and can open new avenues for the exploitation of these pathways for biotechnological purposes. In this work, we demonstrate that PglL is able to transfer virtually any glycan from the undecaprenyl pyrophosphate (UndPP) carrier to pilin in engineered Escherichia coli and Salmonella cells. Surprisingly, PglL was also able to interfere with the peptidoglycan biosynthetic machinery and transfer peptidoglycan subunits to pilin. This represents a previously unknown post-translational modification in bacteria. Given the wide range of glycans transferred by PglL, we reasoned that substrate specificity of PglL lies in the lipid carrier. To test this hypothesis we developed an in vitro glycosylation system that employed purified PglL, pilin, and the lipid farnesyl pyrophosphate (FarPP) carrying a pentasaccharide that had been synthesized by successive chemical and enzymatic steps. Although FarPP has different stereochemistry and a significantly shorter aliphatic chain than the natural lipid substrate, the pentasaccharide was still transferred to pilin in our system. We propose that the primary roles of the lipid carrier during O-glycosylation are the translocation of the glycan into the periplasm, and the positioning of the pyrophosphate linker and glycan adjacent to PglL. The unique characteristics of PglL make this enzyme a promising tool for glycoengineering novel glycan-based vaccines and therapeutics. PMID:18930921

  3. Biosynthesis of 2-hydroxyacid-containing polyhydroxyalkanoates by employing butyryl-CoA transferases in metabolically engineered Escherichia coli.

    PubMed

    David, Yokimiko; Joo, Jeong Chan; Yang, Jung Eun; Oh, Young Hoon; Lee, Sang Yup; Park, Si Jae

    2017-09-01

    We previously reported the production of polyhydroxyalkanoates (PHAs) containing 2-hydroxyacid monomers by expressing evolved Pseudomonas sp. 6-19 PHA synthase and Clostridium propionicum propionyl-CoA transferase in engineered microorganisms. Here, we examined four butyryl-CoA transferases from Roseburia sp., Eubacterium hallii, Faecalibacterium prausnitzii, and Anaerostipes caccae as potential CoA-transferases to support synthesis of polymers having 2HA monomer. In vitro activity analyses of the four butyryl-CoA transferases suggested that each butyryl-CoA transferase has different activities towards 2-hydroxybutyrate (2HB), 3-hydroxybutyrate (3HB), and lactate (LA). When Escherichia coli XL1-Blue expressing Pseudomonas sp. 6-19 PhaC1437 along with one butyryl-CoA transferase was cultured in chemically defined MR medium containing 20 g/L of glucose, 2 g/L of sodium 3-hydroxybutyrate, and various concentrations of sodium 2-hydroxybutyrate, PHAs consisting of 3HB, 2HB, and LA were produced. The monomer composition of PHAs agreed well with the substrate specificities of butyryl-CoA transferases from E. hallii, F. prausnitzii, and A. caccae, but not Roseburia sp. When E. coli XL1-Blue expressing PhaC1437 and E. hallii butyryl-CoA transferase was cultured in MR medium containing 20 g/L of glucose and 2 g/L of sodium 2-hydroxybutyrate, P(65.7 mol% 2HB-co-34.3 mol% LA) was produced with the highest PHA content of 30 wt%. Butyryl-CoA transferases also supported the production of P(3HB-co-2HB-co-LA) from glucose as the sole carbon source in E. coli XL1-Blue strains when one of these bct genes was expressed with phaC1437, cimA3.7, leuBCD, panE, and phaAB genes. Butyryl-CoA transferases characterized in this study can be used for engineering of microorganisms that produce PHAs containing novel 2-hydroxyacid monomers. This article is protected by copyright. All rights reserved.

  4. Three CoA Transferases Involved in the Production of Short Chain Fatty Acids in Porphyromonas gingivalis

    PubMed Central

    Sato, Mitsunari; Yoshida, Yasuo; Nagano, Keiji; Hasegawa, Yoshiaki; Takebe, Jun; Yoshimura, Fuminobu

    2016-01-01

    Butyryl-CoA:acetate CoA transferase, which produces butyrate and acetyl-CoA from butyryl-CoA and acetate, is responsible for the final step of butyrate production in bacteria. This study demonstrates that in the periodontopathogenic bacterium Porphyromonas gingivalis this reaction is not catalyzed by PGN_1171, previously annotated as butyryl-CoA:acetate CoA transferase, but by three distinct CoA transferases, PGN_0725, PGN_1341, and PGN_1888. Gas chromatography/mass spectrometry (GC-MS) and spectrophotometric analyses were performed using crude enzyme extracts from deletion mutant strains and purified recombinant proteins. The experiments revealed that, in the presence of acetate, PGN_0725 preferentially utilized butyryl-CoA rather than propionyl-CoA. By contrast, this preference was reversed in PGN_1888. The only butyryl-CoA:acetate CoA transferase activity was observed in PGN_1341. Double reciprocal plots revealed that all the reactions catalyzed by these enzymes follow a ternary-complex mechanism, in contrast to previously characterized CoA transferases. GC-MS analysis to determine the concentrations of short chain fatty acids (SCFAs) in culture supernatants of P. gingivalis wild type and mutant strains revealed that PGN_0725 and PGN_1888 play a major role in the production of butyrate and propionate, respectively. Interestingly, a triple deletion mutant lacking PGN_0725, PGN_1341, and PGN_1888 produced low levels of SCFAs, suggesting that the microorganism contains CoA transferase(s) in addition to these three enzymes. Growth rates of the mutant strains were mostly slower than that of the wild type, indicating that many carbon compounds produced in the SCFA synthesis appear to be important for the biological activity of this microorganism. PMID:27486457

  5. Salivary glyco-sialylation changes monitors oral carcinogenesis.

    PubMed

    Vajaria, Bhairavi N; Patel, Kinjal R; Begum, Rasheedunnisa; Patel, Jayendra B; Shah, Franky D; Joshi, Geeta M; Patel, Prabhudas S

    2014-12-01

    Alterations in cell membrane glycosylation play important role in oral carcinogenesis. The present study evaluated salivary sialylation changes i.e. total sialic acid (TSA), sialidase activity, linkage specific (α2-3 and α2-6) sialoproteins and sialyl transferase (ST) activity in controls, patients with oral precancerous conditions (OPC) and oral cancer. Subjects enrolled included 100 controls, 50 patients with OPC, 100 oral cancer patients, and 30 post treatment follow-ups. TSA was estimated by spectrophotometric method, sialidase activity by spectrofluorometric assay and linkage specific biotinylated lectins (α2-3: sambucus nigra agglutinin and α2-6: maackia amurensis agglutinin) were used to detect α-2,3 and α-2,6 STs and sialoproteins by ELISA and dot blot respectively. An increasing trend of salivary TSA/TP ratio, sialidase activity, α2-3 sialoproteins, α-2,3 and α-2,6 ST activities was observed from controls to patients with OPC to oral cancer patients and levels were significantly elevated in oral cancer patients as compared to the controls. Sialidase activity exhibited significant association with metastasis and infiltration. Sialidase activity, TSA/TP ratio, α-2,3 and α-2,6 ST activities were found to be higher in patients with metastasis as compared to patients without metastasis. A progressive increase in TSA/TP ratio, sialidase activity, α2-3 and α2-6 sialoproteins was observed from controls to early to advanced stage of the disease. Sialidase activity, α2-3 and α2-6 sialoproteins and ST activities were found to be decreased in complete responders; while levels were elevated in non-responders. The results documented utility of salivary sialylation endpoints, a non invasive tool in monitoring of oral carcinogenesis.

  6. Characterization of glutathione transferases involved in the pathogenicity of Alternaria brassicicola.

    PubMed

    Calmes, Benoit; Morel-Rouhier, Mélanie; Bataillé-Simoneau, Nelly; Gelhaye, Eric; Guillemette, Thomas; Simoneau, Philippe

    2015-06-18

    Glutathione transferases (GSTs) represent an extended family of multifunctional proteins involved in detoxification processes and tolerance to oxidative stress. We thus anticipated that some GSTs could play an essential role in the protection of fungal necrotrophs against plant-derived toxic metabolites and reactive oxygen species that accumulate at the host-pathogen interface during infection. Mining the genome of the necrotrophic Brassica pathogen Alternaria brassicicola for glutathione transferase revealed 23 sequences, 17 of which could be clustered into the main classes previously defined for fungal GSTs and six were 'orphans'. Five isothiocyanate-inducible GSTs from five different classes were more thoroughly investigated. Analysis of their catalytic properties revealed that two GSTs, belonging to the GSTFuA and GTT1 classes, exhibited GSH transferase activity with isothiocyanates (ITC) and peroxidase activity with cumene hydroperoxide, respectively. Mutant deficient for these two GSTs were however neither more susceptible to ITC nor less aggressive than the wild-type parental strain. By contrast mutants deficient for two other GSTs, belonging to the Ure2pB and GSTO classes, were distinguished by their hyper-susceptibility to ITC and low aggressiveness against Brassica oleracea. In particular AbGSTO1 could participate in cell tolerance to ITC due to its glutathione-dependent thioltransferase activity. The fifth ITC-inducible GST belonged to the MAPEG class and although it was not possible to produce the soluble active form of this protein in a bacterial expression system, the corresponding deficient mutant failed to develop normal symptoms on host plant tissues. Among the five ITC-inducible GSTs analyzed in this study, three were found essential for full aggressiveness of A. brassicicola on host plant. This, to our knowledge is the first evidence that GSTs might be essential virulence factors for fungal necrotrophs.

  7. Glutathione Transferase from Trichoderma virens Enhances Cadmium Tolerance without Enhancing Its Accumulation in Transgenic Nicotiana tabacum

    PubMed Central

    Dixit, Prachy; Mukherjee, Prasun K.; Ramachandran, V.; Eapen, Susan

    2011-01-01

    Background Cadmium (Cd) is a major heavy metal pollutant which is highly toxic to plants and animals. Vast agricultural areas worldwide are contaminated with Cd. Plants take up Cd and through the food chain it reaches humans and causes toxicity. It is ideal to develop plants tolerant to Cd, without enhanced accumulation in the edible parts for human consumption. Glutathione transferases (GST) are a family of multifunctional enzymes known to have important roles in combating oxidative stresses induced by various heavy metals including Cd. Some GSTs are also known to function as glutathione peroxidases. Overexpression/heterologous expression of GSTs is expected to result in plants tolerant to heavy metals such as Cd. Results Here, we report cloning of a glutathione transferase gene from Trichoderma virens, a biocontrol fungus and introducing it into Nicotiana tabacum plants by Agrobacterium-mediated gene transfer. Transgenic nature of the plants was confirmed by Southern blot hybridization and expression by reverse transcription PCR. Transgene (TvGST) showed single gene Mendelian inheritance. When transgenic plants expressing TvGST gene were exposed to different concentrations of Cd, they were found to be more tolerant compared to wild type plants, with transgenic plants showing lower levels of lipid peroxidation. Levels of different antioxidant enzymes such as glutathione transferase, superoxide dismutase, ascorbate peroxidase, guiacol peroxidase and catalase showed enhanced levels in transgenic plants expressing TvGST compared to control plants, when exposed to Cd. Cadmium accumulation in the plant biomass in transgenic plants were similar or lower than wild-type plants. Conclusion The results of the present study suggest that transgenic tobacco plants expressing a Trichoderma virens GST are more tolerant to Cd, without enhancing its accumulation in the plant biomass. It should be possible to extend the present results to crop plants for developing Cd tolerance and

  8. MIF protein are theta-class glutathione S-transferase homologs.

    PubMed

    Blocki, F A; Ellis, L B; Wackett, L P

    1993-12-01

    MIF proteins are mammalian polypeptides of approximately 13,000 molecular weight. This class includes human macrophage migration inhibitory factor (MIF), a rat liver protein that has glutathione S-transferase (GST) activity (TRANSMIF), and the mouse delayed early response gene 6 (DER6) protein. MIF proteins were previously linked to GSTs by demonstrating transferase activity and observing N-terminal sequence homology with a mu-class GST (Blocki, F.A., Schlievert, P.M., & Wackett, L.P., 1992, Nature 360, 269-270). In this study, MIF proteins are shown to be structurally related to the theta class of GSTs. This is established in three ways. First, unique primary sequence patterns are developed for each of the GST gene classes. The patterns identify the three MIF proteins as theta-like transferase homologs. Second, pattern analysis indicates that GST members of the theta class contain a serine residue in place of the N-terminal tyrosine that is implicated in glutathione deprotonation and activation in GSTs of known structure (Liu, S., et al., 1992, J. Biol. Chem. 267, 4296-4299). The MIF proteins contain a threonine at this position. Third, polyclonal antibodies raised against recombinant human MIF cross-react on Western blots with rat theta GST but not with alpha and mu GSTs. That MIF proteins have glutathione-binding ability may provide a common structural key toward understanding the varied functions of this widely distributed emerging gene family. Because theta is thought to be the most ancient evolutionary GST class, MIF proteins may have diverged early in evolution but retained a glutathione-binding domain.

  9. Disparities in Oral Health

    MedlinePlus

    ... Tips Disparities in Oral Health Oral Health Conditions Periodontal Disease Community Water Fluoridation Water Fluoridation Basics Over 70 ... 2% of U.S. adults have some form of periodontal disease. In adults aged 65 and older, 70.1% ...

  10. Nicotine Oral Inhalation

    MedlinePlus

    Nicotine oral inhalation is used to help people stop smoking. Nicotine oral inhalation should be used together with a ... support groups, counseling, or specific behavioral change techniques. Nicotine inhalation is in a class of medications called ...

  11. Peptides in oral diseases.

    PubMed

    Lucchese, Alberta; Guida, Agostino; Petruzzi, Massimo; Capone, Giovanni; Laino, Luigi; Serpico, Rosario

    2012-01-01

    The oral cavity is home to numerous viruses and micro-organisms recognized as having a role in various oral diseases as well as in infections in other parts of the body. Indeed, in general a microbial infection underlies or is believed to underlie the ample spectrum of oral diseases, from tooth enamel decay to periodontal lesions, from candidiasis to virus-induced oral squamous cell carcinomas, and bullous autoimmune oral disorders. This clinico-pathological context stresses the need of targeted therapies to specifically kill infectious agents in a complex environment such as the oral cavity, and explains the current interest in exploring peptide-based therapeutic approaches in oral and dental research. Here, we review the therapeutic potential of antimicrobial peptides such as LL-37, beta defensins, adrenomedullin, histatins, and of various peptides modulating gene expression and immuno-biological interaction(s) in oral diseases.

  12. Albuterol Oral Inhalation

    MedlinePlus

    ... and airways). Albuterol inhalation aerosol and powder for oral inhalation is also used to prevent breathing difficulties ... years of age and older. Albuterol powder for oral inhalation (Proair Respiclick) is used in children 12 ...

  13. Glutathione-S-transferase (GST)-fusion based assays for studying protein-protein interactions.

    PubMed

    Vikis, Haris G; Guan, Kun-Liang

    2015-01-01

    Glutathione-S-transferase (GST)-fusion proteins have become an effective reagent to use in the study of protein-protein interactions. GST-fusion proteins can be produced in bacterial and mammalian cells in large quantities and purified rapidly. GST can be coupled to a glutathione matrix, which permits its use as an effective affinity column to study interactions in vitro or to purify protein complexes in cells expressing the GST-fusion protein. Here, we provide a technical description of the utilization of GST-fusion proteins as both a tool to study protein-protein interactions and also as a means to purify interacting proteins.

  14. Glutathione-Binding Site of a Bombyx mori Theta-Class Glutathione Transferase

    PubMed Central

    Hossain, M. D. Tofazzal; Yamada, Naotaka; Yamamoto, Kohji

    2014-01-01

    The glutathione transferase (GST) superfamily plays key roles in the detoxification of various xenobiotics. Here, we report the isolation and characterization of a silkworm protein belonging to a previously reported theta-class GST family. The enzyme (bmGSTT) catalyzes the reaction of glutathione with 1-chloro-2,4-dinitrobenzene, 1,2-epoxy-3-(4-nitrophenoxy)-propane, and 4-nitrophenethyl bromide. Mutagenesis of highly conserved residues in the catalytic site revealed that Glu66 and Ser67 are important for enzymatic function. These results provide insights into the catalysis of glutathione conjugation in silkworm by bmGSTT and into the metabolism of exogenous chemical agents. PMID:24848539

  15. Genetic Variations in Human Glutathione Transferase Enzymes: Significance for Pharmacology and Toxicology

    PubMed Central

    Josephy, P. David

    2010-01-01

    Glutathione transferase enzymes (GSTs) catalyze reactions in which electrophiles are conjugated to the tripeptide thiol glutathione. While many GST-catalyzed transformations result in the detoxication of xenobiotics, a few substrates, such as dihaloalkanes, undergo bioactivation to reactive intermediates. Many molecular epidemiological studies have tested associations between polymorphisms (especially, deletions) of human GST genes and disease susceptibility or response to therapy. This review presents a discussion of the biochemistry of GSTs, the sources—both genetic and environmental—of interindividual variation in GST activities, and their implications for pharmaco- and toxicogenetics; particular attention is paid to the Theta class GSTs. PMID:20981235

  16. New C25 carbamate rifamycin derivatives are resistant to inactivation by ADP-ribosyl transferases.

    PubMed

    Combrink, Keith D; Denton, Daniel A; Harran, Susan; Ma, Zhenkun; Chapo, Katrina; Yan, Dalai; Bonventre, Eric; Roche, Eric D; Doyle, Timothy B; Robertson, Gregory T; Lynch, Anthony S

    2007-01-15

    A novel series of 3-morpholino rifamycins in which the C25 acetate group was replaced by a carbamate group were prepared and found to exhibit significantly improved antimicrobial activity than rifampin against Mycobacterium smegmatis. Further characterization of such compounds suggests that relatively large groups attached to the rifamycin core via a C25 carbamate linkage prevent inactivation via ribosylation of the C23 alcohol as catalyzed by the endogenous rifampin ADP-ribosyl transferase of M. smegmatis. SAR studies of the C25 carbamate rifamycin series against M. smegmatis and other bacteria are reported.

  17. Fucosylation of xyloglucan: localization of the transferase in dictyosomes of pea stem cells. [Pisum sativum

    SciTech Connect

    Camirand, A.; Brummell, D.; MacLachlan, G.

    1987-07-01

    Microsomal membranes from elongating regions of etiolated Pisum sativum stems were separated by rate-zonal centrifugation on Renografin gradients. The transfer of labeled fucose and xylose from GDP-(/sup 14/C) fucose and UDP-(/sup 14/C)xylose to xyloglucan occurred mainly in dictyosome-enriched fractions. No transferase activity was detected in secretory vesicle fractions. Pulse-chase experiments using pea stem slices incubated with (/sup 3/H)fucose suggest that xyloglucan chains are fucosylated and their structure completed within the dictyosomes, before being transported to the cell wall by secretory vesicles.

  18. Glutathion S-transferase activity and DDT-susceptibility of Malaysian mosquitos.

    PubMed

    Lee, H L; Chong, W L

    1995-03-01

    Comparative DDT-susceptibility status and glutathion s-transferase (GST) activity of Malaysian Anopheles maculatus, Culex quinquefasciatus and Aedes aegypti was investigated to ascertain the role of this enzyme in DDT resistance. The standardised WHO dose-mortality bioassay tests were used to determine DDT susceptibility in these mosquitos, whilst GST microassay (Brogdon and Barber, 1990) was conducted to measure the activity of this enzyme in mosquito homogenate. It appeared that DDT susceptibility status of Malaysian mosquitos was not correlated with GST activity.

  19. Genomic organization of the glutathione S-transferase family in insects.

    PubMed

    Friedman, Robert

    2011-12-01

    Cytosolic glutathione S-transferases (GSTs) are a large and diverse gene family in insects. They are classified into six major subclasses. Sigma, Omega, Zeta, and Theta have representatives across Metazoa while Delta and Epsilon are specific to Insecta and Holometabola, respectively. In this study, GSTs are assigned to a subclass by a combination of literature, phylogenetic, and genomic evidence. Moreover, it is confirmed that GSTs frequently cluster by genomic position as a result of recent gene expansions. These expansions are largely explained by the number of protein-coding genes in the genome, although life history is another contributing factor. Copyright © 2011 Elsevier Inc. All rights reserved.

  20. The Phosphopantetheinyl Transferases: Catalysis of a Posttranslational Modification Crucial for Life

    PubMed Central

    Beld, Joris; Sonnenschein, Eva C.; Vickery, Christopher R.; Noel, Joseph P.; Burkart, Michael D.

    2014-01-01

    Although holo-acyl carrier protein synthase, AcpS, a phosphopantetheinyl transferase (PPTase), was characterized in the 1960s, it was not until the publication of the landmark paper by Lambalot et al. in 1996 that PPTases garnered wide-spread attention being classified as a distinct enzyme superfamily. In the past two decades an increasing number of papers has been published on PPTases ranging from identification, characterization, structure determination, mutagenesis, inhibition, and engineering in synthetic biology. In this review, we comprehensively discuss all current knowledge on this class of enzymes that post-translationally install a 4′-phosphopantetheine arm on various carrier proteins. PMID:24292120

  1. HAD Oral History Project

    NASA Astrophysics Data System (ADS)

    Holbrook, Jarita

    2014-01-01

    The Historical Astronomy Division is the recipient of an American Institute of Physics Neils Bohr Library Grant for Oral History. HAD has assembled a team of volunteers to conduct oral history interviews since May 2013. Each oral history interview varies in length between two and six hours. This presentation is an introduction to the HAD Oral History Project and the activities of the team during the first six months of the grant.

  2. Oral Steroids for Dermatitis.

    PubMed

    Fisher, Andrew D; Clarke, Jesse; Williams, Timothy K

    2015-01-01

    Contact/allergic dermatitis is frequently treated inappropriately with lower-than-recommended doses or inadequate duration of treatment with oral and intramuscular glucocorticoids. This article highlights a case of dermatitis in a Ranger Assessment and Selection Program student who was improperly treated over 2 weeks with oral steroids after being bit by Cimex lectularius, commonly known as bed bugs. The article also highlights the pitfalls of improper oral steroid dosing and provides reasoning for longer-duration oral steroid treatment.

  3. Understanding Oral Learners

    ERIC Educational Resources Information Center

    Moon, W. Jay

    2012-01-01

    A five-year research project of seminary students from various cultural backgrounds revealed that the slight majority of contemporary seminary students studied are oral learners. Oral learners learn best and have their lives most transformed when professors utilize oral teaching and assessment methods. After explaining several preferences of oral…

  4. Understanding Oral Learners

    ERIC Educational Resources Information Center

    Moon, W. Jay

    2012-01-01

    A five-year research project of seminary students from various cultural backgrounds revealed that the slight majority of contemporary seminary students studied are oral learners. Oral learners learn best and have their lives most transformed when professors utilize oral teaching and assessment methods. After explaining several preferences of oral…

  5. Oral Communication K-9.

    ERIC Educational Resources Information Center

    Cottrell, June, Ed.

    This speech communication curriculum guide is designed to provide a comprehensive oral language curriculum, to suggest ways for integrating oral activities into other curriculum areas, and to stimulate ideas for using oral language in a holistic rather than a fragmentary learning environment. Following an introductory chapter on "creating the…

  6. Reversal of hypermethylation and reactivation of glutathione S-transferase pi 1 gene by curcumin in breast cancer cell line.

    PubMed

    Kumar, Umesh; Sharma, Ujjawal; Rathi, Garima

    2017-02-01

    One of the mechanisms for epigenetic silencing of tumor suppressor genes is hypermethylation of cytosine residue at CpG islands at their promoter region that contributes to malignant progression of tumor. Therefore, activation of tumor suppressor genes that have been silenced by promoter methylation is considered to be very attractive molecular target for cancer therapy. Epigenetic silencing of glutathione S-transferase pi 1, a tumor suppressor gene, is involved in various types of cancers including breast cancer. Epigenetic silencing of tumor suppressor genes can be reversed by several molecules including natural compounds such as polyphenols that can act as a hypomethylating agent. Curcumin has been found to specifically target various tumor suppressor genes and alter their expression. To check the effect of curcumin on the methylation pattern of glutathione S-transferase pi 1 gene in MCF-7 breast cancer cell line in dose-dependent manner. To check the reversal of methylation pattern of hypermethylated glutathione S-transferase pi 1, MCF-7 breast cancer cell line was treated with different concentrations of curcumin for different time periods. DNA and proteins of treated and untreated cell lines were isolated, and methylation status of the promoter region of glutathione S-transferase pi 1 was analyzed using methylation-specific polymerase chain reaction assay, and expression of this gene was analyzed by immunoblotting using specific antibodies against glutathione S-transferase pi 1. A very low and a nontoxic concentration (10 µM) of curcumin treatment was able to reverse the hypermethylation and led to reactivation of glutathione S-transferase pi 1 protein expression in MCF-7 cells after 72 h of treatment, although the IC50 value of curcumin was found to be at 20 µM. However, curcumin less than 3 µM of curcumin could not alter the promoter methylation pattern of glutathione S-transferase pi 1. Treatment of breast cancer MCF-7 cells with curcumin causes

  7. Essentials of oral cancer

    PubMed Central

    Rivera, César

    2015-01-01

    Oral cancer is one of the 10 most common cancers in the world, with a delayed clinical detection, poor prognosis, without specific biomarkers for the disease and expensive therapeutic alternatives. This review aims to present the fundamental aspects of this cancer, focused on squamous cell carcinoma of the oral cavity (OSCC), moving from its definition and epidemiological aspects, addressing the oral carcinogenesis, oral potentially malignant disorders, epithelial precursor lesions and experimental methods for its study, therapies and future challenges. Oral cancer is a preventable disease, risk factors and natural history is already being known, where biomedical sciences and dentistry in particular are likely to improve their poor clinical indicators. PMID:26617944

  8. Oral steroid contraception.

    PubMed

    Sech, Laura A; Mishell, Daniel R

    2015-11-01

    Oral steroid contraception is a popular method of family planning worldwide. Over the past several decades, this method of contraception has changed significantly by decreasing the estrogen dose, changing the progestin component, and reducing the hormone free interval. Despite the popularity of oral steroid contraception, there has been much criticism regarding the associated risks of venous thromboembolism and stroke. Despite these established, yet uncommon risks, oral steroid contraception has many important health benefits. This review highlights the available formulations of oral contraceptives along with their evidence-based associated risks and benefits. Highlights regarding future directions for development of novel oral contraceptives are also addressed.

  9. Essentials of oral cancer.

    PubMed

    Rivera, César

    2015-01-01

    Oral cancer is one of the 10 most common cancers in the world, with a delayed clinical detection, poor prognosis, without specific biomarkers for the disease and expensive therapeutic alternatives. This review aims to present the fundamental aspects of this cancer, focused on squamous cell carcinoma of the oral cavity (OSCC), moving from its definition and epidemiological aspects, addressing the oral carcinogenesis, oral potentially malignant disorders, epithelial precursor lesions and experimental methods for its study, therapies and future challenges. Oral cancer is a preventable disease, risk factors and natural history is already being known, where biomedical sciences and dentistry in particular are likely to improve their poor clinical indicators.

  10. Glutathione Transferases Superfamily: Cold-Inducible Expression of Distinct GST Genes in Brassica oleracea.

    PubMed

    Vijayakumar, Harshavardhanan; Thamilarasan, Senthil Kumar; Shanmugam, Ashokraj; Natarajan, Sathishkumar; Jung, Hee-Jeong; Park, Jong-In; Kim, HyeRan; Chung, Mi-Young; Nou, Ill-Sup

    2016-07-27

    Plants, as sessile organisms, can suffer serious growth and developmental consequences under cold stress conditions. Glutathione transferases (GSTs, EC 2.5.1.18) are ubiquitous and multifunctional conjugating proteins, which play a major role in stress responses by preventing oxidative damage by reactive oxygen species (ROS). Currently, understanding of their function(s) during different biochemical and signaling pathways under cold stress condition remain unclear. In this study, using combined computational strategy, we identified 65 Brassica oleracea glutathione transferases (BoGST) and characterized them based on evolutionary analysis into 11 classes. Inter-species and intra-species duplication was evident between BoGSTs and Arabidopsis GSTs. Based on localization analyses, we propose possible pathways in which GST genes are involved during cold stress. Further, expression analysis of the predicted putative functions for GST genes were investigated in two cold contrasting genotypes (cold tolerance and susceptible) under cold condition, most of these genes were highly expressed at 6 h and 1 h in the cold tolerant (CT) and cold susceptible (CS) lines, respectively. Overall, BoGSTU19, BoGSTU24, BoGSTF10 are candidate genes highly expressed in B. oleracea. Further investigation of GST superfamily in B. oleracea will aid in understanding complex mechanism underlying cold tolerance in plants.

  11. Glutathione Transferases Superfamily: Cold-Inducible Expression of Distinct GST Genes in Brassica oleracea

    PubMed Central

    Vijayakumar, Harshavardhanan; Thamilarasan, Senthil Kumar; Shanmugam, Ashokraj; Natarajan, Sathishkumar; Jung, Hee-Jeong; Park, Jong-In; Kim, HyeRan; Chung, Mi-Young; Nou, Ill-Sup

    2016-01-01

    Plants, as sessile organisms, can suffer serious growth and developmental consequences under cold stress conditions. Glutathione transferases (GSTs, EC 2.5.1.18) are ubiquitous and multifunctional conjugating proteins, which play a major role in stress responses by preventing oxidative damage by reactive oxygen species (ROS). Currently, understanding of their function(s) during different biochemical and signaling pathways under cold stress condition remain unclear. In this study, using combined computational strategy, we identified 65 Brassica oleracea glutathione transferases (BoGST) and characterized them based on evolutionary analysis into 11 classes. Inter-species and intra-species duplication was evident between BoGSTs and Arabidopsis GSTs. Based on localization analyses, we propose possible pathways in which GST genes are involved during cold stress. Further, expression analysis of the predicted putative functions for GST genes were investigated in two cold contrasting genotypes (cold tolerance and susceptible) under cold condition, most of these genes were highly expressed at 6 h and 1 h in the cold tolerant (CT) and cold susceptible (CS) lines, respectively. Overall, BoGSTU19, BoGSTU24, BoGSTF10 are candidate genes highly expressed in B. oleracea. Further investigation of GST superfamily in B. oleracea will aid in understanding complex mechanism underlying cold tolerance in plants. PMID:27472324

  12. Structural plasticity of Cid1 provides a basis for its distributive RNA terminal uridylyl transferase activity

    PubMed Central

    Yates, Luke A.; Durrant, Benjamin P.; Fleurdépine, Sophie; Harlos, Karl; Norbury, Chris J.; Gilbert, Robert J.C.

    2015-01-01

    Terminal uridylyl transferases (TUTs) are responsible for the post-transcriptional addition of uridyl residues to RNA 3′ ends, leading in some cases to altered stability. The Schizosaccharomyces pombe TUT Cid1 is a model enzyme that has been characterized structurally at moderate resolution and provides insights into the larger and more complex mammalian TUTs, ZCCHC6 and ZCCHC11. Here, we report a higher resolution (1.74 Å) crystal structure of Cid1 that provides detailed evidence for uracil selection via the dynamic flipping of a single histidine residue. We also describe a novel closed conformation of the enzyme that may represent an intermediate stage in a proposed product ejection mechanism. The structural insights gained, combined with normal mode analysis and biochemical studies, demonstrate that the plasticity of Cid1, particularly about a hinge region (N164–N165), is essential for catalytic activity, and provide an explanation for its distributive uridylyl transferase activity. We propose a model clarifying observed differences between the in vitro apparently processive activity and in vivo distributive monouridylylation activity of Cid1. We suggest that modulating the flexibility of such enzymes—for example by the binding of protein co-factors—may allow them alternatively to add single or multiple uridyl residues to the 3′ termini of RNA molecules. PMID:25712096

  13. Crystal Structure of Escherichia coli originated MCR-1, a phosphoethanolamine transferase for Colistin Resistance

    PubMed Central

    Hu, Menglong; Guo, Jiubiao; Cheng, Qipeng; Yang, Zhiqiang; Chan, Edward Wai Chi; Chen, Sheng; Hao, Quan

    2016-01-01

    MCR-1 is a phosphoethanolamine (pEtN) transferase that modifies the pEtN moiety of lipid A, conferring resistance to colistin, which is an antibiotic belonging to the class of polypeptide antibiotics known as polymyxins and is the last-line antibiotic used to treat multidrug resistant bacterial infections. Here we determined the crystal structure of the catalytic domain of MCR-1 (MCR-1-ED), which is originated in Escherichia coli (E. coli). MCR-1-ED was found to comprise several classical β-α-β-α motifs that constitute a “sandwich” conformation. Two interlaced molecules with different phosphorylation status of the residue T285 could give rise to two functional statuses of MCR-1 depending on the physiological conditions. MCR-1, like other known pEtN transferases, possesses an enzymatic site equipped with zinc binding residues. Interestingly, two zinc ions were found to mediate intermolecular interactions between MCR-1-ED molecules in one asymmetric unit and hence concatenation of MCR-1, allowing the protein to be oligomer. Findings of this work shall provide important insight into development of effective and clinically useful inhibitors of MCR-1 or structurally similar enzymes. PMID:27958270

  14. Structure of Human O-GlcNAc Transferase and its Complex with a Peptide Substrate

    SciTech Connect

    M Lazarus; Y Nam; J Jiang; P Sliz; S Walker

    2011-12-31

    The essential mammalian enzyme O-linked {beta}-N-acetylglucosamine transferase (O-GlcNAc transferase, here OGT) couples metabolic status to the regulation of a wide variety of cellular signalling pathways by acting as a nutrient sensor. OGT catalyses the transfer of N-acetylglucosamine from UDP-N-acetylglucosamine (UDP-GlcNAc) to serines and threonines of cytoplasmic, nuclear and mitochondrial proteins, including numerous transcription factors, tumour suppressors, kinases, phosphatases and histone-modifying proteins. Aberrant glycosylation by OGT has been linked to insulin resistance, diabetic complications, cancer and neurodegenerative diseases including Alzheimer's. Despite the importance of OGT, the details of how it recognizes and glycosylates its protein substrates are largely unknown. We report here two crystal structures of human OGT, as a binary complex with UDP (2.8 {angstrom} resolution) and as a ternary complex with UDP and a peptide substrate (1.95 {angstrom}). The structures provide clues to the enzyme mechanism, show how OGT recognizes target peptide sequences, and reveal the fold of the unique domain between the two halves of the catalytic region. This information will accelerate the rational design of biological experiments to investigate OGT's functions; it will also help the design of inhibitors for use as cellular probes and help to assess its potential as a therapeutic target.

  15. Riboswitch control of induction of aminoglycoside resistance acetyl and adenyl-transferases.

    PubMed

    He, Weizhi; Zhang, Xuhui; Zhang, Jun; Jia, Xu; Zhang, Jing; Sun, Wenxia; Jiang, Hengyi; Chen, Dongrong; Murchie, Alastair I H

    2013-08-01

    The acquisition of antibiotic resistance by human pathogens poses a significant threat to public health. The mechanisms that control the proliferation and expression of antibiotic resistance genes are not yet completely understood. The aminoglycosides are a historically important class of antibiotics that were introduced in the 1940s. Aminoglycoside resistance is conferred most commonly through enzymatic modification of the drug or enzymatic modification of the target rRNA through methylation or through the overexpression of efflux pumps. In our recent paper, we reported that expression of the aminoglycoside resistance genes encoding the aminoglycoside acetyl transferase (AAC) and aminoglycoside adenyl transferase (AAD) enzymes was controlled by an aminoglycoside-sensing riboswitch RNA. This riboswitch is embedded in the leader RNA of the aac/aad genes and is associated with the integron cassette system. The leader RNA can sense and bind specific aminoglycosides such that the binding causes a structural transition in the leader RNA, which leads to the induction of aminoglycoside antibiotic resistance. Specific aminoglycosides induce reporter gene expression mediated by the leader RNA. Aminoglycoside RNA binding was measured directly and, aminoglycoside-induced changes in RNA structure monitored by chemical probing. UV cross-linking and mutational analysis identified potential aminoglycoside binding sites on the RNA.

  16. Glucose-induced expression of MIP-1 genes requires O-GlcNAc transferase in monocytes

    SciTech Connect

    Chikanishi, Toshihiro; Fujiki, Ryoji; Hashiba, Waka; Sekine, Hiroki; Yokoyama, Atsushi; Kato, Shigeaki

    2010-04-16

    O-glycosylation has emerged as an important modification of nuclear proteins, and it appears to be involved in gene regulation. Recently, we have shown that one of the histone methyl transferases (MLL5) is activated through O-glycosylation by O-GlcNAc transferase (OGT). Addition of this monosaccharide is essential for forming a functional complex. However, in spite of the abundance of OGT in the nucleus, the impact of nuclear O-glycosylation by OGT remains largely unclear. To address this issue, the present study was undertaken to test the impact of nuclear O-glycosylation in a monocytic cell line, THP-1. Using a cytokine array, MIP-1{alpha} and -1{beta} genes were found to be regulated by nuclear O-glycosylation. Biochemical purification of the OGT interactants from THP-1 revealed that OGT is an associating partner for distinct co-regulatory complexes. OGT recruitment and protein O-glycosylation were observed at the MIP-1{alpha} gene promoter; however, the known OGT partner (HCF-1) was absent when the MIP-1{alpha} gene promoter was not activated. From these findings, we suggest that OGT could be a co-regulatory subunit shared by functionally distinct complexes supporting epigenetic regulation.

  17. Madumycin II inhibits peptide bond formation by forcing the peptidyl transferase center into an inactive state

    PubMed Central

    Osterman, Ilya A.; Khabibullina, Nelli F.; Komarova, Ekaterina S.; Kasatsky, Pavel; Kartsev, Victor G.; Bogdanov, Alexey A.; Dontsova, Olga A.

    2017-01-01

    Abstract The emergence of multi-drug resistant bacteria is limiting the effectiveness of commonly used antibiotics, which spurs a renewed interest in revisiting older and poorly studied drugs. Streptogramins A is a class of protein synthesis inhibitors that target the peptidyl transferase center (PTC) on the large subunit of the ribosome. In this work, we have revealed the mode of action of the PTC inhibitor madumycin II, an alanine-containing streptogramin A antibiotic, in the context of a functional 70S ribosome containing tRNA substrates. Madumycin II inhibits the ribosome prior to the first cycle of peptide bond formation. It allows binding of the tRNAs to the ribosomal A and P sites, but prevents correct positioning of their CCA-ends into the PTC thus making peptide bond formation impossible. We also revealed a previously unseen drug-induced rearrangement of nucleotides U2506 and U2585 of the 23S rRNA resulting in the formation of the U2506•G2583 wobble pair that was attributed to a catalytically inactive state of the PTC. The structural and biochemical data reported here expand our knowledge on the fundamental mechanisms by which peptidyl transferase inhibitors modulate the catalytic activity of the ribosome. PMID:28505372

  18. Characterisation of the Candida albicans Phosphopantetheinyl Transferase Ppt2 as a Potential Antifungal Drug Target

    PubMed Central

    Dobb, Katharine S.; Kaye, Sarah J.; Beckmann, Nicola; Thain, John L.; Stateva, Lubomira; Birch, Mike; Oliver, Jason D.

    2015-01-01

    Antifungal drugs acting via new mechanisms of action are urgently needed to combat the increasing numbers of severe fungal infections caused by pathogens such as Candida albicans. The phosphopantetheinyl transferase of Aspergillus fumigatus, encoded by the essential gene pptB, has previously been identified as a potential antifungal target. This study investigated the function of its orthologue in C. albicans, PPT2/C1_09480W by placing one allele under the control of the regulatable MET3 promoter, and deleting the remaining allele. The phenotypes of this conditional null mutant showed that, as in A. fumigatus, the gene PPT2 is essential for growth in C. albicans, thus fulfilling one aspect of an efficient antifungal target. The catalytic activity of Ppt2 as a phosphopantetheinyl transferase and the acyl carrier protein Acp1 as a substrate were demonstrated in a fluorescence transfer assay, using recombinant Ppt2 and Acp1 produced and purified from E.coli. A fluorescence polarisation assay amenable to high-throughput screening was also developed. Therefore we have identified Ppt2 as a broad-spectrum novel antifungal target and developed tools to identify inhibitors as potentially new antifungal compounds. PMID:26606674

  19. Glutathione S-transferase alpha 1 risk polymorphism and increased bilateral thalamus mean diffusivity in schizophrenia.

    PubMed

    Spalletta, Gianfranco; Piras, Fabrizio; Gravina, Paolo; Bello, Mario Lo; Bernardini, Sergio; Caltagirone, Carlo

    2012-01-01

    Oxidative damage in brain cells is one of the factors hypothesized to be involved in the pathogenesis of schizophrenia. Glutathione S-transferase (GST) A1*B polymorphism, a genotype associated with a higher risk of oxidative damage, is associated with increased frequency of schizophrenia diagnosis. Thus, here we studied Glutathione S-transferase (GST) A1 polymorphism and diffusion tensor imaging-mean diffusivity (MD) data on deep grey matter brain structures in 56 patients with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revised (DSM-IV-TR) schizophrenia. Clinical diagnosis and psychopathological symptom severity were assessed by using the Structured Clinical Interview for DSM-IV-TR (SCID-P) and the Scales for Assessment of Positive and Negative Symptoms (SAPS and SANS). Results confirmed that patients with schizophrenia who were carriers of the GSTA1 *B risk allele had an increased MD in bilateral thalami and increased severity of auditory and global hallucinations in comparison with non-B carriers. Thus, oxidative stress associated factors may be implicated in specific mechanisms of schizophrenia such as altered microstructure of the thalami and specific psychopathological features of auditory hallucinations.

  20. Copper-Induced Inactivation of Camel Liver Glutathione S-Transferase.

    PubMed

    Ahmed, Anwar; Malik, Ajamaluddin; Jagirdar, Haseeb; Rabbani, Nayyar; Khan, Mohd Shahnawaz; Al-Senaidy, Abdulrahman M; Ismael, Mohamed A

    2016-01-01

    Glutathione S-transferases (GSTs) are multifunctional enzymes and play an important role in detoxification of xenobiotics and protection against oxidative stress. Camel liver glutathione transferase (cGST) was recently isolated and characterized in our lab. In this study, we have evaluated the effect of monovalent, divalent, and trivalent cations on its activity and stability. Cu(++) was found to be the potent inhibitor of GST activity which loses complete activity at 0.5-mM concentration. Other metal ions did not inhibit GST even at higher concentration of 2 mM. GST incubated with Cu(++) (0.1 mM) resulted decrease in free sulfhydryl groups by 55%, whereas other metal ions did not show any effect on free thiol content. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed formation of GST aggregates instantly in the presence of Cu(++), which further increased in molecular size with increase in time of incubation. DTT treatment resulted in de-aggregation of GST oligomers to its monomeric form. However, the GST activity was not recovered completely after de-aggregation. Cu(++) was found to inhibit GST activity by accelerating the inter- and intra-disulfide bond formation. Far-UV circular dichroism (CD) results showed that Cu(++)-catalyzed air oxidation of sulfhydryl groups leads to minor conformational changes in the GST.

  1. Nicotinamide Mononucleotide Adenylyl Transferase 2: A Promising Diagnostic and Therapeutic Target for Colorectal Cancer

    PubMed Central

    Cui, Chunhui; Qi, Jia; Deng, Quanwen; Chen, Rihong; Zhai, Duanyang; Yu, Jinlong

    2016-01-01

    Colorectal cancer (CRC) is one of the most common cancers all over the world. It is essential to search for more effective diagnostic and therapeutic methods for CRC. Abnormal nicotinamide adenine dinucleotide (NAD) metabolism has been considered as a characteristic of cancer cells. In this study, nicotinamide mononucleotide adenylyl transferases (NMNATs) as well as p53-mediated cancer signaling pathways were investigated in patients with colorectal cancer. The CRC tissues and adjacent normal tissues were obtained from 95 untreated colorectal cancer patients and were stained for expression of nicotinamide mononucleotide adenylyl transferase 2 (NMNAT2) and p53. The survival rate was analyzed by the Kaplan-Meier method and the log-rank test. The multivariate Cox proportional hazard regression analysis was conducted as well. Our data demonstrated that expression of NMNAT2 and p53 was significantly higher in CRC tissues, while NMNAT2 expression is in correlation with the invasive depth of tumors and TNM stage. Significant positive correlation was found between the expression of NMNAT2 and the expression of p53. However, NMNAT2 expression was not a statistically significant prognostic factor for overall survival. In conclusion, our results indicated that NMNAT2 might participate in tumorigenesis of CRC in a p53-dependent manner and NMNAT2 expression might be a potential therapeutic target for CRC. PMID:27218101

  2. STT3, a highly conserved protein required for yeast oligosaccharyl transferase activity in vivo.

    PubMed Central

    Zufferey, R; Knauer, R; Burda, P; Stagljar, I; te Heesen, S; Lehle, L; Aebi, M

    1995-01-01

    N-linked glycosylation is a ubiquitous protein modification, and is essential for viability in eukaryotic cells. A lipid-linked core-oligosaccharide is assembled at the membrane of the endoplasmic reticulum and transferred to selected asparagine residues of nascent polypeptide chains by the oligosaccharyl transferase (OTase) complex. Based on the synthetic lethal phenotype of double mutations affecting the assembly of the lipid-linked core-oligosaccharide and the OTase activity, we have performed a novel screen for mutants in Saccharomyces cerevisiae with altered N-linked glycosylation. Besides novel mutants deficient in the assembly of the lipid-linked oligosaccharide (alg mutants), we identified the STT3 locus as being required for OTase activity in vivo. The essential STT3 protein is approximately 60% identical in amino acid sequence to its human homologue. A mutation in the STT3 locus affects substrate specificity of the OTase complex in vivo and in vitro. In stt3-3 cells very little glycosyl transfer occurs from incomplete lipid-linked oligosaccharide, whereas the transfer of full-length Glc3Man9GlcNAc2 is hardly affected as compared with wild-type cells. Depletion of the STT3 protein results in loss of transferase activity in vivo and a deficiency in the assembly of OTase complex. Images PMID:7588624

  3. Vaccination of buffaloes with Fasciola gigantica recombinant glutathione S-transferase and fatty acid binding protein.

    PubMed

    Kumar, Niranjan; Anju, Varghese; Gaurav, Nagar; Chandra, Dinesh; Samanta, S; Gupta, S C; Adeppa, J; Raina, O K

    2012-01-01

    Fasciola gigantica, causative agent of tropical fasciolosis, inflicts substantial economic losses on the livestock industry, affecting severely buffalo productivity in the tropical countries. Very few vaccination trials with different target antigens against F. gigantica infection have been conducted in this host. Present study describes a vaccination trial in buffaloes with F. gigantica recombinant glutathione S-transferase and fatty acid binding protein. The two recombinant proteins were expressed in Escherichia coli and evaluated for their immunoprophylactic potential in buffalo calves, using montanide 70 M-VG, a mineral oil-based adjuvant, for delivering the antigens. Buffalo calves were distributed in three groups, with group I, II and III calves immunized with recombinant glutathione S-transferase, fatty acid binding protein and a cocktail of these two antigens, respectively. Immunization of the calves evoked a mixed IgG1 and IgG2 antibody response. Present vaccination trial in these animals achieved a maximum protection level of 35%, when the two antigens were used in combination. Eosinophils were measured in both immunized and non-immunized challenge control animals, which showed a steady increase in their count in response to immunization with both the antigens and infection with F. gigantica, respectively.

  4. Affinity labeling of a reactive sulfhydryl residue at the peptidyl transferase P site in Drosophila ribosomes.

    PubMed

    Fabijanski, S; Pellegrini, M

    1979-12-11

    An affinity label has been prepared that is specific for the P site of a eucaryotic peptidyl transferase, that of Drosophila melanogaster. It has the sequence C-A-C-C-A-(Ac[3H]Leu) with a mercury atom added at the C-5 position of all three cytosine residues (referred to as the mercurated fragment). This label is an analogue of the 3' terminus of N-acetylleucyl-tRNA. The mercurated fragment binds specifically to the P site of peptidyl transferase. It participates fully in peptide bond formation as judged by its ability to transfer N-acetylleucine to puromycin with at least the same efficiency as a nonmercurated fragment. Once bound to the P site, the mercurated fragment reacts covalently with a ribosomal protein(s). This affinity-labeling process can be effectively competed by nonmercurated fragment, which indicates a site-specific reaction. The covalent attachment of the affinity label to a ribosomal protein(s) occurs through the formation of a mercury-sulfur bond, as judged by its lability in the presence of thiol reducing agents. The major ribosomal protein labeled at the P site of D. melanogaster was found to be a small, basic protein. The electrophoretic behavior of this protein parallels that of major P site proteins found in Escherichia coli ribosomes and in other eucaryotes. These results suggest conservation of some of the overall properties of the P site proteins from these organisms.

  5. Endothelial cell palmitoylproteomics identifies novel lipid modified targets and potential substrates for protein acyl transferases

    PubMed Central

    Marin, Ethan P.; Derakhshan, Behrad; Lam, TuKiet T.; Davalos, Alberto; Sessa, William C.

    2012-01-01

    Rationale Protein S-palmitoylation is the post-translational attachment of a saturated 16-carbon palmitic acid to a cysteine side chain via a thioester bond. Palmitoylation can affect protein localization, trafficking, stability, and function. The extent and roles of palmitoylation in endothelial cell (EC) biology is not well understood, in part due to technological limits on palmitoylprotein detection. Objective To develop a method using acyl-biotinyl exchange (ABE) technology coupled with mass spectrometry to globally isolate and identify palmitoylproteins in EC. Methods and Results More than 150 putative palmitoyl proteins were identified in EC using ABE and mass spectrometry. Among the novel palmitoylproteins identified is superoxide dismutase 1 (SOD1), an intensively studied enzyme that protects all cells from oxidative damage. Mutation of cysteine 6 prevents palmitoylation, leads to reduction in SOD1 activity in vivo and in vitro, and inhibits nuclear localization, thereby supporting a functional role for SOD1 palmitoylation. Moreover, we used ABE to search for substrates of particular protein acyl transferases in EC. We found that palmitoylation of the cell adhesion protein PECAM1 is dependent on the protein acyl transferase ZDHHC21. We show that knockdown of ZDHHC21 leads to reduced levels of PECAM1 at the cell surface. Conclusions Our data demonstrate the utility of EC palmitoylproteomics to reveal new insights into the role of this important post-translational lipid modification in EC biology. PMID:22496122

  6. Characterization of glutathione S-transferase from dwarf pine needles (Pinus mugo Turra).

    PubMed

    Schröder, P; Rennenberg, H

    1992-09-01

    Glutathione S-transferase activity conjugating xenobiotics with glutathione (GSH) was found in extracts from needles of dwarf pine (Pinus mugo Turra). In vivo incubation of needle segments with the herbicide fluorodifen at 25 degrees C resulted in conversion of the xenobiotic to water-soluble products at initial rates of 0.7 nmol h(-1) g(fw) (-1). At 15 degrees C, the initial rate of product formation was decreased to 0.1 nmol h(-1) g(fw) (-1). In vitro conjugation studies with chloro-2,4-dinitrobenzene (CDNB) and 1,2-dichloro-4-nitrobenzene (DCNB) as model substrates gave apparent K(m) values of 0.5 mM GSH and 1.14 mM CDNB in the GSH/CDNB system and 0.3 mM GSH and 0.44 mM DCNB in the GSH/DCNB system. The pH optimum was between 7.7 and 7.9 for both the GSH/CDNB and the GSH/DCNB systems. The temperature optimum for these model substrates was between 30 and 35 degrees C, and only minute amounts of enzyme activity were detected at 15 degrees C. The activation energy in the temperature range of 15 to 30 degrees C was 46 kJ mol(-1). Dwarf pine glutathione S-transferase exhibited an approximate molecular weight of 52 kD.

  7. A strategy to discover inhibitors of Bacillus subtilis surfactin-type phosphopantetheinyl transferase.

    PubMed

    Yasgar, Adam; Foley, Timothy L; Jadhav, Ajit; Inglese, James; Burkart, Michael D; Simeonov, Anton

    2010-02-01

    Surfactin-type phosphopantetheinyl transferases (Sfp-PPTases) are responsible for modifying type I polyketide and non-ribosomal peptide synthases of prokaryotes and have been implicated in the activation of a variety of pathogen-associated virulence factors. As such, inhibitors of this enzyme class represent enticing leads for antibiotic development and can serve as tools in studies of bacterial metabolism. Currently, no small molecule inhibitors of Sfp-PPTase are known, highlighting the need for efficient methods for PPTase inhibitor identification and development. Herein, we present the design and implementation of a robust and miniaturized high-throughput kinetic assay for inhibitors of Sfp-PPTase using the substrate combination of rhodamine-labeled coenzyme A and Black Hole Quencher-2 labeled consensus acceptor peptide YbbR. Upon PPTase-catalyzed transfer of the rhodamine-labeled phosphopantetheinyl arm onto the acceptor peptide, the fluorescent donor and quencher are covalently joined and the fluorescence signal is reduced. This assay was miniaturized to a low 4 microL volume in 1536-well format and was used to screen the library of pharmacologically active compounds (LOPAC(1280)). Top inhibitors identified by the screen were further characterized in secondary assays, including protein phosphopantetheinylation detected by gel electrophoresis. The present assay enables the screening of large compound libraries against Sfp-PPTase in a robust and automated fashion and is applicable to designing assays for related transferase enzymes.

  8. Purification and characterization of a labile rat glutathione transferase of the Mu class.

    PubMed Central

    Kispert, A; Meyer, D J; Lalor, E; Coles, B; Ketterer, B

    1989-01-01

    A labile GSH transferase homodimer termed 11-11 was purified from rat testis by GSH-agarose affinity chromatography followed by anion-exchange f.p.l.c. The enzyme is unstable in the absence of thiol(s) and has relatively low affinity for both 1-chloro-2,4-dinitrobenzene (Km 4.4 mM) and GSH (Km(app.) 4.4mM). Its mobility on SDS/polyacrylamide-gel electrophoresis is slightly less than that of subunits 3 and 4 and its pI is 5.2. Subunit 11 has a blocked N-terminal amino acid residue, but after CNBr cleavage fragments accounting for 113 amino acid residues were sequenced and showed 65% homology with corresponding sequences in subunit 4, indicating that it is a member of the Mu family. GSH transferase 11 is a major isoenzyme in testis, epididymis, prostate and brain and present at lower concentrations in other tissues. Images Fig. 3. Fig. 4. PMID:2764905

  9. Characterization of a Bvg-regulated fatty acid methyl-transferase in Bordetella pertussis

    PubMed Central

    Rivera-Millot, Alex; Lesne, Elodie; Solans, Luis; Coutte, Loic; Bertrand-Michel, Justine; Froguel, Philippe; Dhennin, Véronique; Hot, David; Locht, Camille; Antoine, Rudy

    2017-01-01

    The whooping cough agent Bordetella pertussis controls the expression of its large virulence regulon in a coordinated manner through the two-component signal transduction system BvgAS. In addition to the genes coding for bona fide virulence factors, the Bvg regulon comprises genes of unknown function. In this work, we characterized a new Bvg-activated gene called BP2936. Homologs of BP2936 are found in other pathogenic Bordetellae and in several other species, including plant pathogens and environmental bacteria. We showed that the gene product of BP2936 is a membrane-associated methyl-transferase of free fatty acids. We thus propose to name it FmtB, for fatty acid methyl-transferase of Bordetella. The role of this protein was tested in cellular and animal models of infection, but the loss of BP2936 did not appear to affect host-pathogen interactions in those assays. The high level of conservation of BP2936 among B. pertussis isolates nevertheless argues that it probably plays a role in the life cycle of this pathogen. PMID:28493897

  10. Functional Diversification of Fungal Glutathione Transferases from the Ure2p Class

    PubMed Central

    Thuillier, Anne; Ngadin, Andrew A.; Thion, Cécile; Billard, Patrick; Jacquot, Jean-Pierre; Gelhaye, Eric; Morel, Mélanie

    2011-01-01

    The glutathione-S-transferase (GST) proteins represent an extended family involved in detoxification processes. They are divided into various classes with high diversity in various organisms. The Ure2p class is especially expanded in saprophytic fungi compared to other fungi. This class is subdivided into two subclasses named Ure2pA and Ure2pB, which have rapidly diversified among fungal phyla. We have focused our analysis on Basidiomycetes and used Phanerochaete chrysosporium as a model to correlate the sequence diversity with the functional diversity of these glutathione transferases. The results show that among the nine isoforms found in P. chrysosporium, two belonging to Ure2pA subclass are exclusively expressed at the transcriptional level in presence of polycyclic aromatic compounds. Moreover, we have highlighted differential catalytic activities and substrate specificities between Ure2pA and Ure2pB isoforms. This diversity of sequence and function suggests that fungal Ure2p sequences have evolved rapidly in response to environmental constraints. PMID:22164343

  11. Miners compensated for pneumoconiosis and glutathione s-transferases M1 and T1 genotypes.

    PubMed

    Zimmermann, Anna; Ebbinghaus, Rainer; Prager, Hans-Martin; Blaszkewicz, Meinolf; Hengstler, Jan G; Golka, Klaus

    2012-01-01

    Chronic inhalation of quartz-containing dust produces reversible inflammatory changes in lungs resulting in irreversible fibrotic changes termed pneumoconiosis. Due to the inflammatory process in the lungs, highly reactive substances are released that may be detoxified by glutathione S-transferases. Therefore, 90 hard coal miners with pneumoconiosis as a recognized occupational disease (in Germany: Berufskrankheit BK 4101) were genotyped for glutathione S-transferases M1 (GSTM1) and T1 (GSTT1) according to standard methods. Furthermore, occupational exposure and smoking habits were assessed by questionnaire. Changes in a chest x-ray were classified according to ILO classification 2000. Of the investigated hard coal miners 43% were GSTM1 negative whereas 57% were GSTM1 positive. The arithmetic mean of the age at time of investigation was 74.2 yr (range: 42-87 yr). Seventy-four percent of the hard coal miners reported being ever smokers, while 26% denied smoking. All hard coal miners provided pneumoconiosis-related changes in the chest x-ray. The observed frequency of GSTM1 negative hard coal miners was not different from frequencies reported for general Caucasian populations and in agreement with findings reported for Chinese coal miners. In contrast, in a former study, 16 of 19 German hard coal miners (84%) with urinary bladder cancer displayed a GSTM1 negative genotype. The outcome of this study provides evidence that severely occupationally exposed Caucasian hard coal miners do not present an elevated level of GSTM1 negative individuals.

  12. Structure of a lipid A phosphoethanolamine transferase suggests how conformational changes govern substrate binding.

    PubMed

    Anandan, Anandhi; Evans, Genevieve L; Condic-Jurkic, Karmen; O'Mara, Megan L; John, Constance M; Phillips, Nancy J; Jarvis, Gary A; Wills, Siobhan S; Stubbs, Keith A; Moraes, Isabel; Kahler, Charlene M; Vrielink, Alice

    2017-02-28

    Multidrug-resistant (MDR) gram-negative bacteria have increased the prevalence of fatal sepsis in modern times. Colistin is a cationic antimicrobial peptide (CAMP) antibiotic that permeabilizes the bacterial outer membrane (OM) and has been used to treat these infections. The OM outer leaflet is comprised of endotoxin containing lipid A, which can be modified to increase resistance to CAMPs and prevent clearance by the innate immune response. One type of lipid A modification involves the addition of phosphoethanolamine to the 1 and 4' headgroup positions by phosphoethanolamine transferases. Previous structural work on a truncated form of this enzyme suggested that the full-length protein was required for correct lipid substrate binding and catalysis. We now report the crystal structure of a full-length lipid A phosphoethanolamine transferase from Neisseria meningitidis, determined to 2.75-Å resolution. The structure reveals a previously uncharacterized helical membrane domain and a periplasmic facing soluble domain. The domains are linked by a helix that runs along the membrane surface interacting with the phospholipid head groups. Two helices located in a periplasmic loop between two transmembrane helices contain conserved charged residues and are implicated in substrate binding. Intrinsic fluorescence, limited proteolysis, and molecular dynamics studies suggest the protein may sample different conformational states to enable the binding of two very different- sized lipid substrates. These results provide insights into the mechanism of endotoxin modification and will aid a structure-guided rational drug design approach to treating multidrug-resistant bacterial infections.

  13. Tomatidine, a tomato sapogenol, ameliorates hyperlipidemia and atherosclerosis in apoE-deficient mice by inhibiting acyl-CoA:cholesterol acyl-transferase (ACAT).

    PubMed

    Fujiwara, Yukio; Kiyota, Naoko; Tsurushima, Keiichiro; Yoshitomi, Makiko; Horlad, Hasita; Ikeda, Tsuyoshi; Nohara, Toshihiro; Takeya, Motohiro; Nagai, Ryoji

    2012-03-14

    It was previously revealed that esculeoside A, a new glycoalkaloid, and esculeogenin A, a new aglycon of esculeoside A, contained in ripe tomato ameliorate atherosclerosis in apoE-deficent mice. This study examined whether tomatidine, the aglycone of tomatine, which is a major tomato glycoalkaloid, also shows similar inhibitory effects on cholesterol ester (CE) accumulation in human monocyte-derived macrophages (HMDM) and atherogenesis in apoE-deficient mice. Tomatidine significantly inhibited the CE accumulation induced by acetylated LDL in HMDM in a dose-dependent manner. Tomatidine also inhibited CE formation in Chinese hamster ovary cells overexpressing acyl-CoA:cholesterol acyl-transferase (ACAT)-1 or ACAT-2, suggesting that tomatidine suppresses both ACAT-1 and ACAT-2 activities. Furthermore, the oral administration of tomatidine to apoE-deficient mice significantly reduced levels of serum cholesterol, LDL-cholesterol, and areas of atherosclerotic lesions. The study provides the first evidence that tomatidine significantly suppresses the activity of ACAT and leads to reduction of atherogenesis.

  14. Chloroform inhibits the development of diethylnitrosamine-initiated, phenobarbital-promoted gamma-glutamyltranspeptidase and placental form glutathione S-transferase-positive foci in rat liver.

    PubMed

    Reddy, T V; Daniel, F B; Lin, E L; Stober, J A; Olson, G R

    1992-08-01

    In this study we demonstrate that chloroform, a widely used industrial solvent, a medicinal chemical and a common drinking water contaminant, reduces the number of detectable preneoplastic enzyme-altered foci [gamma-glutamyltranspeptidase-positive (GGT+) and placental form glutathione S-transferase-positive (GST-P+)] in the liver of male Fischer 344 rats. The animals were given a partial hepatectomy and 18 h later received a single oral dose of either 0.5 mmol/kg diethylnitrosamine (DENA) or saline. Two weeks later, groups of 12 animals were started on drinking water containing phenobarbital with varying concentrations (200-1800 mg/l) of chloroform fro 12 weeks. Treated and control animals were killed and the number and the volume of GGT+ and GST-P+ expressing hepatic foci were tabulated. The numbers of foci per unit volume (and per unit area), the percent focal volume and the focal liver were reduced by chloroform in a dose-dependent manner. The mean focal volume was not influenced by chloroform. A plausible explanation for these results could be that chloroform exerts its focal inhibitory effect either by selectively killing the putative initiated cells, by retarding the inherent growth rate of enzyme-altered cells or by reducing the effectiveness of the promoter, phenobarbital. The available evidence suggests that the first hypothesis is the most likely explanation for these observations. These results are consistent with earlier studies showing that chloroform inhibits tumorigenesis in rodents.

  15. Null genotypes of glutathione S-transferase μ1 and glutathione S-transferase θ1 are associated with osteosarcoma risk: A meta-analysis

    PubMed Central

    HAN, JICHENG; DENG, WEI; WANG, LAIYING; QI, WANLI

    2015-01-01

    Glutathione S-transferase (GST) genetic polymorphisms has been reported to be associated with osteosarcoma; however, the results of previous studies are conflicting. Thus, in the present study, a meta-analysis was conducted to investigate the effects of GSTM1 and GSTT1 polymorphisms on osteosarcoma risk. A literature search was performed in the PubMed, Cochrane Library and China National Knowledge Infrastructure databases to identify case-control studies published prior to March 2014. Data were extracted and pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated. In addition, Begg’s test was used to measure publication bias. Sensitivity analysis were performed to ensure the accuracy of the results. The meta-analysis results demonstrated no significant association between the null genotype of GSTM1 and osteosarcoma risk (OR=0.83; 95% CI, 0.37–1.85). By contrast, the results revealed a significant association for the comparison of null vs. non-null genotypes of GSTT1 (OR=1.54; 95% CI, 1.09–2.19). In conclusion, the GSTT1 null genotype may be associated with an increased risk of developing osteosarcoma. Further studies with larger sample sizes and well-designed methodologies are required to verify these conclusions. PMID:25789067

  16. Human liver glutathione S-transferase psi. Chemical characterization and secondary-structure comparison with other mammalian glutathione S-transferases.

    PubMed Central

    Singh, S V; Kurosky, A; Awasthi, Y C

    1987-01-01

    The isolation and chemical characterization of the anionic human liver glutathione S-transferase (GST) psi (pI 5.5) are described and compared with other GST isoenzymes reported for rat and human. Amino acid compositional analysis, substrate specificity and isoelectric focusing indicated that GST psi is a unique isoenzyme form of GST. Strikingly, however, amino acid sequence analysis of the N-terminal region indicated that GST psi was identical with GST mu in the first 23 amino acid residues reported. It is likely that these two enzyme forms are at least partially structurally related. In order to investigate further the genetic relationship of GST psi to other reported GST isoenzymes, secondary-structure analysis was performed. Despite substantial differences in the N-terminal-region amino acid sequences of some of the GST isoenzymes, the secondary structure of all the isoenzymes is highly conserved at their N-termini. The general uniformity of the secondary structure of this enzyme class at their N-termini strongly indicated that the observed diversity of these isoenzymes probably occurred as a result of a mechanism of gene duplication followed by divergence rather than a mechanism of convergent evolution. PMID:3606582

  17. Mice Deficient in Glutathione Transferase Zeta/Maleylacetoacetate Isomerase Exhibit a Range of Pathological Changes and Elevated Expression of Alpha, Mu, and Pi Class Glutathione Transferases

    PubMed Central

    Lim, Cindy E.L.; Matthaei, Klaus I.; Blackburn, Anneke C.; Davis, Richard P.; Dahlstrom, Jane E.; Koina, Mark E.; Anders, M.W.; Board, Philip G.

    2004-01-01

    Glutathione transferase zeta (GSTZ1-1) is the major enzyme that catalyzes the metabolism of α-halo acids such as dichloroacetic acid, a carcinogenic contaminant of chlorinated water. GSTZ1-1 is identical with maleylacetoacetate isomerase, which catalyzes the penultimate step in the catabolic pathways for phenylalanine and tyrosine. In this study we have deleted the Gstz1 gene in BALB/c mice and characterized their phenotype. Gstz1−/− mice do not have demonstrable activity with maleylacetone and α-halo acid substrates, and other GSTs do not compensate for the loss of this enzyme. When fed a standard diet, the GSTZ1-1-deficient mice showed enlarged liver and kidneys as well as splenic atrophy. Light and electron microscopic examination revealed multifocal hepatitis and ultrastructural changes in the kidney. The addition of 3% (w/v) phenylalanine to the drinking water was lethal for young mice (<28 days old) and caused liver necrosis, macrovesicular steatosis, splenic atrophy, and a significant loss of circulating leukocytes in older surviving mice. GSTZ1-1-deficient mice showed constitutive induction of alpha, mu, and pi class GSTs as well as NAD(P)H:quinone oxidoreductase 1. The overall response is consistent with the chronic accumulation of a toxic metabolite(s). We detected the accumulation of succinylacetone in the serum of deficient mice but cannot exclude the possibility that maleylacetoacetate and maleylacetone may also accumulate. PMID:15277241

  18. Biosynthesis of osmoregulated periplasmic glucans in Escherichia coli: the phosphoethanolamine transferase is encoded by opgE.

    PubMed

    Bontemps-Gallo, Sébastien; Cogez, Virginie; Robbe-Masselot, Catherine; Quintard, Kevin; Dondeyne, Jacqueline; Madec, Edwige; Lacroix, Jean-Marie

    2013-01-01

    Osmoregulated periplasmic glucans (OPGs) are oligosaccharides found in the periplasm of many Gram-negative bacteria. Glucose is the sole constitutive sugar and this backbone may be substituted by various kinds of molecules depending on the species. In E. coli, OPG are substituted by phosphoglycerol and phosphoethanolamine derived from membrane phospholipids and by succinyl residues. In this study, we describe the isolation of the opgE gene encoding the phosphoethanolamine transferase by a screen previously used for the isolation of the opgB gene encoding the phosphoglycerol transferase. Both genes show structural and functional similarities without sequence similarity.

  19. Biosynthesis of Osmoregulated Periplasmic Glucans in Escherichia coli: The Phosphoethanolamine Transferase Is Encoded by opgE

    PubMed Central

    Bontemps-Gallo, Sébastien; Robbe-Masselot, Catherine; Quintard, Kevin; Dondeyne, Jacqueline; Madec, Edwige

    2013-01-01

    Osmoregulated periplasmic glucans (OPGs) are oligosaccharides found in the periplasm of many Gram-negative bacteria. Glucose is the sole constitutive sugar and this backbone may be substituted by various kinds of molecules depending on the species. In E. coli, OPG are substituted by phosphoglycerol and phosphoethanolamine derived from membrane phospholipids and by succinyl residues. In this study, we describe the isolation of the opgE gene encoding the phosphoethanolamine transferase by a screen previously used for the isolation of the opgB gene encoding the phosphoglycerol transferase. Both genes show structural and functional similarities without sequence similarity. PMID:24228245

  20. Bioanalysis of farnesyl pyrophosphate in human plasma by high-performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry and hybrid quadrupole Orbitrap high-resolution mass spectrometry.

    PubMed

    Sugimoto, Hiroshi; Iguchi, Mie; Jinno, Fumihiro

    2017-05-01

    The isoprenoids farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) are pivotal intermediates for cholesterol homeostasis and cell signaling in the mevalonate pathway. We developed a sensitive and selective high-performance liquid chromatography tandem triple quadrupole mass spectrometry (LC-QQQ-MS) method for FPP in human plasma without the need for a derivatization process. We optimized the sample preparation procedure to extract FPP and (13)C5-FPP (as internal standard) from sample fluids using methanol. Phosphate-buffered saline was used as the surrogate matrix for the preparation of calibration curves and quality control samples. Using an XBridge C18 column (3.5 μm, 2.1 × 100-mm ID) with gradient elution composed of 10 mmol/L ammonium carbonate/ammonium hydroxide (1000:5, v/v) and acetonitrile/ammonium hydroxide (1000:5, v/v) provided the sharp peaks of FPP and (13)C5-FPP in human plasma. The calibration curve ranged from 0.2 to 20 ng/mL in human plasma with acceptable intra-day and inter-day precision and accuracy. The sensitivity of this bioanalytical method was sufficient for clinical analysis. The endogenous FPP plasma concentrations in 40 human healthy volunteers ascertained by LC-QQQ-MS and high-performance liquid chromatography tandem hybrid quadrupole Orbitrap high-resolution mass spectrometry (LC-Q-Orbi-MS) were comparable. Furthermore, the endogenous GGPP in human plasma was selectively detected for the first time by LC-Q-Orbi-MS. In conclusion, a sensitive bioanalytical method for FPP in human plasma by means of LC-QQQ-MS and LC-Q-Orbi-MS was developed in this study. Taking into account the versatility of LC-Q-Orbi-MS, the simultaneous detection of FPP and GGPP may be feasible in clinical practice.

  1. Structure of 2C-methyl-D-erythritol-2,4-cyclodiphosphate synthase from Shewanella oneidensis at 1.6 A: identification of farnesyl pyrophosphate trapped in a hydrophobic cavity.

    PubMed

    Ni, Shuisong; Robinson, Howard; Marsing, Gregory C; Bussiere, Dirksen E; Kennedy, Michael A

    2004-11-01

    Isopentenyl pyrophosphate (IPP) is a universal building block for the ubiquitous isoprenoids that are essential to all organisms. The enzymes of the non-mevalonate pathway for IPP synthesis, which is unique to many pathogenic bacteria, have recently been explored as targets for antibiotic development. Several crystal structures of 2C-methyl-D-erythritol-2,4-cyclophosphate (MECDP) synthase, the fifth of seven enzymes involved in the non-mevalonate pathway for synthesis of IPP, have been reported; however, the composition of metal ions in the active site and the presence of a hydrophobic cavity along the non-crystallographic threefold symmetry axis has varied between the reported structures. Here, the structure of MEDCP from Shewanella oneidensis MR1 (SO3437) was determined to 1.6 A resolution in the absence of substrate. The presence of a zinc ion in the active-site cleft, tetrahedrally coordinated by two histidine side chains, an aspartic acid side chain and an ambiguous fourth ligand, was confirmed by zinc anomalous diffraction. Based on analysis of anomalous diffraction data and typical metal-to-ligand bond lengths, it was concluded that an octahedral sodium ion was 3.94 A from the zinc ion. A hydrophobic cavity was observed along the threefold non-crystallographic symmetry axis, filled by a well defined non-protein electron density that could be modeled as farnesyl pyrophosphate (FPP), a downstream product of IPP, suggesting a possible feedback mechanism for enzyme regulation. The high-resolution data clarified the FPP-binding mode compared with previously reported structures. Multiple sequence alignment indicated that the residues critical to the formation of the hydrophobic cavity and for coordinating the pyrophosphate group of FPP are present in the majority of MEDCP synthase enzymes, supporting the idea of a specialized biological function related to FPP binding in a subfamily of MEDCP synthase homologs.

  2. Simvastatin prevents β-amyloid(25-35)-impaired neurogenesis in hippocampal dentate gyrus through α7nAChR-dependent cascading PI3K-Akt and increasing BDNF via reduction of farnesyl pyrophosphate.

    PubMed

    Wang, Conghui; Chen, Tingting; Li, Guoxi; Zhou, Libin; Sha, Sha; Chen, Ling

    2015-10-01

    Simvastatin (SV) is reported to improve cognition and slow progression of Alzheimer's disease (AD), however underlying mechanism still remains unclear. In hippocampal dentate gyrus (DG), β-amyloid (Aβ) selectively impairs survival and neurite growth of newborn neurons in the 2(nd) week after birth. The aim of this study was to examine the effects of SV on the impairment of neurogenesis and the spatial cognitive deficits in Aβ25-35 (3 nmol)-injected (i.c.v.) mice (Aβ25-35-mice). Herein, we reported that the SV-treatment (20 mg/kg) on days 2-14 after BrdU-injection could dose-dependently protect the survival and neurite growth of newborn neurons, which was blocked by the α7nAChR antagonist MLA or the farnesol (FOH) that can convert to farnesyl pyrophosphate (FPP), but not the α4β2nAChR antagonist DHβE. The SV-treatment in Aβ25-35-mice rescued the decline of Akt phosphorylation and increased the ERK1/2 phosphorylation in hippocampus, which was sensitive to MLA and FOH. The PI3K inhibitor LY294002 could abolish the SV-protected neurogenesis in Aβ25-35-mice, but the MEK inhibitor U0126 had no effects. The SV-treatment could correct the decline of hippocampal BDNF concentration in Aβ25-35-mice, which was blocked by MLA and FOH. Using Morris water maze and Y-maze tasks, we further observed that the SV-treatment in Aβ25-35-mice could improve their spatial cognitive deficits, which was sensitive to the application of FOH. The results indicate that the SV-treatment in Aβ25-35-mice via reduction of FPP can protect neurogenesis through α7nAChR-cascading PI3K-Akt and increasing BDNF, which may improve spatial cognitive function.

  3. Radiation Induced Oral Mucositis

    PubMed Central

    PS, Satheesh Kumar; Balan, Anita; Sankar, Arun; Bose, Tinky

    2009-01-01

    Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i) With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii) who also received concomitant chemotherapy; (iii) who received a total dose over 5,000 cGy; and (iv) who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene PMID:20668585

  4. Paradoxical inhibition of rat glutathione transferase 4-4 by indomethacin explained by substrate-inhibitor-enzyme complexes in a random-order sequential mechanism.

    PubMed Central

    Danielson, U H; Mannervik, B

    1988-01-01

    Under standard assay conditions, with 1-chloro-2,4-dinitrobenzene (CDNB) as electrophilic substrate, rat glutathione transferase 4-4 is strongly inhibited (I50 = 1 microM) by indomethacin. No other glutathione transferase investigated is significantly inhibited by micromolar concentrations of indomethacin. Paradoxically, the strong inhibition of glutathione transferase 4-4 was dependent on high (millimolar) concentrations of CDNB; at low concentrations of this substrate or with other substrates the effect of indomethacin on the enzyme was similar to the moderate inhibition noted for other glutathione transferases. In general, the inhibition of glutathione transferases can be explained by a random-order sequential mechanism, in which indomethacin acts as a competitive inhibitor with respect to the electrophilic substrate. In the specific case of glutathione transferase 4-4 with CDNB as substrate, indomethacin binds to enzyme-CDNB and enzyme-CDNB-GSH complexes with an even greater affinity than to the corresponding complexes lacking CDNB. Under presumed physiological conditions with low concentrations of electrophilic substrates, indomethacin is not specific for glutathione transferase 4-4 and may inhibit all forms of glutathione transferase. PMID:3390138

  5. Glutathione-S-transferase-pi (GST-pi) expression in renal cell carcinoma.

    PubMed

    Kaprilian, Christina; Horti, Maria; Kandilaris, Kosmas; Skolarikos, Andreas; Trakas, Nikolaos; Kastriotis, Ioannis; Deliveliotis, Charalambos

    2015-01-01

    Multidrug resistance correlates with unfavourable treatment outcomes in numerous cancers including renal cell carcinoma. The expression and clinical relevance of Glutathione-S-transferase-pi (GST-pi), a multidrug resistance factor, in kidney tumors remain controversial. We analyzed the expression of GST-pi in 60 formalin-fixed, paraffin-embedded renal cell carcinoma samples by immunohistochemistry and compared them with matched normal regions of the kidney. A significantly higher expression of GST-pi was observed in 87% of clear cell carcinoma and 50% of papillary subtypes. GST-pi expression did not correlate with tumor grade or patient survival. GST-pi is unlikely to be a prognostic factor for renal cell carcinoma. However, further studies with large number of samples are warranted to establish the role of GST-pi, if any, in intrinsic or acquired resistance of renal cell carcinoma to conventional treatments.

  6. SKN-1-independent transcriptional activation of glutathione S-transferase 4 (GST-4) by EGF signaling.

    PubMed

    Detienne, Giel; Van de Walle, Pieter; De Haes, Wouter; Schoofs, Liliane; Temmerman, Liesbet

    2016-01-01

    In C. elegans research, transcriptional activation of glutathione S-transferase 4 (gst-4) is often used as a read-out for SKN-1 activity. While many heed an assumed non-exclusivity of the GFP reporter signal driven by the gst-4 promoter to SKN-1, this is also often ignored. We here show that gst-4 can also be transcriptionally activated by EOR-1, a transcription factor mediating effects of the epidermal growth factor (EGF) pathway. Along with enhancing exogenous oxidative stress tolerance, EOR-1 inde-pendently of SKN-1 increases gst-4 transcription in response to augmented EGF signaling. Our findings caution researchers within the C. elegans community to always rely on sufficient experimental controls when assaying SKN-1 transcriptional activity with a gst-4p::gfp reporter, such as SKN-1 loss-of-function mutants and/or additional target genes next to gst-4.

  7. Glucose regulates mitochondrial motility via Milton modification by O-GlcNAc transferase.

    PubMed

    Pekkurnaz, Gulcin; Trinidad, Jonathan C; Wang, Xinnan; Kong, Dong; Schwarz, Thomas L

    2014-07-03

    Cells allocate substantial resources toward monitoring levels of nutrients that can be used for ATP generation by mitochondria. Among the many specialized cell types, neurons are particularly dependent on mitochondria due to their complex morphology and regional energy needs. Here, we report a molecular mechanism by which nutrient availability in the form of extracellular glucose and the enzyme O-GlcNAc Transferase (OGT), whose activity depends on glucose availability, regulates mitochondrial motility in neurons. Activation of OGT diminishes mitochondrial motility. We establish the mitochondrial motor-adaptor protein Milton as a required substrate for OGT to arrest mitochondrial motility by mapping and mutating the key O-GlcNAcylated serine residues. We find that the GlcNAcylation state of Milton is altered by extracellular glucose and that OGT alters mitochondrial motility in vivo. Our findings suggest that, by dynamically regulating Milton GlcNAcylation, OGT tailors mitochondrial dynamics in neurons based on nutrient availability.

  8. Rab geranylgeranyl transferase β subunit is essential for male fertility and tip growth in Arabidopsis.

    PubMed

    Gutkowska, Malgorzata; Wnuk, Marta; Nowakowska, Julita; Lichocka, Malgorzata; Stronkowski, Michal M; Swiezewska, Ewa

    2015-01-01

    Rab proteins, key players in vesicular transport in all eukaryotic cells, are post-translationally modified by lipid moieties. Two geranylgeranyl groups are attached to the Rab protein by the heterodimeric enzyme Rab geranylgeranyl transferase (RGT) αβ. Partial impairment in this enzyme activity in Arabidopsis, by disruption of the AtRGTB1 gene, is known to influence plant stature and disturb gravitropic and light responses. Here it is shown that mutations in each of the RGTB genes cause a tip growth defect, visible as root hair and pollen tube deformations. Moreover, FM 1-43 styryl dye endocytosis and recycling are affected in the mutant root hairs. Finally, it is demonstrated that the double mutant, with both AtRGTB genes disrupted, is non-viable due to absolute male sterility. Doubly mutated pollen is shrunken, has an abnormal exine structure, and shows strong disorganization of internal membranes, particularly of the endoplasmic reticulum system.

  9. Irreversible Inhibition of Glutathione S-Transferase by Phenethyl Isothiocyanate (PEITC), a Dietary Cancer Chemopreventive Phytochemical

    PubMed Central

    Kumari, Vandana; Dyba, Marzena A.; Holland, Ryan J.; Liang, Yu-He; Singh, Shivendra V.

    2016-01-01

    Dietary isothiocyanates abundant as glucosinolate precursors in many edible cruciferous vegetables are effective for prevention of cancer in chemically-induced and transgenic rodent models. Some of these agents, including phenethyl isothiocyanate (PEITC), have already advanced to clinical investigations. The primary route of isothiocyanate metabolism is its conjugation with glutathione (GSH), a reaction catalyzed by glutathione S-transferase (GST). The pi class GST of subunit type 1 (hGSTP1) is much more effective than the alpha class GST of subunit type 1 (hGSTA1) in catalyzing the conjugation. Here, we report the crystal structures of hGSTP1 and hGSTA1 each in complex with the GSH adduct of PEITC. We find that PEITC also covalently modifies the cysteine side chains of GST, which irreversibly inhibits enzymatic activity. PMID:27684484

  10. Recent advances in protein engineering and biotechnological applications of glutathione transferases.

    PubMed

    Perperopoulou, Fereniki; Pouliou, Fotini; Labrou, Nikolaos E

    2017-09-22

    Glutathione transferases (GSTs, EC 2.5.1.18) are a widespread family of enzymes that play a central role in the detoxification, metabolism, and transport or sequestration of endogenous or xenobiotic compounds. During the last two decades, delineation of the important structural and catalytic features of GSTs has laid the groundwork for engineering GSTs, involving both rational and random approaches, aiming to create new variants with new or altered properties. These approaches have expanded the usefulness of native GSTs, not only for understanding the fundamentals of molecular detoxification mechanisms, but also for the development medical, analytical, environmental, and agricultural applications. This review article attempts to summarize successful examples and current developments on GST engineering, highlighting in parallel the recent knowledge gained on their phylogenetic relationships, structural/catalytic features, and biotechnological applications.

  11. Crystallization and preliminary X-ray analysis of glutathione transferases from cyanobacteria

    PubMed Central

    Feil, Susanne C.; Tang, Julian; Hansen, Guido; Gorman, Michael A.; Wiktelius, Eric; Stenberg, Gun; Parker, Michael W.

    2009-01-01

    Glutathione S-transferases (GSTs) are a group of multifunctional enzymes that are found in animals, plants and microorganisms. Their primary function is to remove toxins derived from exogenous sources or the products of metabolism from the cell. Mammalian GSTs have been extensively studied, in contrast to bacterial GSTs which have received relatively scant attention. A new class of GSTs called Chi has recently been identified in cyanobacteria. Chi GSTs exhibit a high glutathionylation activity towards isothiocyanates, compounds that are normally found in plants. Here, the crystallization of two GSTs are presented: TeGST produced by Thermosynechococcus elongates BP-1 and SeGST from Synechococcus elongates PCC 6301. Both enzymes formed crystals that diffracted to high resolution and appeared to be suitable for further X-ray diffraction studies. The structures of these GSTs may shed further light on the evolution of GST catalytic activity and in particular why these enzymes possess catalytic activity towards plant antimicrobial compounds. PMID:19407380

  12. Structural basis for the interaction of antibiotics with peptidyl transferase center in eubacteria

    SciTech Connect

    Schlunzen, Frank; Zarivach, Raz; Harms, Jörg; Bashan, Anat; Tocilj, Ante; Albrecht, Renate; Yonath, Ada; Franceschi, Francois

    2009-10-07

    Ribosomes, the site of protein synthesis, are a major target for natural and synthetic antibiotics. Detailed knowledge of antibiotic binding sites is central to understanding the mechanisms of drug action. Conversely, drugs are excellent tools for studying the ribosome function. To elucidate the structural basis of ribosome-antibiotic interactions, we determined the high-resolution X-ray structures of the 50S ribosomal subunit of the eubacterium Deinococcus radiodurans, complexed with the clinically relevant antibiotics chloramphenicol, clindamycin and the three macrolides erythromycin, clarithromycin and roxithromycin. We found that antibiotic binding sites are composed exclusively of segments of 23S ribosomal RNA at the peptidyl transferase cavity and do not involve any interaction of the drugs with ribosomal proteins. Here we report the details of antibiotic interactions with the components of their binding sites. Our results also show the importance of putative Mg{sup +2} ions for the binding of some drugs. This structural analysis should facilitate rational drug design.

  13. Crystallization and preliminary X-ray analysis of glutathione transferases from cyanobacteria

    SciTech Connect

    Feil, Susanne C.; Tang, Julian; Hansen, Guido; Gorman, Michael A.; Wiktelius, Eric; Stenberg, Gun; Parker, Michael W.

    2009-05-08

    Glutathione S-transferases (GSTs) are a group of multifunctional enzymes that are found in animals, plants and microorganisms. Their primary function is to remove toxins derived from exogenous sources or the products of metabolism from the cell. Mammalian GSTs have been extensively studied, in contrast to bacterial GSTs which have received relatively scant attention. A new class of GSTs called Chi has recently been identified in cyanobacteria. Chi GSTs exhibit a high glutathionylation activity towards isothiocyanates, compounds that are normally found in plants. Here, the crystallization of two GSTs are presented: TeGST produced by Thermosynechococcus elongates BP-1 and SeGST from Synechococcus elongates PCC 6301. Both enzymes formed crystals that diffracted to high resolution and appeared to be suitable for further X-ray diffraction studies. The structures of these GSTs may shed further light on the evolution of GST catalytic activity and in particular why these enzymes possess catalytic activity towards plant antimicrobial compounds.

  14. Supergenomic network compression and the discovery of EXP1 as a glutathione transferase inhibited by artesunate

    PubMed Central

    Lisewski, Andreas Martin; Quiros, Joel P.; Ng, Caroline L.; Adikesavan, Anbu Karani; Miura, Kazutoyo; Putluri, Nagireddy; Eastman, Richard T.; Scanfeld, Daniel; Regenbogen, Sam J.; Altenhofen, Lindsey; Llinás, Manuel; Sreekumar, Arun; Long, Carole; Fidock, David A.; Lichtarge, Olivier

    2014-01-01

    Summary A central problem in biology is to identify gene function. One approach is to infer function in large supergenomic networks of interactions and ancestral relationships among genes; however, their analysis can be computationally prohibitive. We show here that these biological networks are compressible. They can be shrunk dramatically by eliminating redundant evolutionary relationships and this process is efficient because in these networks the number of compressible elements rises linearly rather than exponentially as in other complex networks. Compression enables global network analysis to computationally harness hundreds of interconnected genomes and to produce functional predictions. As a demonstration, we show that the essential, but functionally uncharacterized Plasmodium falciparum antigen EXP1 is a membrane glutathione S-transferase. EXP1 efficiently degrades cytotoxic hematin, is potently inhibited by artesunate, and is associated with artesunate metabolism and susceptibility in drug-pressured malaria parasites. These data implicate EXP1 in the mode of action of a frontline antimalarial drug. PMID:25126794

  15. Biochemical properties of an omega-class glutathione S-transferase of the silkmoth, Bombyx mori.

    PubMed

    Yamamoto, Kohji; Nagaoka, Sumiharu; Banno, Yutaka; Aso, Yoichi

    2009-05-01

    A cDNA encoding an omega-class glutathione S-transferase of the silkmoth, Bombyx mori (bmGSTO), was cloned by reverse transcriptase-polymerase chain reaction. The resulting clone was sequenced and deduced for amino acid sequence, which revealed 40, 40, and 39% identities to omega-class GSTs from human, pig, and mouse, respectively. A recombinant protein (rbmGSTO) was functionally overexpressed in Escherichia coli cells in a soluble form and purified to homogeneity. rbmGSTO was able to catalyze the biotranslation of glutathione with 1-chloro-2,4-dinitrobenzene, a model substrate for GST, as well as with 4-hydroxynonenal, a product of lipid peroxidation. This enzyme was shown to have high affinity for organophosphorus insecticide and was present abundantly in silkmoth strain exhibiting fenitrothion resistance. These results indicate that bmGSTO could be involved in the increase in level of insecticide resistance for lepidopteran insects.

  16. Molybdenum and tungsten oxygen transferases--and functional diversity within a common active site motif.

    PubMed

    Pushie, M Jake; Cotelesage, Julien J; George, Graham N

    2014-01-01

    Molybdenum and tungsten are the only second and third-row transition elements with a known function in living organisms. The molybdenum and tungsten enzymes show common structural features, with the metal being bound by a pyranopterin-dithiolene cofactor called molybdopterin. They catalyze a variety of oxygen transferase reactions coupled with two-electron redox chemistry in which the metal cycles between the +6 and +4 oxidation states usually with water, either product or substrate, providing the oxygen. The functional roles filled by the molybdenum and tungsten enzymes are diverse; for example, they play essential roles in microbial respiration, in the uptake of nitrogen in green plants, and in human health. Together, the enzymes form a superfamily which is among the most prevalent known, being found in all kingdoms of life. This review discusses what is known of the active site structures and the mechanisms, together with some recent insights into the evolution of these important enzyme systems.

  17. Glutathione S-transferase mediates an ageing response to mitochondrial dysfunction

    PubMed Central

    Dancy, Beverley M.; Brockway, Nicole; Ramadasan-Nair, Renjini; Yang, Yoing; Sedensky, Margaret M.; Morgan, Philip G.

    2016-01-01

    To understand primary mitochondrial disease, we utilized a complex I-deficient Caenorhabditis elegans mutant, gas-1. These animals strongly upregulate the expression of gst-14 (encoding a glutathione S-transferase). Knockdown of gst-14 dramatically extends the lifespan of gas-1 and increases hydroxynonenal (HNE) modified mitochondrial proteins without improving complex I function. We observed no change in reactive oxygen species levels as measured by Mitosox staining, consistent with a potential role of GST-14 in HNE clearance. The upregulation of gst-14 in gas-1 animals is specific to the pharynx. These data suggest that an HNE-mediated response in the pharynx could be beneficial for lifespan extension in the context of complex I dysfunction in C. elegans. Thus, whereas HNE is typically considered damaging, our work is consistent with recent reports of its role in signaling, and that in this case, the signal is pro-longevity in a model of mitochondrial dysfunction. PMID:26704446

  18. Functional Identification of Proteus mirabilis eptC Gene Encoding a Core Lipopolysaccharide Phosphoethanolamine Transferase

    PubMed Central

    Aquilini, Eleonora; Merino, Susana; Knirel, Yuriy A.; Regué, Miguel; Tomás, Juan M.

    2014-01-01

    By comparison of the Proteus mirabilis HI4320 genome with known lipopolysaccharide (LPS) phosphoethanolamine transferases, three putative candidates (PMI3040, PMI3576, and PMI3104) were identified. One of them, eptC (PMI3104) was able to modify the LPS of two defined non-polar core LPS mutants of Klebsiella pneumoniae that we use as surrogate substrates. Mass spectrometry and nuclear magnetic resonance showed that eptC directs the incorporation of phosphoethanolamine to the O-6 of l-glycero-d-mano-heptose II. The eptC gene is found in all the P. mirabilis strains analyzed in this study. Putative eptC homologues were found for only two additional genera of the Enterobacteriaceae family, Photobacterium and Providencia. The data obtained in this work supports the role of the eptC (PMI3104) product in the transfer of PEtN to the O-6 of l,d-HepII in P. mirabilis strains. PMID:24756091

  19. Recombinant human dihydroxyacetonephosphate acyl-transferase characterization as an integral monotopic membrane protein.

    PubMed

    Piano, Valentina; Nenci, Simone; Magnani, Francesca; Aliverti, Alessandro; Mattevi, Andrea

    2016-12-02

    Although the precise functions of ether phospholipids are still poorly understood, significant alterations in their physiological levels are associated either to inherited disorders or to aggressive metastatic cancer. The essential precursor, alkyl-dihydroxyacetone phosphate (DHAP), for all ether phospholipids species is synthetized in two consecutive reactions performed by two enzymes sitting on the inner side of the peroxisomal membrane. Here, we report the characterization of the recombinant human DHAP acyl-transferase, which performs the first step in alkyl-DHAP synthesis. By exploring several expression systems and designing a number of constructs, we were able to purify the enzyme in its active form and we found that it is tightly bound to the membrane through the N-terminal residues. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  20. Activity of carboxylesterases, glutathione-S-transferase and monooxygenase on Rhipicephalus microplus exposed to fluazuron.

    PubMed

    Gaudêncio, Fabrício Nascimento; Klafke, Guilherme Marcondes; Tunholi-Alves, Vinícius Menezes; Ferreira, Thaís Paes; Coelho, Cristiane Nunes; da Fonseca, Adivaldo Henrique; da Costa Angelo, Isabele; Pinheiro, Jairo

    2017-10-01

    The objective of this study was to assess the effect of the exposure to fluazuron on the activity of common pesticide detoxification enzyme groups in the cattle tick (Rhipicephalus microplus). Engorged females of a susceptible strain (POA) and a resistant strain (Jaguar) were exposed in vitro to fluazuron and their eggs and larvae were used to compare the activities of the general esterases, mixed-function oxidases (MFO) and glutathione-S-transferase (GST). The results showed significant elevation in MFO contents and esterases activity in the resistant strain when compared with the susceptible strain, in eggs and larvae respectively. In the POA strain, the MFO activity in eggs was down-regulated by fluazuron exposure. Based on these results, it can be concluded that different detoxification enzymes can act in distinct pathways depending on the tick's development stage, and may be related to fluazuron detoxification in resistant strains. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Glutathione transferases are structural and functional outliers in the thioredoxin fold.

    PubMed

    Atkinson, Holly J; Babbitt, Patricia C

    2009-11-24

    Glutathione transferases (GSTs) are ubiquitous scavengers of toxic compounds that fall, structurally and functionally, within the thioredoxin fold suprafamily. The fundamental catalytic capability of GSTs is catalysis of the nucleophilic addition or substitution of glutathione at electrophilic centers in a wide range of small electrophilic compounds. While specific GSTs have been studied in detail, little else is known about the structural and functional relationships between different groupings of GSTs. Through a global analysis of sequence and structural similarity, it was determined that variation in the binding of glutathione between the two major subgroups of cytosolic (soluble) GSTs results in a different mode of glutathione activation. Additionally, the convergent features of glutathione binding between cytosolic GSTs and mitochondrial GST kappa are described. The identification of these structural and functional themes helps to illuminate some of the fundamental contributions of the thioredoxin fold to catalysis in the GSTs and clarify how the thioredoxin fold can be modified to enable new functions.

  2. Inhibition of the PCAF histone acetyl transferase and cell proliferation by isothiazolones.

    PubMed

    Dekker, Frank J; Ghizzoni, Massimo; van der Meer, Nanette; Wisastra, Rosalina; Haisma, Hidde J

    2009-01-15

    Small molecule HAT inhibitors are useful tools to unravel the role of histone acetyl transferases (HATs) in the cell and have relevance for oncology. We present a systematic investigation of the inhibition of the HAT p300/CBP Associated Factor (PCAF) by isothiazolones with different substitutions. 5-chloroisothiazolones proved to be the most potent inhibitors of PCAF. The growth inhibition of 4 different cell lines was studied and the growth of two cell lines (A2780 and HEK 293) was inhibited at micromolar concentrations by 5-chloroisothiazolones. Furthermore, the 5-chloroisothiazolone preservative Kathon CG that is used in cosmetics inhibited PCAF and the growth of cell lines A2780 and HEK 293, which indicates that this preservative should be applied with care.

  3. Glutathione-S-transferase-pi (GST-pi) expression in renal cell carcinoma

    PubMed Central

    Horti, Maria; Kandilaris, Kosmas; Skolarikos, Andreas; Trakas, Nikolaos; Kastriotis, Ioannis; Deliveliotis, Charalambos

    2015-01-01

    Multidrug resistance correlates with unfavourable treatment outcomes in numerous cancers including renal cell carcinoma. The expression and clinical relevance of Glutathione-S-transferase-pi (GST-pi), a multidrug resistance factor, in kidney tumors remain controversial. We analyzed the expression of GST-pi in 60 formalin-fixed, paraffin-embedded renal cell carcinoma samples by immunohistochemistry and compared them with matched normal regions of the kidney. A significantly higher expression of GST-pi was observed in 87% of clear cell carcinoma and 50% of papillary subtypes. GST-pi expression did not correlate with tumor grade or patient survival. GST-pi is unlikely to be a prognostic factor for renal cell carcinoma. However, further studies with large number of samples are warranted to establish the role of GST-pi, if any, in intrinsic or acquired resistance of renal cell carcinoma to conventional treatments.

  4. O-GlcNAc transferase invokes nucleotide sugar pyrophosphate participation in catalysis.

    PubMed

    Schimpl, Marianne; Zheng, Xiaowei; Borodkin, Vladimir S; Blair, David E; Ferenbach, Andrew T; Schüttelkopf, Alexander W; Navratilova, Iva; Aristotelous, Tonia; Albarbarawi, Osama; Robinson, David A; Macnaughtan, Megan A; van Aalten, Daan M F

    2012-12-01

    Protein O-GlcNAcylation is an essential post-translational modification on hundreds of intracellular proteins in metazoa, catalyzed by O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) using unknown mechanisms of transfer and substrate recognition. Through crystallographic snapshots and mechanism-inspired chemical probes, we define how human OGT recognizes the sugar donor and acceptor peptide and uses a new catalytic mechanism of glycosyl transfer, involving the sugar donor α-phosphate as the catalytic base as well as an essential lysine. This mechanism seems to be a unique evolutionary solution to the spatial constraints imposed by a bulky protein acceptor substrate and explains the unexpected specificity of a recently reported metabolic OGT inhibitor.

  5. Phi Class of Glutathione S-transferase Gene Superfamily Widely Exists in Nonplant Taxonomic Groups

    PubMed Central

    Munyampundu, Jean-Pierre; Xu, You-Ping; Cai, Xin-Zhong

    2016-01-01

    Glutathione S-transferases (GSTs) constitute a superfamily of enzymes involved in detoxification of noxious compounds and protection against oxidative damage. GST class Phi (GSTF), one of the important classes of plant GSTs, has long been considered as plant specific but was recently found in basidiomycete fungi. However, the range of nonplant taxonomic groups containing GSTFs remains unknown. In this study, the distribution and phylogenetic relationships of nonplant GSTFs were investigated. We identified GSTFs in ascomycete fungi, myxobacteria, and protists Naegleria gruberi and Aureococcus anophagefferens. GSTF occurrence in these bacteria and protists correlated with their genome sizes and habitats. While this link was missing across ascomycetes, the distribution and abundance of GSTFs among ascomycete genomes could be associated with their lifestyles to some extent. Sequence comparison, gene structure, and phylogenetic analyses indicated divergence among nonplant GSTFs, suggesting polyphyletic origins during evolution. Furthermore, in silico prediction of functional partners suggested functional diversification among nonplant GSTFs. PMID:26884677

  6. Purification and properties of 4-hydroxybutyrate coenzyme A transferase from Clostridium aminobutyricum.

    PubMed Central

    Scherf, U; Buckel, W

    1991-01-01

    A new coenzyme A (CoA)-transferase from the anaerobe Clostridium aminobutyricum catalyzing the formation of 4-hydroxybutyryl-CoA from 4-hydroxybutyrate and acetyl-CoA is described. The enzyme was purified to homogeneity by standard techniques, including fast protein liquid chromatography under aerobic conditions. Its molecular mass was determined to be 110 kDa, and that of the only subunit was determined to be 54 kDa, indicating a homodimeric structure. Besides acetate and acetyl-CoA, the following substrates were detected (in order of decreasing kcat/Km): 4-hydroxybutyryl-CoA, butyryl-CoA and propionyl-CoA, vinyl-acetyl-CoA (3-butenoyl-CoA), and 5-hydroxyvaleryl-CoA. In an indirect assay the corresponding acids were also found to be substrates; however, DL-lactate, DL-2-hydroxybutyrate, DL-3-hydroxybutyrate, crotonate, and various dicarboxylates were not. PMID:1768145

  7. Towards understanding oral health.

    PubMed

    Zaura, Egija; ten Cate, Jacob M

    2015-01-01

    During the last century, dental research has focused on unraveling the mechanisms behind various oral pathologies, while oral health was typically described as the mere absence of oral diseases. The term 'oral microbial homeostasis' is used to describe the capacity of the oral ecosystem to maintain microbial community stability in health. However, the oral ecosystem itself is not stable: throughout life an individual undergoes multiple physiological changes while progressing through infancy, childhood, adolescence, adulthood and old age. Recent discussions on the definition of general health have led to the proposal that health is the ability of the individual to adapt to physiological changes, a condition known as allostasis. In this paper the allostasis principle is applied to the oral ecosystem. The multidimensionality of the host factors contributing to allostasis in the oral cavity is illustrated with an example on changes occurring in puberty. The complex phenomenon of oral health and the processes that prevent the ecosystem from collapsing during allostatic changes in the entire body are far from being understood. As yet individual components (e.g. hard tissues, microbiome, saliva, host response) have been investigated, while only by consolidating these and assessing their multidimensional interactions should we be able to obtain a comprehensive understanding of the ecosystem, which in turn could serve to develop rational schemes to maintain health. Adapting such a 'system approach' comes with major practical challenges for the entire research field and will require vast resources and large-scale multidisciplinary collaborations.

  8. Oral microbiota and cancer

    PubMed Central

    Meurman, Jukka H.

    2010-01-01

    Inflammation caused by infections may be the most important preventable cause of cancer in general. However, in the oral cavity the role of microbiota in carcinogenesis is not known. Microbial populations on mouth mucosa differ between healthy and malignant sites and certain oral bacterial species have been linked with malignancies but the evidence is still weak in this respect. Nevertheless, oral microorganisms inevitably up-regulate cytokines and other inflammatory mediators that affect the complex metabolic pathways and may thus be involved in carcinogenesis. Poor oral health associates statistically with prevalence of many types of cancer, such as pancreatic and gastrointestinal cancer. Furthermore, several oral micro-organisms are capable of converting alcohol to carcinogenic acetaldehyde which also may partly explain the known association between heavy drinking, smoking, poor oral health and the prevalence of oral and upper gastrointestinal cancer. A different problem is the cancer treatment-caused alterations in oral microbiota which may lead to the emergence of potential pathogens and subsequent other systemic health problems to the patients. Hence clinical guidelines and recommendations have been presented to control oral microbiota in patients with malignant disease, but also in this area the scientific evidence is weak. More controlled studies are needed for further conclusion. PMID:21523227

  9. Bimaxillary Oral Focal Mucinosis.

    PubMed

    Yadav, Sunil; Malik, Sunita; Mittal, Hitesh Chander; Singh, Gurdarshan; Kamra, Hemlata

    2016-10-01

    Oral focal mucinosis is considered as oral counterpart of cutaneous focal mucinosis. The preoperative diagnosis of mucinosis is almost impossible because of its rarity and clinical similarity to other lesions of various etiologies. The histological diagnosis of oral mucinosis is important to better understand the etiopathogenesis, treatment modalities, and any recurrence of the lesion besides differentiating from the other soft tissue lesions.The purpose of this paper is to report the first case of bimaxillary involvement with dome-shaped elevated, rounded, asymptomatic, normally colored swelling in left posterior palatal mucosa and left mandibular posterior region in a 25-year old woman who was diagnosed as oral focal mucinosis histopathologically.

  10. Glutathione mediated regulation of oligomeric structure and functional activity of Plasmodium falciparum glutathione S-transferase.

    PubMed

    Tripathi, Timir; Rahlfs, Stefan; Becker, Katja; Bhakuni, Vinod

    2007-10-17

    In contrast to many other organisms, the malarial parasite Plasmodium falciparum possesses only one typical glutathione S-transferase. This enzyme, PfGST, cannot be assigned to any of the known GST classes and represents a most interesting target for antimalarial drug development. The PfGST under native conditions forms non-covalently linked higher aggregates with major population (approximately 98%) being tetramer. However, in the presence of 2 mM GSH, a dimer of PfGST is observed. Recently reported study on binding and catalytic properties of PfGST indicated a GSH dependent low-high affinity transition with simultaneous binding of two GSH molecules to PfGST dimer suggesting that GSH binds to low affinity inactive enzyme dimer converting it to high affinity functionally active dimer. In order to understand the role of GSH in tetramer-dimer transition of PfGST as well as in modulation of functional activity of the enzyme, detailed structural, functional and stability studies on recombinant PfGST in the presence and absence of GSH were carried out. Our data indicate that the dimer - and not the tetramer - is the active form of PfGST, and that substrate saturation is directly paralleled by dissociation of the tetramer. Furthermore, this dissociation is a reversible process indicating that the tetramer-dimer equilibrium of PfGST is defined by the surrounding GSH concentration. Equilibrium denaturation studies show that the PfGST tetramer has significantly higher stability compared to the dimer. The enhanced stability of the tetramer is likely to be due to stronger ionic interactions existing in it. This is the first report for any GST where an alteration in oligomeric structure and not just small conformational change is observed upon GSH binding to the enzyme. Furthermore we also demonstrate a reversible mechanism of regulation of functional activity of Plasmodium falciparum glutathione S-transferase via GSH induced dissociation of functionally inactive tetramer into

  11. Transferase activity function and system development process are critical in cattle embryo development.

    PubMed

    Adams, Heather A; Southey, Bruce R; Everts, Robin E; Marjani, Sadie L; Tian, Cindy X; Lewin, Harris A; Rodriguez-Zas, Sandra L

    2011-03-01

    Microarray gene expression experiments often consider specific developmental stages, tissue sources, or reproductive technologies. This focus hinders the understanding of the cattle embryo transcriptome. To address this, four microarray experiments encompassing three developmental stages (7, 25, 280 days), two tissue sources (embryonic or extra-embryonic), and two reproductive technologies (artificial insemination or AI and somatic cell nuclear transfer or NT) were combined using two sets of meta-analyses. The first set of meta-analyses uncovered 434 genes differentially expressed between AI and NT (regardless of stage or source) that were not detected by the individual-experiment analyses. The molecular function of transferase activity was enriched among these genes that included ECE2, SLC22A1, and a gene similar to CAMK2D. Gene POLG2 was over-expressed in AI versus NT 7-day embryos and was under-expressed in AI versus NT 25-day embryos. Gene HAND2 was over-expressed in AI versus NT extra-embryonic samples at 280 days yet under-expressed in AI versus NT embryonic samples at 7 days. The second set of meta-analyses uncovered enrichment of system, organ, and anatomical structure development among the genes differentially expressed between 7- and 25-day embryos from either reproductive technology. Genes PRDX1and SLC16A1 were over-expressed in 7- versus 25-day AI embryos and under-expressed in 7- versus 25-day NT embryos. Changes in stage were associated with high number of differentially expressed genes, followed by technology and source. Genes with transferase activity may hold a clue to the differences in efficiency between reproductive technologies.

  12. The Drosophila protein palmitoylome: Characterizing palmitoyl-thioesterases and DHHC palmitoyl-transferases

    PubMed Central

    Bannan, Barbra A.; Van Etten, Jamie; Kohler, John A.; Tsoi, Yui; Hansen, Nicole M.; Sigmon, Stacey; Fowler, Elizabeth; Buff, Haley; Williams, Tiffany S.; Ault, Jeffrey G.; Glaser, Robert L.; Korey, Christopher A.

    2010-01-01

    Palmitoylation is the post-translational addition of a palmitate moiety to a cysteine residue through a covalent thioester bond. The addition and removal of this modification is controlled by both palmitoyl acyl-transferases and thioesterases. Using bioinformatic analysis, we identified 22 DHHC family palmitoyl acyl-transferase homologs in the Drosophila genome. We used in situ hybridization, RT-PCR, and published FlyAtlas microarray data to characterize the expression patterns of all 22 fly homologs. Our results indicate that all are expressed genes, but several, including CG1407, CG4676, CG5620, CG6017/dHIP14, CG6618, CG6627, and CG17257 appear to be enriched in neural tissues suggesting that they are important for neural function. Furthermore, we have found that several may be expressed in a sex-specific manner with adult male-specific expression of CG4483 and CG17195. Using tagged versions of the DHHC genes, we demonstrate that fly DHHC proteins are primarily located in either the Golgi Apparatus or Endoplasmic Reticulum in S2 cells, except for CG1407, which was found on the plasma membrane. We also characterized the subcellular localization and expression of the three known thioesterases: Palmitoyl-protein Thioesterase 1 (Ppt1), Palmitoyl-protein Thioesterase 2 (Ppt2), and Acyl-protein Thioesterase 1 (APT1). Our results indicate that Ppt1 and Ppt2 are the major lysosomal thioesterases while APT1 is the likely cytoplasmic thioesterase. Finally, in vivo rescue experiments show that Ppt2 expression cannot rescue the neural inclusion phenotypes associated with loss of Ppt1, further supporting distinct functions and substrates for these two thioesterases. These results will serve as the basis for a more complete understanding of the protein palmitoylome's normal cellular functions in the fly and will lead to further insights into the molecular etiology of diseases associated with the mis-regulation of palmitoylation. PMID:18719403

  13. Global Deletion of Glutathione S-Transferase A4 Exacerbates Developmental Nonalcoholic Steatohepatitis.

    PubMed

    Ronis, Martin; Mercer, Kelly; Engi, Bridgette; Pulliam, Casey; Zimniak, Piotr; Hennings, Leah; Shearn, Colin; Badger, Thomas; Petersen, Dennis

    2017-02-01

    We established a mouse model of developmental nonalcoholic steatohepatitis (NASH) by feeding a high polyunsaturated fat liquid diet to female glutathione-S-transferase 4-4 (Gsta4(-/-))/peroxisome proliferator activated receptor α (Ppara(-/-)) double knockout 129/SvJ mice for 12 weeks from weaning. We used it to probe the importance of lipid peroxidation in progression of NASH beyond simple steatosis. Feeding Gsta4(-/-)/Ppara(-/-) double-knockout (dKO) mice liquid diets containing corn oil resulted in a percentage fat-dependent increase in steatosis and necroinflammatory injury (P < 0.05). Increasing fat to 70% from 35% resulted in increases in formation of 4-hydroxynonenal protein adducts accompanied by evidence of stellate cell activation, matrix remodeling, and fibrosis (P < 0.05). Comparison of dKO mice with wild-type (Wt) and single knockout mice revealed additive effects of Gsta4(-/-) and Ppara(-/-) silencing on steatosis, 4-hydroxynonenal adduct formation, oxidative stress, serum alanine amino transferase, expression of tumor necrosis factor alpha, Il6, interferon mRNA, and liver pathology (P < 0.05). Induction of Cyp2e1 protein by high-fat diet was suppressed in Gsta4(-/-) and dKO groups (P < 0.05). The dKO mice had similar levels of markers of stellate cell activation and matrix remodeling as Ppara(-/-) single KO mice. These data suggest that lipid peroxidation products play a role in progression of liver injury to steatohepatitis in NASH produced by high-fat feeding during development but appear less important in development of fibrosis. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

  14. A Glutathione Transferase from Agrobacterium tumefaciens Reveals a Novel Class of Bacterial GST Superfamily

    PubMed Central

    Skopelitou, Katholiki; Dhavala, Prathusha; Papageorgiou, Anastassios C.; Labrou, Nikolaos E.

    2012-01-01

    In the present work, we report a novel class of glutathione transferases (GSTs) originated from the pathogenic soil bacterium Agrobacterium tumefaciens C58, with structural and catalytic properties not observed previously in prokaryotic and eukaryotic GST isoenzymes. A GST-like sequence from A. tumefaciens C58 (Atu3701) with low similarity to other characterized GST family of enzymes was identified. Phylogenetic analysis showed that it belongs to a distinct GST class not previously described and restricted only in soil bacteria, called the Eta class (H). This enzyme (designated as AtuGSTH1-1) was cloned and expressed in E. coli and its structural and catalytic properties were investigated. Functional analysis showed that AtuGSTH1-1 exhibits significant transferase activity against the common substrates aryl halides, as well as very high peroxidase activity towards organic hydroperoxides. The crystal structure of AtuGSTH1-1 was determined at 1.4 Å resolution in complex with S-(p-nitrobenzyl)-glutathione (Nb-GSH). Although AtuGSTH1-1 adopts the canonical GST fold, sequence and structural characteristics distinct from previously characterized GSTs were identified. The absence of the classic catalytic essential residues (Tyr, Ser, Cys) distinguishes AtuGSTH1-1 from all other cytosolic GSTs of known structure and function. Site-directed mutagenesis showed that instead of the classic catalytic residues, an Arg residue (Arg34), an electron-sharing network, and a bridge of a network of water molecules may form the basis of the catalytic mechanism. Comparative sequence analysis, structural information, and site-directed mutagenesis in combination with kinetic analysis showed that Phe22, Ser25, and Arg187 are additional important residues for the enzyme's catalytic efficiency and specificity. PMID:22496785

  15. Structural studies of a baboon (Papio sp.) plasma protein inhibitor of cholesteryl ester transferase.

    PubMed

    Buchko, G W; Rozek, A; Kanda, P; Kennedy, M A; Cushley, R J

    2000-08-01

    A 38-residue protein associated with cholesteryl ester transfer inhibition has been identified in baboons (Papio sp.). The cholesteryl ester transfer inhibitor protein (CETIP) corresponds to the N-terminus of baboon apoC-I. Relative to CETIP, baboon apoC-I is a weak inhibitor of baboon cholesteryl ester transferase (CET). To study the structural features responsible for CET inhibition, CETIP was synthesized by solid-phase methods. Using sodium dodecyl sulfate (SDS) to model the lipoprotein environment, the solution structure of CETIP was probed by optical and 1H NMR spectroscopy. Circular dichroism data show that the protein lacks a well-defined structure in water but, upon the addition of SDS, becomes helical (56%). A small blue shift of 8 nm was observed in the intrinsic tryptophan fluorescence of CETIP in the presence of saturating amounts of SDS, suggesting that tryptophan-23 is not buried deeply in the lipid environment. The helical nature of CETIP in the presence of SDS was confirmed by upfield 1Halpha secondary shifts and an average solution structure determined by distance geometry/simulated annealing calculations using 476 NOE-based distance restraints. The backbone (N-Calpha-C=O) root-mean-square deviation of an ensemble of 17 out of 25 calculated structures superimposed on the average structure was 1.06+0.30 A using residues V4-P35 and 0.51+/-0.17 A using residues A7-S32. Although the side-chain orientations fit the basic description of a class A amphipathic helix, both intramolecular salt bridge formation and "snorkeling" of basic side chains toward the polar face play minor, if any, roles in stabilizing the lipid-bound amphipathic structure. Conformational features of the calculated structures for CETIP are discussed relative to models of CETIP inhibition of cholesteryl ester transferase.

  16. Mitochondrial carnitine palmitoyl transferase-II inactivity aggravates lipid accumulation in rat hepatocarcinogenesis

    PubMed Central

    Gu, Juan-Juan; Yao, Min; Yang, Jie; Cai, Yin; Zheng, Wen-Jie; Wang, Li; Yao, Deng-Bing; Yao, Deng-Fu

    2017-01-01

    AIM To investigate the dynamic alteration of mitochondrial carnitine palmitoyl transferase II (CPT-II) expression during malignant transformation of rat hepatocytes. METHODS Sprague-Dawley male rats were fed with normal, high fat (HF), and HF containing 2-fluorenylacetamide (2-FAA) diet, respectively. According to the Hematoxylin and Eosin staining of livers, rats were divided into control, fatty liver, degeneration, precancerous, and cancerous groups. Liver lipids were dyed with Oil Red O, CPT-II alterations were analyzed by immunohistochemistry, and compared with CPT-II specific concentration (μg/mg protein). Levels of total cholesterol (Tch), triglyceride (TG), and amino-transferases [alanine aminotransferase (ALT), aspartate aminotransferase (AST)] were determined by the routine methods. RESULTS After intake of HF and/or HF+2-FAA diets, the rat livers showed mass lipid accumulation. The lipid level in the control group was significantly lower than that in other groups. The changes of serum TG and Tch levels were abnormally increasing, 2-3 times more than those in the controls (P < 0.05). During the rat liver morphological changes from normal to cancer development process with hepatocyte injury, serum AST and ALT levels were significantly higher (4-8 times, P < 0.05) than those in the control group. The specific concentration of CPT-II in liver tissues progressively decreased during hepatocyte malignant transformation, with the lowest CPT-II levels in the cancer group than in any of the other groups (P < 0.05). CONCLUSION Low CPT-II expression might lead to abnormal hepatic lipid accumulation, which should promote the malignant transformation of hepatocytes. PMID:28127199

  17. Mechanistic studies of inactivation of glutathione S-transferase Pi isozyme by a haloenol lactone derivative.

    PubMed

    Zheng, Jiang; Liu, Guangxian; Tozkoparan, Birsen; Wen, Dingyi

    2005-03-01

    Cancer chemotherapy often fails due to acquired drug resistance. One of the most critical biochemical changes observed in drug-resistant tumor cells is over-expression of glutathione S-transferase Pi isozyme (GSTP1). Glutathione S-transferase inhibitors have been used as potentiating agents of chemotherapeutic drugs. Earlier we reported haloenol lactone 1 as a site-directed GSTP1 inactivator. We proposed that enzymatic hydrolysis of the haloenol lactone may be the initial step of GSTP1 chemical modification, resulting in the inactivation of the enzyme. Enzyme inactivation is initiated through addition of Cys-47 to the lactone ring, which is opened in the process to form an alpha-bromoketone adduct. The acidity of Cys-47 confers good leaving group properties, and rapid hydrolysis occurs to generate an alpha-bromoketoacid intermediate. The reaction may proceed via alkylation of the transient thioester to form a six-membered ring episulfonium ion intermediate which would be yet more reactive toward hydrolysis, with either process leading to the observed mass increase of 230 Da. To probe the importance of the bromine of the lactone in GST inactivation, we designed and synthesized compound 2. Unlike lactone 1, lactone 2 did not show time-dependent inhibitory effect on GSTP1. Incubation of compounds 1 and 2 with excess of N-acetyl cysteine produced the corresponding di-N-acetyl cysteine conjugate and mono-N-acetyl cysteine conjugate, respectively. To probe the role of Cys-47 in the inactivation of GSTP1 by compound 1, we prepared mutant C47A GSTP1. The mutant GSTP1 still showed good activity toward CDNB, but it lost susceptibility to the inactivation by compound 1. In addition, LC-MS/MS technique allowed us to identify the modified Cys-47 after the enzyme was exposed to compound 1.

  18. Molecular mimicry between cockroach and helminth glutathione S-transferases promotes cross-reactivity and cross-sensitization

    USDA-ARS?s Scientific Manuscript database

    The extensive similarities between helminth proteins and allergens are thought to contribute to helminth-driven allergic sensitization. We investigated the molecular and structural similarities between Bla g 5, a major glutathione-S transferase (GST) allergen of cockroaches, and the GST of Wucherer...

  19. Function and phylogeny of bacterial butyryl-CoA:acetate transferases and their diversity in the proximal colon of swine

    USDA-ARS?s Scientific Manuscript database

    Studying the host-associated butyrate-producing bacterial community is important because butyrate is essential for colonic homeostasis and gut health. Previous research has identified the butyryl-coA:acetate transferase (2.3.8.3) as a the main gene for butyrate production in intestinal ecosystems; h...

  20. Uncovering the enzymatic pKa of the ribosomal peptidyl transferase reaction utilizing a fluorinated puromycin derivative.

    PubMed

    Okuda, Kensuke; Seila, Amy C; Strobel, Scott A

    2005-05-03

    The ribosome-catalyzed peptidyl transferase reaction displays a complex pH profile resulting from two functional groups whose deprotonation is important for the reaction, one within the A-site substrate and a second unidentified group thought to reside in the rRNA peptidyl transferase center. Here we report the synthesis and activity of the beta,beta-difluorophenylalanyl derivative of puromycin, an A-site substrate. The fluorine atoms reduce the pK(a) of the nucleophilic alpha-amino group (<5.0) such that it is deprotonated at all pHs amenable to ribosomal analysis (pH 5.2-9.5). In the 50S modified fragment assay, this substrate reacts substantially faster than puromycin at neutral or acidic pH. The reaction follows a simplified pH profile that is dependent only upon deprotonation of a titratable group within the ribosomal active site. This feature will simplify characterization of the peptidyl transferase reaction mechanism. On the basis of the reaction efficiency of the doubly fluorinated substrate compared to the unfluorinated derivative, the Bronsted coefficient for the nucleophile is estimated to be substantially smaller than that reported for uncatalyzed aminolysis reactions, which has important mechanistic implications for the peptidyl transferase reaction.

  1. BIOTRANSFORMATION AND GENOTOXICITY OF THE DRINKING WATER DISINFECTION BYPRODUCT BROMODICHLOROMETHANE: DNA BINDING MEDIATED BY GLUTATHIONE TRANSFERASE THETA 1-1

    EPA Science Inventory

    The drinking water disinfection byproduct bromodichloromethane (CHBrCl2) was
    previously shown to be mutagenic in Salmonella typhimurium that overexpress rat glutathione
    transferase theta 1-1 (GSTT1-1). Several experimental approaches were undertaken in this study
    to inve...

  2. Characterization of spermidine hydroxycinnamoyl transferases from eggplant (Solanum melongena L.) and its wild relative Solanum richardii Dunal

    USDA-ARS?s Scientific Manuscript database

    Eggplant produces a variety of hydroxycinnamic acid amides (HCAAs) that play an important role in plant development and adaptation to environmental changes. However, the HCAA pathway remains largely uncharacterized in Solanaceae. In this study, a spermidine hydroxycinnamoyl transferase (SHT) from eg...

  3. Stereoselectivity of rat liver glutathione transferase isoenzymes for alpha-bromoisovaleric acid and alpha-bromoisovalerylurea enantiomers.

    PubMed Central

    Te Koppele, J M; Coles, B; Ketterer, B; Mulder, G J

    1988-01-01

    The stereoselectivity of purified rat GSH transferases towards alpha-bromoisovaleric acid (BI) and its amide derivative alpha-bromoisovalerylurea (BIU) was investigated. GSH transferase 2-2 was the only enzyme to catalyse the conjugation of BI and was selective for the (S)-enantiomer. The conjugation of (R)- and (S)-BIU was catalysed by the isoenzymes 2-2, 3-3 and 4-4. Transferase 1-1 was less active, and no catalytic activity was observed with transferase 7-7. Isoenzymes 1-1 and 2-2 of the Alpha multigene family preferentially catalysed the conjugation of the (S)-enantiomer of BIU (and BI), whereas isoenzymes 3-3 and 4-4 of the Mu multigene family preferred (R)-BIU. The opposite stereoselectivity of conjugation of BI and BIU previously observed in isolated rat hepatocytes and the summation of activities of enzymes known to be present in hepatocytes on the basis of present data are in accord. PMID:3421896

  4. The glutathione-S-transferase Mu 1 null genotype modulates ozone-induced airway inflammation in humans*

    EPA Science Inventory

    Background: The Glutathione-S-Transferase Mu 1 null genotype has been reported to be a risk factor for acute respiratory disease associated with increases in ambient air ozone. Ozone is known to cause an immediate decrease in lung function and increased airway inflammation. Howev...

  5. The glutathione-S-transferase Mu 1 null genotype modulates ozone-induced airway inflammation in humans*

    EPA Science Inventory

    Background: The Glutathione-S-Transferase Mu 1 null genotype has been reported to be a risk factor for acute respiratory disease associated with increases in ambient air ozone. Ozone is known to cause an immediate decrease in lung function and increased airway inflammation. Howev...

  6. COMPARATIVE EXPRESSION OF TWO ALPHA CLASS GLUTATHIONE S-TRANSFERASES IN HUMAN ADULT AND PRENATAL LIVER TISSUES. (R827441)

    EPA Science Inventory

    Abstract

    The ability of the fetus to detoxify transplacental drugs and chemicals can be a critical determinant of teratogenesis and developmental toxicity. Developmentally regulated expression of alpha class glutathione S-transferases (GSTs) is of particular int...

  7. The pleuromutilin drugs tiamulin and valnemulin bind to the RNA at the peptidyl transferase centre on the ribosome.

    PubMed

    Poulsen, S M; Karlsson, M; Johansson, L B; Vester, B

    2001-09-01

    The pleuromutilin antibiotic derivatives, tiamulin and valnemulin, inhibit protein synthesis by binding to the 50S ribosomal subunit of bacteria. The action and binding site of tiamulin and valnemulin was further characterized on Escherichia coli ribosomes. It was revealed that these drugs are strong inhibitors of peptidyl transferase and interact with domain V of 23S RNA, giving clear chemical footprints at nucleotides A2058-9, U2506 and U2584-5. Most of these nucleotides are highly conserved phylogenetically and functionally important, and all of them are at or near the peptidyl transferase centre and have been associated with binding of several antibiotics. Competitive footprinting shows that tiamulin and valnemulin can bind concurrently with the macrolide erythromycin but compete with the macrolide carbomycin, which is a peptidyl transferase inhibitor. We infer from these and previous results that tiamulin and valnemulin interact with the rRNA in the peptidyl transferase slot on the ribosomes in which they prevent the correct positioning of the CCA-ends of tRNAs for peptide transfer.

  8. The structure of the neisserial lipooligosaccharide phosphoethanolamine transferase A (LptA) required for resistance to polymyxin.

    PubMed

    Wanty, Christopher; Anandan, Anandhi; Piek, Susannah; Walshe, James; Ganguly, Jhuma; Carlson, Russell W; Stubbs, Keith A; Kahler, Charlene M; Vrielink, Alice

    2013-09-23

    Gram-negative bacteria possess an outer membrane envelope consisting of an outer leaflet of lipopolysaccharides, also called endotoxins, which protect the pathogen from antimicrobial peptides and have multifaceted roles in virulence. Lipopolysaccharide consists of a glycan moiety attached to lipid A, embedded in the outer membrane. Modification of the lipid A headgroups by phosphoethanolamine (PEA) or 4-amino-arabinose residues increases resistance to the cationic cyclic polypeptide antibiotic, polymyxin. Lipid A PEA transferases are members of the YhjW/YjdB/YijP superfamily and usually consist of a transmembrane domain anchoring the enzyme to the periplasmic face of the cytoplasmic membrane attached to a soluble catalytic domain. The crystal structure of the soluble domain of the protein of the lipid A PEA transferase from Neisseria meningitidis has been determined crystallographically and refined to 1.4Å resolution. The structure reveals a core hydrolase fold similar to that of alkaline phosphatase. Loop regions in the structure differ, presumably to enable interaction with the membrane-localized substrates and to provide substrate specificity. A phosphorylated form of the putative nucleophile, Thr280, is observed. Metal ions present in the active site are coordinated to Thr280 and to residues conserved among the family of transferases. The structure reveals the protein components needed for the transferase chemistry; however, substrate-binding regions are not evident and are likely to reside in the transmembrane domain of the protein. © 2013 Elsevier Ltd. All rights reserved.

  9. Dimethyl adenosine transferase (KsgA) deficiency in Salmonella Enteritidis confers susceptibility to high osmolarity and virulence attenuation in chickens

    USDA-ARS?s Scientific Manuscript database

    : Dimethyladenosine transferase (KsgA) performs diverse roles in bacteria including ribosomal maturation, DNA mismatch repair, and synthesis of KsgA is responsive to antibiotics and cold temperature. We previously showed that ksgA mutation in Salmonella Enteritidis results in impaired invasiveness i...

  10. BIOTRANSFORMATION AND GENOTOXICITY OF THE DRINKING WATER DISINFECTION BYPRODUCT BROMODICHLOROMETHANE: DNA BINDING MEDIATED BY GLUTATHIONE TRANSFERASE THETA 1-1

    EPA Science Inventory

    The drinking water disinfection byproduct bromodichloromethane (CHBrCl2) was
    previously shown to be mutagenic in Salmonella typhimurium that overexpress rat glutathione
    transferase theta 1-1 (GSTT1-1). Several experimental approaches were undertaken in this study
    to inve...

  11. Polymerase θ is a robust terminal transferase that oscillates between three different mechanisms during end-joining

    PubMed Central

    Kent, Tatiana; Mateos-Gomez, Pedro A; Sfeir, Agnel; Pomerantz, Richard T

    2016-01-01

    DNA polymerase θ (Polθ) promotes insertion mutations during alternative end-joining (alt-EJ) by an unknown mechanism. Here, we discover that mammalian Polθ transfers nucleotides to the 3’ terminus of DNA during alt-EJ in vitro and in vivo by oscillating between three different modes of terminal transferase activity: non-templated extension, templated extension in cis, and templated extension in trans. This switching mechanism requires manganese as a co-factor for Polθ template-independent activity and allows for random combinations of templated and non-templated nucleotide insertions. We further find that Polθ terminal transferase activity is most efficient on DNA containing 3’ overhangs, is facilitated by an insertion loop and conserved residues that hold the 3’ primer terminus, and is surprisingly more proficient than terminal deoxynucleotidyl transferase. In summary, this report identifies an unprecedented switching mechanism used by Polθ to generate genetic diversity during alt-EJ and characterizes Polθ as among the most proficient terminal transferases known. DOI: http://dx.doi.org/10.7554/eLife.13740.001 PMID:27311885

  12. Transmutation of human glutathione transferase A2-2 with peroxidase activity into an efficient steroid isomerase.

    PubMed

    Pettersson, Par L; Johansson, Ann-Sofie; Mannervik, Bengt

    2002-08-16

    A major goal in protein engineering is the tailor-making of enzymes for specified chemical reactions. Successful attempts have frequently been based on directed molecular evolution involving libraries of random mutants in which variants with desired properties were identified. For the engineering of enzymes with novel functions, it would be of great value if the necessary changes of the active site could be predicted and implemented. Such attempts based on the comparison of similar structures with different substrate selectivities have previously met with limited success. However, the present work shows that the knowledge-based redesign restricted to substrate-binding residues in human glutathione transferase A2-2 can introduce high steroid double-bond isomerase activity into the enzyme originally characterized by glutathione peroxidase activity. Both the catalytic center activity (k(cat)) and catalytic efficiency (k(cat)/K(m)) match the values of the naturally evolved glutathione transferase A3-3, the most active steroid isomerase known in human tissues. The substrate selectivity of the mutated glutathione transferase was changed 7000-fold by five point mutations. This example demonstrates the functional plasticity of the glutathione transferase scaffold as well as the potential of rational active-site directed mutagenesis as a complement to DNA shuffling and other stochastic methods for the redesign of proteins with novel functions.

  13. COMPARATIVE EXPRESSION OF TWO ALPHA CLASS GLUTATHIONE S-TRANSFERASES IN HUMAN ADULT AND PRENATAL LIVER TISSUES. (R827441)

    EPA Science Inventory

    Abstract

    The ability of the fetus to detoxify transplacental drugs and chemicals can be a critical determinant of teratogenesis and developmental toxicity. Developmentally regulated expression of alpha class glutathione S-transferases (GSTs) is of particular int...

  14. Biotinylation of histones by human serum biotinidase: assessment of biotinyl-transferase activity in sera from normal individuals and children with biotinidase deficiency.

    PubMed

    Hymes, J; Fleischhauer, K; Wolf, B

    1995-10-01

    Serum biotinidase has biotinyl-transferase activity in addition to biocytin hydrolase activity. A sensitive assay for biotinyl-transferase activity was developed based on the transfer of biotin from biocytin to histones. Biotinidase biotinyl-transferase occurs at physiological and alkaline pHs, whereas hydrolysis of biocytin occurs optimally at pH 4.5 to 6.0. Measurement of hydrolysis requires micromolar concentrations of biocytin, whereas biotinylation of histones can be detected readily at 1.5 nM biocytin. Because polylysine is readily biotinylated by biotinidase in the presence of biocytin, whereas polyarginine is not, the enzyme likely transfers biotin to the epsilon-amino group of lysyl residues. To determine if patients who are deficient in biocytin hydrolase activity are also deficient in biotinyl-transferase activity, serum from 103 children (25 identified by exhibiting clinical symptoms and 78 detected by newborn screening) with profound biotinidase deficiency (less than 10% of mean normal biotinyl-p-aminobenzoate hydrolyzing activity) were assessed for biotinyl-transferase activity and for the presence of cross-reacting material (CRM) to antibodies prepared against purified serum biotinidase. Sera from all symptomatic patients, both CRM-negative and CRM-positive, had no biotinyl-transferase activity. Sera that was CRM-negative from children ascertained by newborn screening also had no biotinyl-transferase activity, whereas sera from 67% of the CRM-positive children identified by newborn screening had varying degrees of biotinyl-transferase activity. These results indicate that there is a large group of enzyme-deficient children detected by newborn screening who are different biochemically from those who are symptomatic. The clinical relevance of having some degree of biotinyl-transferase activity for individuals with biotinidase deficiency remains to be determined. In addition, it is important to determine if biotinyl-transferase activity, especially

  15. Dexmedetomidine Oral Mucosa Patch for Sedation Suppresses Apoptosis in Hippocampus of Normal Rats

    PubMed Central

    2017-01-01

    Purpose Dexmedetomidine, an α2-adrenergic agonist, provides sedative and analgesic effects without significant respiratory depression. Dexmedetomidine has been suggested to have an antiapoptotic effect in response to various brain insults. We developed an oral mucosa patch using dexmedetomidine for sedation. The effects of the dexmedetomidine oral mucosa patch on cell proliferation and apoptosis in the hippocampus were evaluated. Methods A hydrogel oral mucosa patch was adhered onto the oral cavity of physiologically normal rats, and was attached for 2 hours, 6 hours, 12 hours, or 24 hours. Plasma dexmedetomidine concentrations were determined by liquid chromatography– electrospray ionization–tandem mass spectrometry–multiple-ion reaction monitoring (LC-ESI-MS/MS-MRM). Cell proliferation in the hippocampus was detected by Ki-67 immunohistochemistry. Caspase-3 immunohistochemistry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining, and Western blotting for Bax and Bcl-2 were performed to detect hippocampal apoptosis. The levels of brain-derived neurotrophic factor (BDNF) and tyrosine kinase B (TrkB) in the hippocampus were also measured by Western blotting. Results Plasma dexmedetomidine concentration increased according to the attachment time of the dexmedetomidine oral mucosa patch. Hippocampal cell proliferation did not change due to the dexmedetomidine oral mucosa patch, and the dexmedetomidine oral mucosa patch exerted no significant effect on BDNF or TrkB expression. In contrast, the dexmedetomidine oral mucosa patch exerted an antiapoptotic effect depending on the attachment time of the dexmedetomidine oral mucosa patch. Conclusions A dexmedetomidine oral mucosa patch can be used as a convenient tool for sedation, and is of therapeutic value due to its antiapoptotic effects under normal conditions. PMID:28446017

  16. An alternative mechanism for the catalysis of peptide bond formation by L/F transferase: substrate binding and orientation.

    PubMed

    Fung, Angela W; Ebhardt, H Alexander; Abeysundara, Heshani; Moore, Jack; Xu, Zhizhong; Fahlman, Richard P

    2011-06-17

    Eubacterial leucyl/phenylalanyl tRNA protein transferase (L/F transferase) catalyzes the transfer of a leucine or a phenylalanine from an aminoacyl-tRNA to the N-terminus of a protein substrate. This N-terminal addition of an amino acid is analogous to that of peptide synthesis by ribosomes. A previously proposed catalytic mechanism for Escherichia coli L/F transferase identified the conserved aspartate 186 (D186) and glutamine 188 (Q188) as key catalytic residues. We have reassessed the role of D186 and Q188 by investigating the enzymatic reactions and kinetics of enzymes possessing mutations to these active-site residues. Additionally three other amino acids proposed to be involved in aminoacyl-tRNA substrate binding are investigated for comparison. By quantitatively measuring product formation using a quantitative matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-based assay, our results clearly demonstrate that, despite significant reduction in enzymatic activity as a result of different point mutations introduced into the active site of L/F transferase, the formation of product is still observed upon extended incubations. Our kinetic data and existing X-ray crystal structures result in a proposal that the critical roles of D186 and Q188, like the other amino acids in the active site, are for substrate binding and orientation and do not directly participate in the chemistry of peptide bond formation. Overall, we propose that L/F transferase does not directly participate in the chemistry of peptide bond formation but catalyzes the reaction by binding and orientating the substrates for reaction in an analogous mechanism that has been described for ribosomes.

  17. Inhibition of the ribosomal peptidyl transferase reaction by the mycarose moiety of the antibiotics carbomycin, spiramycin and tylosin.

    PubMed

    Poulsen, S M; Kofoed, C; Vester, B

    2000-12-01

    Many antibiotics, including the macrolides, inhibit protein synthesis by binding to ribosomes. Only some of the macrolides affect the peptidyl transferase reaction. The 16-member ring macrolide antibiotics carbomycin, spiramycin, and tylosin inhibit peptidyl transferase. All these have a disaccharide at position 5 in the lactone ring with a mycarose moiety. We have investigated the functional role of this mycarose moiety. The 14-member ring macrolide erythromycin and the 16-member ring macrolides desmycosin and chalcomycin do not inhibit the peptidyl transferase reaction. These drugs have a monosaccharide at position 5 in the lactone ring. The presence of mycarose was correlated with inhibition of peptidyl transferase, footprints on 23 S rRNA and whether the macrolide can compete with binding of hygromycin A to the ribosome. The binding sites of the macrolides to Escherichia coli ribosomes were investigated by chemical probing of domains II and V of 23 S rRNA. The common binding site is around position A2058, while effects on U2506 depend on the presence of the mycarose sugar. Also, protection at position A752 indicates that a mycinose moiety at position 14 in 16-member ring macrolides interact with hairpin 35 in domain II. Competitive footprinting of ribosomal binding of hygromycin A and macrolides showed that tylosin and spiramycin reduce the hygromycin A protections of nucleotides in 23 S rRNA and that carbomycin abolishes its binding. In contrast, the macrolides that do not inhibit the peptidyl transferase reaction bind to the ribosomes concurrently with hygromycin A. Data are presented to argue that a disaccharide at position 5 in the lactone ring of macrolides is essential for inhibition of peptide bond formation and that the mycarose moiety is placed near the conserved U2506 in the central loop region of domain V 23 S rRNA.

  18. Epilepsy and oral care.

    PubMed

    Fiske, Janice; Boyle, Carole

    2002-05-01

    Epilepsy is a common symptom of an underlying neurological disorder. The seizures can take a variety of forms. Both the condition and its medical management can affect oral health. Prevention of oral disease and carefully planned dental treatment are essential to the well-being of people with epilepsy.

  19. Migraine and oral contraceptives.

    PubMed

    Mousa, G Y

    1982-10-01

    Migraine is a common complaint in optometric practice. Three cases of migrainous patients taking oral contraceptives are presented in this report. The role of oral contraceptives in triggering a migraine attack and possibly elevating the risk of a stroke in a patient with migraine is discussed. The counseling an optometrist can provide in such cases in discussed.

  20. Oral environment and cancer.

    PubMed

    Kudo, Yasusei; Tada, Hidesuke; Fujiwara, Natsumi; Tada, Yoshiko; Tsunematsu, Takaaki; Miyake, Yoichiro; Ishimaru, Naozumi

    2016-01-01

    Cancer is now the leading cause of death in Japan. A rapid increase in cancer mortality is expected as Japan is facing a super-aged society. Many causes of cancer are known to be closely linked to life style factors, such as smoking, drinking, and diet. The oral environment is known to be involved in the pathogenesis and development of various diseases such as bronchitis, pneumonia, diabetes, heart disease, and dementia. Because the oral cavity acts as the bodily entrance for air and food, it is constantly exposed to foreign substances, including bacteria and viruses. A large number of bacteria are endemic to the oral cavity, and indigenous oral flora act to prevent the settlement of foreign bacteria. The oral environment is influenced by local factors, including dental plaque, tartar, teeth alignment, occlusion, an incompatible prosthesis, and bad lifestyle habits, and systemic factors, including smoking, consumption of alcohol, irregular lifestyle and eating habits, obesity, stress, hormones, and heredity. It has recently been revealed that the oral environment is associated with cancer. In particular, commensal bacteria in the oral cavity are involved in the development of cancer. Moreover, Candida, human papilloma virus and Epstein-Barr virus as well as commensal bacteria have been reported to be associated with the pathogenesis of cancer. In this review, we introduce recent findings of the correlation between the oral environment and cancer.

  1. Oral contraceptives in migraine.

    PubMed

    Allais, Gianni; Gabellari, Ilaria Castagnoli; De Lorenzo, Cristina; Mana, Ornella; Benedetto, Chiara

    2009-03-01

    Combined oral contraceptives are a safe and highly effective method of birth control, but they can also raise problems of clinical tolerability and/or safety in migraine patients. It is now commonly accepted that, in migraine with aura, the use of combined oral contraceptives is always contraindicated, and that their intake must also be suspended by patients suffering from migraine without aura if aura symptoms appear. The newest combined oral contraceptive formulations are generally well tolerated in migraine without aura, and the majority of migraine without aura sufferers do not show any problems with their use; nevertheless, the last International Classification of Headache Disorders identifies at least two entities evidently related to the use of combined oral contraceptives: exogenous hormone-induced headache and estrogen-withdrawal headache. As regards the safety, even if both migraine and combined oral contraceptive intake are associated with an increased risk of ischemic stroke, migraine without aura per se is not a contraindication for combined oral contraceptive use. Other risk factors (tobacco use, hypertension, hyperlipidemia, obesity and diabetes) must be carefully considered when prescribing combined oral contraceptives in migraine without aura patients, in particular in women aged over 35 years. Furthermore, the exclusion of a hereditary thrombophilia and of alterations of coagulative parameters should precede any decision of combined oral contraceptive prescription in migraine patients.

  2. Oral Transliterating. PEPNet Tipsheet

    ERIC Educational Resources Information Center

    Troiano, Claire A.

    2010-01-01

    An oral transliterator provides communication access to a person who is deaf or hard of hearing and who uses speechreading and speaking as a means of communicating. The oral transliterator, positioned in front of the speechreader, inaudibly repeats the spoken message, making it as speechreadable as possible. This is called Expressive Oral…

  3. ORAL AMELANOTIC MELANOMA

    PubMed Central

    Adisa, A.O.; Olawole, W.O.; Sigbeku, O.F.

    2012-01-01

    Malignant melanomas of the mucosal regions of the head and neck are extremely rare neoplasms accounting for less than 1% of all melanomas. Approximately half of all head and neck melanomas occur in the oral cavity. Less than 2% of all melanomas lack pigmentation, in the oral mucosa however, up to 75% of cases are amelanotic. No etiologic factors or risk factors have been recognized for oral melanomas. Some authors have suggested that oral habits and selfmedication may be of etiological significance. Oral melanoma is rare but it is relatively frequent in countries like Japan, Uganda, and India. It is rarely identified under the age of 20 years. In Australia where cutaneous melanomas are relatively common primary melanoma of the oral mucosa is rare. The surface architecture of oral melanomas ranges from macular to ulcerated and nodular. The lesion is said to be asymptomatic in the early stages but may become ulcerated and painful in advanced lesions. The diagnosis of amelanotic melanoma is more difficult than that of pigmented lesions. The neoplasm consists of spindle-shaped cells with many mitotic figures and no cytoplasmic melanin pigmentation. Immunohistochemistry using S-100, HMB-45, Melan-A and MART-1 will help in establishing the correct diagnosis. Radical surgery with ample margins and adjuvant chemotherapy are appropriate management protocol for malignant melanoma. Oral melanoma is associated with poor prognosis but its amelanotic variant has even worse prognosis because it exhibits a more aggressive biology and because of difficulty in diagnosis which leads to delayed treatment. PMID:25161399

  4. Oral surgery. Basic techniques.

    PubMed

    Ross, D L; Goldstein, G S

    1986-09-01

    Some of the clinical problems most frequently seen in veterinary dentistry and their surgical solutions are discussed. Extraction of teeth, surgical repositioning of teeth, tooth transplant, oral abscesses of tooth origin, impaction of teeth, repair of maxillary canine oronasal fistula, and simple techniques for oral wiring are among the issues considered.

  5. Genomics of oral bacteria.

    PubMed

    Duncan, Margaret J

    2003-01-01

    Advances in bacterial genetics came with the discovery of the genetic code, followed by the development of recombinant DNA technologies. Now the field is undergoing a new revolution because of investigators' ability to sequence and assemble complete bacterial genomes. Over 200 genome projects have been completed or are in progress, and the oral microbiology research community has benefited through projects for oral bacteria and their non-oral-pathogen relatives. This review describes features of several oral bacterial genomes, and emphasizes the themes of species relationships, comparative genomics, and lateral gene transfer. Genomics is having a broad impact on basic research in microbial pathogenesis, and will lead to new approaches in clinical research and therapeutics. The oral microbiota is a unique community especially suited for new challenges to sequence the metagenomes of microbial consortia, and the genomes of uncultivable bacteria.

  6. Oral contraceptives: current status.

    PubMed

    Burkman, R T

    2001-03-01

    During the past four decades, oral contraceptives have remained a safe and effective method of birth control. Reductions in the estrogen and progestin dosages have significantly decreased the incidence of cardiovascular complications. The association between oral contraceptives and breast cancer appears to be primarily because of detection bias or possibly a promotional effect. Despite the changes in formulation, the problems related to side effects have not been totally solved. Because compliance and successful use is strongly affected by side effects, improvement in this area is probably the biggest challenge faced by developers of oral contraceptives. It is also clear that there are a growing number of significant noncontraceptive benefits that accrue in oral contraceptive users. Unfortunately, many women do not know about these benefits. Thus, one of the issues that providers need to continue to address is how to provide better information about oral contraceptives and contraception in general to patients.

  7. [Oral fluid bacteriocidal activity in complex diagnostics of oral disbiosis].

    PubMed

    Rabinovich, O F; Abramova, E S

    2012-01-01

    The possibility of examination of oral fluid bacteriocidal activity in complex diagnostics of oral mucosa disbiosis was evaluated. Thirty-seven patients were included in complex clinical and laboratory studies. The patients were divided in two groups: main group (30 patients exhibiting various grades of oral mucosa disbiosis) and control group (7 patients with no signs of oral disbiosis). The oral fluid bacteriocidal activity was examined by means of laser flow cytometry. Study results proved oral fluid bacteriocidal activity increase to correlate with the grade of oral mucosa disbiosis thus confirming the usefulness of the method in complex diagnostics of oral disbiosis.

  8. Oral Contraceptive Pill and PCOS

    MedlinePlus

    ... Health Gynecology Medical Conditions Nutrition & Fitness Emotional Health PCOS: The Oral Contraceptive Pill Posted under Health Guides . ... of oral contraceptive pills for young women with PCOS? Regular and Lighter Periods: Oral contraceptive pills can ...

  9. Literatura Oral Hispanica (Hispanic Oral Literature).

    ERIC Educational Resources Information Center

    McAlpine, Dave

    As part of a class in Hispanic Oral Literature, students collected pieces of folklore from various Hispanic residents in the region known as "Siouxland" in Iowa. Consisting of some of the folklore recorded from the residents, this paper includes 18 "cuentos y leyendas" (tales and legends), 48 "refranes" (proverbs), 17…

  10. Modelling and bioinformatics studies of the human Kappa-class glutathione transferase predict a novel third glutathione transferase family with similarity to prokaryotic 2-hydroxychromene-2-carboxylate isomerases.

    PubMed Central

    Robinson, Anna; Huttley, Gavin A; Booth, Hilary S; Board, Philip G

    2004-01-01

    The Kappa class of GSTs (glutathione transferases) comprises soluble enzymes originally isolated from the mitochondrial matrix of rats. We have characterized a Kappa class cDNA from human breast. The cDNA is derived from a single gene comprising eight exons and seven introns located on chromosome 7q34-35. Recombinant hGSTK1-1 was expressed in Escherichia coli as a homodimer (subunit molecular mass approximately 25.5 kDa). Significant glutathione-conjugating activity was found only with the model substrate CDNB (1-chloro-2,4-ditnitrobenzene). Hyperbolic kinetics were obtained for GSH (parameters: K(m)app, 3.3+/-0.95 mM; V(max)app, 21.4+/-1.8 micromol/min per mg of enzyme), while sigmoidal kinetics were obtained for CDNB (parameters: S0.5app, 1.5+/-1.0 mM; V(max)app, 40.3+/-0.3 micromol/min per mg of enzyme; Hill coefficient, 1.3), reflecting low affinities for both substrates. Sequence analyses, homology modelling and secondary structure predictions show that hGSTK1 has (a) most similarity to bacterial HCCA (2-hydroxychromene-2-carboxylate) isomerases and (b) a predicted C-terminal domain structure that is almost identical to that of bacterial disulphide-bond-forming DsbA oxidoreductase (root mean square deviation 0.5-0.6 A). The structures of hGSTK1 and HCCA isomerase are predicted to possess a thioredoxin fold with a polyhelical domain (alpha(x)) embedded between the beta-strands (betaalphabetaalpha(x)betabetaalpha, where the underlined elements represent the N and C motifs of the thioredoxin fold), as occurs in the bacterial disulphide-bond-forming oxidoreductases. This is in contrast with the cytosolic GSTs, where the helical domain occurs exclusively at the C-terminus (betaalphabetaalphabetabetaalphaalpha(x)). Although hGSTK1-1 catalyses some typical GST reactions, we propose that it is structurally distinct from other classes of cytosolic GSTs. The present study suggests that the Kappa class may have arisen in prokaryotes well before the divergence of the

  11. Developmental aspects of a unique glutathione S-transferase subunit Yx in the liver cytosol from rats with hereditary hyperbilirubinuria. Comparison with rat fetal liver transferase subunit Yfetus.

    PubMed Central

    Igarashi, T; Tsuchiya, T; Shikata, Y; Sagami, F; Tagaya, O; Horie, T; Satoh, T

    1992-01-01

    The unique glutathione S-transferase (GST) subunit Yx, which is undetectable in normal adult rat liver cytosol, was shown to occur in the liver cytosol of rats with hereditary hyperbilirubinuria (EHB). The Yx subunit is a member of the Alpha-class GST subunits, and is immunologically closely related to the Yc subunit. The Yx subunit has an apparent M(r) of 26,400, different from those of Ya (M(r) 25,800), Yb1 and Yb2 (both M(r) 27,200) and Yc (M(r) 28,400). During postnatal development in livers of EHB rats, the Yx subunit concentration in either sex was highest during the first week post partum and declined rapidly with age. Although the concentration of subunit Yx at 8 weeks of age accounted for about 60% in females and 40% in males of that observed in 1-week-old 'neonatal' male EHB rats, concentrations in females thereafter increased gradually to almost the neonatal level and remained at this high level at least up to 37 weeks of age, whereas the concentration in males did not increase again. Thus the post-pubertal Yx subunit concentration was 2-fold higher in females than in males. In contrast, in normal Sprague-Dawley rat liver, the Yfetus subunit, with the same M(r) as the Yx subunit, had the highest concentration in 10-day-old animals, declined rapidly thereafter, and was not detectable in the post-pubertal period. The Yfetus subunit was also immunoreactive with an antibody against GST YcYc. The analysis of GST subunits by reverse-phase h.p.l.c. revealed that the Yx subunit was eluted at a retention time different from other known subunits, but coincided with that of Yfetus. The N-terminal amino acid sequence of the Yx subunit displayed a high degree of sequence similarity to that of the Yfetus subunit. These data suggest that the Yx subunit in EHB rats may be very similar to, if not identical with, the Yfetus subunit. Images Fig. 1. Fig. 2. Fig. 3. PMID:1567376

  12. Atrazine Resistance in a Velvetleaf (Abutilon theophrasti) Biotype Due to Enhanced Glutathione S-Transferase Activity 1

    PubMed Central

    Anderson, Michael P.; Gronwald, John W.

    1991-01-01

    We previously reported that a velvetleaf (Abutilon theophrasti Medic) biotype found in Maryland was resistant to atrazine because of an enhanced capacity to detoxify the herbicide via glutathione conjugation (JW Gronwald, Andersen RN, Yee C [1989] Pestic Biochem Physiol 34: 149-163). The biochemical basis for the enhanced atrazine conjugation capacity in this biotype was examined. Glutathione levels and glutathione S-transferase activity were determined in extracts from the atrazine-resistant biotype and an atrazine-susceptible or “wild-type” velvetleaf biotype. In both biotypes, the highest concentration of glutathione (approximately 500 nanomoles per gram fresh weight) was found in leaf tissue. However, no significant differences were found in glutathione levels in roots, stems, or leaves of either biotype. In both biotypes, the highest concentration of glutathione S-transferase activity measured with 1-chloro-2,4-dinitrobenzene or atrazine as substrate was in leaf tissue. Glutathione S-transferase measured with 1-chloro-2,4-dinitrobenzene as substrate was 40 and 25% greater in leaf and stem tissue, respectively, of the susceptible biotype compared to the resistant biotype. In contrast, glutathione S-transferase activity measured with atrazine as substrate was 4.4- and 3.6-fold greater in leaf and stem tissue, respectively, of the resistant biotype. Kinetic analyses of glutathione S-transferase activity in leaf extracts from the resistant and susceptible biotypes were performed with the substrates glutathione, 1-chloro-2,4-dinitrobenzene, and atrazine. There was little or no change in apparent Km values for glutathione, atrazine, or 1-chloro-2,4-dinitrobenzene. However, the Vmax for glutathione and atrazine were approximately 3-fold higher in the resistant biotype than in the susceptible biotype. In contrast, the Vmax for 1-chloro-2,4-dinitrobenzene was 30% lower in the resistant biotype. Leaf glutathione S-transferase isozymes that exhibit activity with

  13. Biosynthesis of the Macrocyclic Diterpene Casbene in Castor Bean (Ricinus communis L.) Seedlings 1

    PubMed Central

    Dudley, Mark W.; Green, Terrence R.; West, Charles A.

    1986-01-01

    Farnesyl transferase (farnesyl pyrophosphate: isopentenyl pyrophosphate farnesyl transferase; geranylgeranyl pyrophosphate synthetase) was purified at least 400-fold from extracts of castor bean (Ricinus communis L.) seedlings that were elicited by exposure for 10 h to Rhizopus stolonifer spores. The purified enzyme was free of isopentenyl pyrophosphate isomerase and phosphatase activities which interfere with prenyl transferase assays. The purified enzyme showed a broad optimum for farnesyl transfer between pH 8 and 9. The molecular weight of the enzyme was estimated to be 72,000 ± 3,000 from its behavior on a calibrated G-100 Sephadex molecular sieving column. Mg2+ ion at 4 millimolar gave the greatest stimulation of activity; Mn2+ ion gave a small stimulation at 0.5 millimolar, but was inhibitory at higher concentrations. Farnesyl pyrophosphate (Km = 0.5 micromolar) in combination with isopentenyl pyrophosphate (Km = 3.5 micromolar) was the most effective substrate for the production of geranylgeranyl pyrophosphate. Geranyl pyrophosphate (Km = 24 micromolar) could replace farnesyl pyrophosphate as the allylic pyrophosphate substrate, but dimethylallyl pyrophosphate was not utilized by the enzyme. One peak of farnesyl transferase activity (geranylgeranyl pyrophosphate synthetase) and two peaks of geranyl transferase activity (farnesyl pyrophosphate synthetases) from extracts of whole elicited seedlings were resolved by DEAE A-25 Sephadex sievorptive ion exchange chromatography. These results suggest that the pathway for geranylgeranyl pyrophosphate synthesis in elicited castor bean seedlings involves the successive actions of two enzymes—a geranyl transferase which utilizes dimethylallypyrophosphate and isopentenyl pyrophosphate as substrates and a farnesyl transferase which utilizes the farnesyl pyrophosphate produced in the first step and isopentenyl pyrophosphate as substrates. PMID:16664818

  14. Examining the association between oral health and oral HPV infection.

    PubMed

    Bui, Thanh Cong; Markham, Christine M; Ross, Michael Wallis; Mullen, Patricia Dolan

    2013-09-01

    Oral human papillomavirus (HPV) infection is the cause of 40% to 80% of oropharyngeal cancers; yet, no published study has examined the role of oral health in oral HPV infection, either independently or in conjunction with other risk factors. This study examined the relation between oral health and oral HPV infection and the interactive effects of oral health, smoking, and oral sex on oral HPV infection. Our analyses comprised 3,439 participants ages 30 to 69 years for whom data on oral HPV and oral health were available from the nationally representative 2009-2010 National Health and Nutrition Examination Survey. Results showed that higher unadjusted prevalence of oral HPV infection was associated with four measures of oral health, including self-rated oral health as poor-to-fair [prevalence ratio (PR) = 1.56; 95% confidence interval (CI), 1.25-1.95], indicated the possibility of gum disease (PR = 1.51; 95% CI, 1.13-2.01), reported use of mouthwash to treat dental problems in the past week (PR = 1.28; 95% CI, 1.07-1.52), and higher number of teeth lost (Ptrend = 0.035). In multivariable logistic regression models, oral HPV infection had a statistically significant association with self-rated overall oral health (OR = 1.55; 95% CI, 1.15-2.09), independent of smoking and oral sex. In conclusion, poor oral health was an independent risk factor of oral HPV infection, irrespective of smoking and oral sex practices. Public health interventions may aim to promote oral hygiene and oral health as an additional measure to prevent HPV-related oral cancers.

  15. Oral availability of bilastine.

    PubMed

    Sádaba, B; Gómez-Guiu, A; Azanza, J R; Ortega, I; Valiente, R

    2013-05-01

    Bilastine (Bilaxten™) is a novel non-sedating H1 receptor antagonist (antihistamine) developed in the dosage form of oral tablets and indicated for the treatment of allergic rhinitis (seasonal and perennial) and urticaria. Several clinical trials have been performed in order to determine the efficacy and safety of bilastine. The aim of this trial was to study the absolute oral bioavailability of bilastine in humans. Twelve male and female adults were recruited into a single centre for a randomized, single-dose, open-label, controlled two-arm crossover study with a minimum 14-day washout period between the two single doses. Two single doses of bilastine were administered: a 20-mg oral tablet and a 10-mg intravenous formulation. Blood and urine samples were collected between 0 and 72 h post each administration. The clinical trial was carried out under quality assurance and quality control systems with standard operating procedures to ensure that the study was conducted and data generated in compliance with the protocol, Good Clinical Practice standards, International Conference on Harmonisation and other applicable regulations. Oral bioavailability of bilastine was 60.67 % with a 90 % parametric confidence interval of 53.79-67.56. The maximum bilastine concentration was measured 1.31 h after oral administration. Pharmacokinetic parameters were similar to those observed in previous studies. Tolerance to treatment was good, with no adverse events related to study medication. The absorption of bilastine after oral administration to healthy subjects was rapid. The absolute oral bioavailability was moderate.

  16. Personality and oral health.

    PubMed

    Thomson, W Murray; Caspi, Avshalom; Poulton, Richie; Moffitt, Terrie E; Broadbent, Jonathan M

    2011-10-01

    We investigated age-26 personality characteristics and age-32 oral health in a prospective study of a complete birth cohort born in Dunedin, New Zealand. Personality was measured using the Multidimensional Personality Questionnaire (MPQ). Oral health was measured using the short-form Oral Health Impact Profile (OHIP-14), a global measure, and dental examinations. Personality profiles were constructed for 916 individuals (50.8% men) using standardized MPQ scores, and multivariate analyses examined their association with oral health. Those reporting 1+ OHIP-14 impacts had higher Negative Emotionality scores (and lower Constraint and Positive Emotionality MPQ superfactor scores) than those who did not. After controlling for gender, clinical status, and the other two MPQ superfactors, those scoring higher on Negative Emotionality had a greater risk of reporting 1+ OHIP-14 impacts, as well as 3+ OHIP-14 impacts and worse-than-average oral health. They also had a greater risk of having lost at least one tooth from caries and of having 3+ decayed surfaces. Personality characteristics appear to shape self-reports of oral health. Personality is also a risk factor for clinical disease status, at least with respect to dental caries and its sequelae. Because the attitudes and values tapped into by personality tests can be altered by brief cognitive interventions, those might be useful in preventive dentistry. © 2011 Eur J Oral Sci.

  17. Oral health and nutrition.

    PubMed

    Pla, G W

    1994-03-01

    The relationships between oral health conditions, dietary practices and nutritional status, and general health status in the older American are complex, with many interrelating factors. Just as inadequate nutrition can affect oral health, poor oral health status affects food choices and, thus, nutritional status. It is clearly essential that the primary care practitioner and/or screening health professionals always include an evaluation of oral status in assessment of an elderly person. Effective care for the elderly dental patient requires knowledge about the disease of aging and the impact of those diseases on oral health and nutrition, pharmacology and drug interactions and their impact on oral health status, the biology of aging including sensory changes, the relationship of general medicine and systemic diseases, and psychology and sociology. The attitudes of empathy and understanding, caring and compassion, respect and a positive attitude toward the older patient, and flexibility in treatment planning are also critical elements. The interdisciplinary team of physicians, nurses, nutrition professionals, dentists, and social service professionals must all work together to ensure that good oral health status and adequate nutrition are maintained in older Americans. Recognizing and treating oral health and nutrition problems are important in improving the health and quality of life for the elderly population. Research that can provide more answers to health care problems in this growing group; educating professionals with respect to the relationships between oral health and nutrition; and public policy changes with regard to provision and funding of nutrition services, especially when provided by registered and/or licensed nutrition professionals, contribute to improving the health and quality of life for elders.

  18. Contribution of liver mitochondrial membrane-bound glutathione transferase to mitochondrial permeability transition pores

    SciTech Connect

    Hossain, Quazi Sohel; Ulziikhishig, Enkhbaatar; Lee, Kang Kwang; Yamamoto, Hideyuki; Aniya, Yoko

    2009-02-15

    We recently reported that the glutathione transferase in rat liver mitochondrial membranes (mtMGST1) is activated by S-glutathionylation and the activated mtMGST1 contributes to the mitochondrial permeability transition (MPT) pore and cytochrome c release from mitochondria [Lee, K.K., Shimoji, M., Quazi, S.H., Sunakawa, H., Aniya, Y., 2008. Novel function of glutathione transferase in rat liver mitochondrial membrane: role for cytochrome c release from mitochondria. Toxcol. Appl. Pharmacol. 232, 109-118]. In the present study we investigated the effect of reactive oxygen species (ROS), generator gallic acid (GA) and GST inhibitors on mtMGST1 and the MPT. When rat liver mitochondria were incubated with GA, mtMGST1 activity was increased to about 3 fold and the increase was inhibited with antioxidant enzymes and singlet oxygen quenchers including 1,4-diazabicyclo [2,2,2] octane (DABCO). GA-mediated mtMGST1 activation was prevented by GST inhibitors such as tannic acid, hematin, and cibacron blue and also by cyclosporin A (CsA). In addition, GA induced the mitochondrial swelling which was also inhibited by GST inhibitors, but not by MPT inhibitors CsA, ADP, and bongkrekic acid. GA also released cytochrome c from the mitochondria which was inhibited completely by DABCO, moderately by GST inhibitors, and somewhat by CsA. Ca{sup 2+}-mediated mitochondrial swelling and cytochrome c release were inhibited by MPT inhibitors but not by GST inhibitors. When the outer mitochondrial membrane was isolated after treatment of mitochondria with GA, mtMGST1 activity was markedly increased and oligomer/aggregate of mtMGST1 was observed. These results indicate that mtMGST1 in the outer mitochondrial membrane is activated by GA through thiol oxidation leading to protein oligomerization/aggregation, which may contribute to the formation of ROS-mediated, CsA-insensitive MPT pore, suggesting a novel mechanism for regulation of the MPT by mtMGST1.

  19. Inhibition of the recombinant cattle tick Rhipicephalus (Boophilus) annulatus glutathione S-transferase.

    PubMed

    Guneidy, Rasha A; Shahein, Yasser E; Abouelella, Amira M K; Zaki, Eman R; Hamed, Ragaa R

    2014-09-01

    Rhipicephalus (Boophilus) annulatus is a bloodsucking ectoparasite that causes severe production losses in the cattle industry. This study aims to evaluate the in vitro effects of tannic acid, hematin (GST inhibitors) and different plant extracts (rich in tannic acid) on the activity of the recombinant glutathione S-transferase enzyme of the Egyptian cattle tick R. annulatus (rRaGST), in order to confirm their ability to inhibit the parasitic essential detoxification enzyme glutathione S-transferase. Extraction with 70% ethanol of Hibiscus cannabinus (kenaf flowers), Punica granatum (red and white pomegranate peel), Musa acuminata (banana peel) (Musaceae), Medicago sativa (alfalfa seeds), Tamarindus indicus (seed) and Cuminum cyminum (cumin seed) were used to assess: (i) inhibitory capacities of rRaGST and (ii) their phenolic and flavonoid contents. Ethanol extraction of red pomegranate peel contained the highest content of phenolic compounds (29.95mg gallic acid/g dry tissue) compared to the other studied plant extracts. The highest inhibition activities of rRaGST were obtained with kenaf and red pomegranate peel (P. granatum) extracts with IC50 values of 0.123 and 0.136mg dry tissue/ml, respectively. Tannic acid was the more effective inhibitor of rRaGST with an IC50 value equal to 4.57μM compared to delphinidine-HCl (IC50=14.9±3.1μM). Gossypol had a weak inhibitory effect (IC50=43.7μM), and caffeic acid had almost no effect on tick GST activity. The IC50 values qualify ethacrynic acid as a potent inhibitor of rRaGST activity (IC50=0.034μM). Cibacron blue and hematin showed a considerable inhibition effect on rRaGST activity, and their IC50 values were 0.13μM and 7.5μM, respectively. The activity of rRaGST was highest for CDNB (30.2μmol/min/mg protein). The enzyme had also a peroxidatic activity (the specific activity equals 26.5μmol/min/mg protein). Both tannic acid and hematin inhibited rRaGST activity non-competitively with respect to GSH and

  20. Glutathione mediated regulation of oligomeric structure and functional activity of Plasmodium falciparum glutathione S-transferase

    PubMed Central

    Tripathi, Timir; Rahlfs, Stefan; Becker, Katja; Bhakuni, Vinod

    2007-01-01

    Background In contrast to many other organisms, the malarial parasite Plasmodium falciparum possesses only one typical glutathione S-transferase. This enzyme, PfGST, cannot be assigned to any of the known GST classes and represents a most interesting target for antimalarial drug development. The PfGST under native conditions forms non-covalently linked higher aggregates with major population (~98%) being tetramer. However, in the presence of 2 mM GSH, a dimer of PfGST is observed. Recently reported study on binding and catalytic properties of PfGST indicated a GSH dependent low-high affinity transition with simultaneous binding of two GSH molecules to PfGST dimer suggesting that GSH binds to low affinity inactive enzyme dimer converting it to high affinity functionally active dimer. In order to understand the role of GSH in tetramer-dimer transition of PfGST as well as in modulation of functional activity of the enzyme, detailed structural, functional and stability studies on recombinant PfGST in the presence and absence of GSH were carried out. Results Our data indicate that the dimer – and not the tetramer – is the active form of PfGST, and that substrate saturation is directly paralleled by dissociation of the tetramer. Furthermore, this dissociation is a reversible process indicating that the tetramer-dimer equilibrium of PfGST is defined by the surrounding GSH concentration. Equilibrium denaturation studies show that the PfGST tetramer has significantly higher stability compared to the dimer. The enhanced stability of the tetramer is likely to be due to stronger ionic interactions existing in it. Conclusion This is the first report for any GST where an alteration in oligomeric structure and not just small conformational change is observed upon GSH binding to the enzyme. Furthermore we also demonstrate a reversible mechanism of regulation of functional activity of Plasmodium falciparum glutathione S-transferase via GSH induced dissociation of functionally

  1. Activation and inhibition of rubber transferases by metal cofactors and pyrophosphate substrates.

    PubMed

    Scott, Deborah J; da Costa, Bernardo M T; Espy, Stephanie C; Keasling, Jay D; Cornish, Katrina

    2003-09-01

    Metal cofactors are necessary for the activity of alkylation by prenyl transfer in enzyme-catalyzed reactions. Rubber transferase (RuT, a cis-prenyl transferase) associated with purified rubber particles from Hevea brasiliensis, Parthenium argentatum and Ficus elastica can use magnesium and manganese interchangably to achieve maximum velocity. We define the concentration of activator required for maximum velocity as [A](max). The [A](max)(Mg2+) in F. elastica (100 mM) is 10 times the [A](max)(Mg2+) for either H. brasiliensis (10 mM) or P. argentatum (8 mM). The [A](max)(Mn2+) in F. elastica (11 mM), H. brasiliensis (3.8 mM) and P. argentatum (6.8 mM) and the [A](max)(Mg2+) in H. brasiliensis (10 mM) and P. argentatum (8 mM) are similar. The differences in [A](max)(Mg2+) correlate with the actual endogenous Mg(2+) concentrations in the latex of living plants. Extremely low Mn(2+) levels in vivo indicate that Mg(2+) is the RuT cofactor in living H. brasiliensis and F. elastica trees. Kinetic analyses demonstrate that FPP-Mg(2+) and FPP-Mn(2+) are active substrates for rubber molecule initiation, although free FPP and metal cations, Mg(2+) and Mn(2+), can interact independently at the active site with the following relative dissociation constants K(d)(FPP)

  2. O-GlcNAc Transferase Is Essential for Sensory Neuron Survival and Maintenance.

    PubMed

    Su, Cathy; Schwarz, Thomas L

    2017-02-22

    O-GlcNAc transferase (OGT) regulates a wide range of cellular processes through the addition of the O-GlcNAc sugar moiety to thousands of protein substrates. Because nutrient availability affects the activity of OGT, its role has been broadly studied in metabolic tissues. OGT is enriched in the nervous system, but little is known about its importance in basic neuronal processes in vivo Here, we show that OGT is essential for sensory neuron survival and maintenance in mice. Sensory neuron-specific knock-out of OGT results in behavioral hyposensitivity to thermal and mechanical stimuli accompanied by decreased epidermal innervation and cell-body loss in the dorsal root ganglia. These effects are observed early in postnatal development and progress as animals age. Cultured sensory neurons lacking OGT also exhibit decreased axonal outgrowth. The effects on neuronal health in vivo are not solely due to disruption of developmental processes, because inducing OGT knock-out in the sensory neurons of adult mice results in a similar decrease in nerve fiber endings and cell bodies. Significant nerve-ending loss occurs before a decrease in cell bodies; this phenotype is indicative of axonal dieback that progresses to neuronal death. Our findings demonstrate that OGT is important in regulating axonal maintenance in the periphery and the overall health and survival of sensory neurons.SIGNIFICANCE STATEMENT We show the importance of O-GlcNAc transferase (OGT) for sensory neuron health and survival in vivo This study is the first to find that loss of OGT results in neuronal cell death. Moreover, it suggests that aberrant O-GlcNAc signaling can contribute to the development of neuropathy. The sensory neurons lie outside of the blood-brain barrier and therefore, compared to central neurons, may have a greater need for mechanisms of metabolic sensing and compensation. Peripheral sensory neurons in particular are subject to degeneration in diabetes. Our findings provide a foundation

  3. Studies of the relationship between the catalytic activity and binding of non-substrate ligands by the glutathione S-transferases.

    PubMed Central

    Boyer, T D; Vessey, D A; Holcomb, C; Saley, N

    1984-01-01

    The dimeric enzyme glutathione S-transferase B is composed of two dissimilar subunits, referred to as Ya and Yc. Transferase B (YaYc) and two other transferases that are homodimers of the individual Ya and Yc subunits were purified from rat liver. Inhibition of these three enzymes by Indocyanine Green, biliverdin and several bile acids was investigated at different values of pH (range 6.0-8.0). Indocyanine Green, biliverdin and chenodeoxycholate were found to be effective inhibitors of transferases YaYc and YcYc at low (pH 6.0) but not high (pH 8.0) values of pH. Between these extremes of pH intermediate degrees of inhibition were observed. Cholate and taurochenodeoxycholate, however, were ineffective inhibitors of transferase YcYc at all values of pH. The observed differences in bile acids appeared to be due, in part, to differences in their state of ionization. In contrast with the above results, transferase YaYa was inhibited by at least 80% by the non-substrate ligands at all values of pH. These effects of pH on the three transferases could not be accounted for by pH-induced changes in the enzyme's affinity for the inhibitor. Thus those glutathione S-transferases that contain the Yc subunit are able to act simultaneously as both enzymes and binding proteins. In addition to enzyme structure, the state of ionization of the non-substrate ligands may also influence whether the transferases can perform both functions simultaneously. PMID:6696720

  4. Cloning and expression of clostridium acetobutylicum ATCC 824 acetoacetyl-coenzyme A:acetate/butyrate:coenzyme A-transferase in Escherichia coli

    SciTech Connect

    Cary, J.W.; Petersen, D.J.; Bennett, G.N. ); Papoutsakis, E.T. )

    1990-06-01

    Coenzyme A (CoA)-transferase (acetoacetyl-CoA:acetate/butyrate:CoA-transferase (butyrate-acetoacetate CoA-transferase) (EC 2.8.3.9)) of Clostridium acetobutylicum ATCC 824 is an important enzyme in the metabolic shift between the acid-producing and solvent-forming states of this organism. The genes encoding the two subunits of this enzyme have been cloned and subsequent subcloning experiments established the position of the structural genes for CoA-transferase. Complementation of Escherichia coli ato mutants with the recombinant plasmid pCoAT4 (pUC19 carrying a 1.8-kilobase insert of C. acetobutylicum DNA encoding CoA-transferase activity) enabled the transformants to grow on butyrate as a sole carbon source. Despite the ability of CoA-transferase to complement the ato defect in E. coli mutants, Southern blot and Western blot (immunoblot) analyses showed showed that neither the C. acetobutylicum genes encoding CoA-transferase nor the enzyme itself shared any apparent homology with its E. coli counterpart. Polypeptides of M{sub r} of the purified CoA-transferase subunits were observed by Western blot and maxicell analysis of whole-cell extracts of E.coli harboring pCoAT4. The proximity and orientation of the genes suggest that the genes encoding the two subunits of CoA-transferase may form an operon similar to that found in E. coli. In the plasmid, however, transcription appears to be primarily from the lac promoter of the vector.

  5. Structural snapshots along the reaction pathway of Yersinia pestis RipA, a putative butyryl-CoA transferase

    SciTech Connect

    Torres, Rodrigo; Lan, Benson; Latif, Yama; Chim, Nicholas; Goulding, Celia W.

    2014-04-01

    The crystal structures of Y. pestis RipA mutants were determined to provide insights into the CoA transferase reaction pathway. Yersinia pestis, the causative agent of bubonic plague, is able to survive in both extracellular and intracellular environments within the human host, although its intracellular survival within macrophages is poorly understood. A novel Y. pestis three-gene rip (required for intracellular proliferation) operon, and in particular ripA, has been shown to be essential for survival and replication in interferon γ-induced macrophages. RipA was previously characterized as a putative butyryl-CoA transferase proposed to yield butyrate, a known anti-inflammatory shown to lower macrophage-produced NO levels. RipA belongs to the family I CoA transferases, which share structural homology, a conserved catalytic glutamate which forms a covalent CoA-thioester intermediate and a flexible loop adjacent to the active site known as the G(V/I)G loop. Here, functional and structural analyses of several RipA mutants are presented in an effort to dissect the CoA transferase mechanism of RipA. In particular, E61V, M31G and F60M RipA mutants show increased butyryl-CoA transferase activities when compared with wild-type RipA. Furthermore, the X-ray crystal structures of E61V, M31G and F60M RipA mutants, when compared with the wild-type RipA structure, reveal important conformational changes orchestrated by a conserved acyl-group binding-pocket phenylalanine, Phe85, and the G(V/I)G loop. Binary structures of M31G RipA and F60M RipA with two distinct CoA substrate conformations are also presented. Taken together, these data provide CoA transferase reaction snapshots of an open apo RipA, a closed glutamyl-anhydride intermediate and an open CoA-thioester intermediate. Furthermore, biochemical analyses support essential roles for both the catalytic glutamate and the flexible G(V/I)G loop along the reaction pathway, although further research is required to fully

  6. [Schizophrenia and oral health].

    PubMed

    Moullan, M; Denis, F

    2017-04-01

    Mental health is an essential component of general health. Schizophrenia is a severe and chronic mental illness that affects higher brain functions. It is characterized by the presence of a mental dissociation, dampened or inappropriate affects, hallucinations and delirium. Schizophrenia has also a negative impact on oral health. As schizophrenia affects 1% of the population, every practitioner concerned with oral sphere will be confronted one day or another with a patient suffering from this disease. It is therefore important to acquire essential notions. The aim of our work was to make an update about factors that may affect oral health in patients with schizophrenia. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. Oral Lesions in Neonates

    PubMed Central

    Rao, Roopa S; Majumdar, Barnali; Jafer, Mohammed; Maralingannavar, Mahesh; Sukumaran, Anil

    2016-01-01

    ABSTRACT Oral lesions in neonates represent a wide range of diseases often creating apprehension and anxiety among parents. Early examination and prompt diagnosis can aid in prudent management and serve as baseline against the future course of the disease. The present review aims to enlist and describe the diagnostic features of commonly encountered oral lesions in neonates. How to cite this article: Patil S, Rao RS, Majumdar B, Jafer M, Maralingannavar M, Sukumaran A. Oral Lesions in Neonates. Int J Clin Pediatr Dent 2016;9(2):131-138. PMID:27365934

  8. Etiology of oral habits.

    PubMed

    Bayardo, R E; Mejia, J J; Orozco, S; Montoya, K

    1996-01-01

    The pedodontic admission histories of 1600 Mexican children were analyzed, to determine general epidemiologic factors or oral habits, as well as their relationship with identifiable biopsychosociologic factors. Fifty-six percent of the children gave evidence of an oral habit, with significant predisposition among female patients, single children, subjects in poor physical health (particularly from allergies), as well as children with histories of chronic health problems. Oral habits should be considered a major health hazard because of their high incidence. Successful treatment requires a multidisciplinary approach to the basic cause of the problem.

  9. Probiotics and Oral Health

    PubMed Central

    Haukioja, Anna

    2010-01-01

    The number of products containing probiotics, viable bacteria with proven health benefits, entering the market is increasing. Traditionally, probiotics have been associated with gut health, and most clinical interest has been focused on their use for prevention or treatment of gastrointestinal infections and diseases; however, during the last decade several investigators have also suggested the use of probiotics for oral health purposes. The aim of this review is to examine potential mechanisms of probiotic bacteria in the oral cavity and summarize observed effects of probiotics with respect to oral health. The review focuses on probiotic lactobacilli and bifidobacteria, genera that are most used in various probiotic products. PMID:20613927

  10. Does oral experience terminate ingestion?

    PubMed

    Swithers, S E; Hall, W G

    1994-10-01

    Using data from studies of ingestive behavior in developing rat pups we demonstrate how oral experience can contribute to the termination of ingestion. In rat pups, repeated oral stimulation with sweet solutions causes a decline in oral responsiveness. The diminished responsiveness is specific to the flavor of the stimulus experienced orally and can persist for several hours. We suggest that this experience-based decrement in responsiveness is best considered "oral habituation" and that oral habituation largely accounts for the onset of satiety. Post-ingestive feedback signals may have their influence through the oral habituation process or act in the context of oral habituation. Oral habituation is also shown to depend on the pattern of stimulus presentation, a phenomenon that adds considerable complexity to assessing the contributions of oral experience to satiety. The concept of oral habituation may be useful in understanding the immediate control of ingestion and the moment-to-moment expression of ingestive behavior in adult animals.

  11. 2-Phenethyl isothiocyanate, glutathione S-transferase M1 and T1 polymorphisms, and detoxification of volatile organic carcinogens and toxicants in tobacco smoke

    PubMed Central

    Yuan, Jian-Min; Murphy, Sharon E.; Stepanov, Irina; Wang, Renwei; Carmella, Steven G.; Nelson, Heather H.; Hatsukami, Dorothy; Hecht, Stephen S.

    2016-01-01

    Cigarette smoke contains relatively large quantities of volatile organic toxicants or carcinogens such as benzene, acrolein and crotonaldehyde. Among their detoxification products are mercapturic acids formed from glutathione conjugation, catalyzed in part by glutathione S-transferases (GST). A randomized phase 2 clinical trial with a crossover design was conducted to evaluate the effect of 2-phenethyl isothiocyanate (PEITC), a natural product formed from gluconasturtiin in certain cruciferous vegetables, on the detoxification of benzene, acrolein, and crotonaldehyde in 82 cigarette smokers. Urinary mercapturic acids of benzene, acrolein and crotonaldehyde at baseline and during treatment were quantified. Overall, oral PEITC supplementation increased the mercapturic acid formed from benzene by 24.6% (P=0.002) and acrolein by 15.1% (P=0.005), but had no effect on crotonaldehyde. A remarkably stronger effect was observed among subjects with the null genotype of both GSTM1 and GSTT1: in these individuals PEITC increased the detoxification metabolite of benzene by 95.4% (P<0.001), of acrolein by 32.7% (P=0.034), and of crotonaldehyde by 29.8% (P=0.006). In contrast, PEITC had no effect on these mercapturic acids in smokers possessing both genes. PEITC had no effect on the urinary oxidative stress biomarker 8-iso-prostaglandin F2α or the inflammation biomarker prostaglandin E2 metabolite. This trial demonstrates an important role of PEITC in detoxification of environmental carcinogens and toxicants which also occur in cigarette smoke. The selective effect of PEITC on detoxification in subjects lacking both GSTM1 and GSTT1 genes supports the epidemiological findings of stronger protection by dietary isothiocyanates against the development of lung cancer in such individuals. PMID:27099270

  12. 2-Phenethyl Isothiocyanate, Glutathione S-transferase M1 and T1 Polymorphisms, and Detoxification of Volatile Organic Carcinogens and Toxicants in Tobacco Smoke.

    PubMed

    Yuan, Jian-Min; Murphy, Sharon E; Stepanov, Irina; Wang, Renwei; Carmella, Steven G; Nelson, Heather H; Hatsukami, Dorothy; Hecht, Stephen S

    2016-07-01

    Cigarette smoke contains relatively large quantities of volatile organic toxicants or carcinogens such as benzene, acrolein, and crotonaldehyde. Among their detoxification products are mercapturic acids formed from glutathione conjugation, catalyzed in part by glutathione S-transferases (GST). A randomized phase II clinical trial with a crossover design was conducted to evaluate the effect of 2-phenethyl isothiocyanate (PEITC), a natural product formed from gluconasturtiin in certain cruciferous vegetables, on the detoxification of benzene, acrolein, and crotonaldehyde in 82 cigarette smokers. Urinary mercapturic acids of benzene, acrolein, and crotonaldehyde at baseline and during treatment were quantified. Overall, oral PEITC supplementation increased the mercapturic acid formed from benzene by 24.6% (P = 0.002) and acrolein by 15.1% (P = 0.005), but had no effect on crotonaldehyde. A remarkably stronger effect was observed among subjects with the null genotype of both GSTM1 and GSTT1: in these individuals, PEITC increased the detoxification metabolite of benzene by 95.4% (P < 0.001), of acrolein by 32.7% (P = 0.034), and of crotonaldehyde by 29.8% (P = 0.006). In contrast, PEITC had no effect on these mercapturic acids in smokers possessing both genes. PEITC had no effect on the urinary oxidative stress biomarker 8-iso-prostaglandin F2α or the inflammation biomarker prostaglandin E2 metabolite. This trial demonstrates an important role of PEITC in detoxification of environmental carcinogens and toxicants which also occur in cigarette smoke. The selective effect of PEITC on detoxification in subjects lacking both GSTM1 and GSTT1 genes supports the epidemiologic findings of stronger protection by dietary isothiocyanates against the development of lung cancer in such individuals. Cancer Prev Res; 9(7); 598-606. ©2016 AACR. ©2016 American Association for Cancer Research.

  13. Oral Hypersensitivity Reactions

    MedlinePlus

    ... of substances. The most common causes are food, food additives, drugs, oral hygiene products, and dental materials. Q: Are there any specific foods that are more commonly implicated in intraoral hypersensitivity ...

  14. Oral compound nevus.

    PubMed

    Cardoso, Lyzete Berriel; Consalaro, Alberto; da Silva Santos, Paulo Sérgio; da Silva Sampieri, Marcelo Bonifácio; Tinoco-Araújo, José Endrigo

    2014-02-18

    The melanocytic nevus is a benign and focal proliferation of nevus cells that can be congenital or acquired. Intraoral lesions are uncommon, and the etiology and pathogenesis are poorly understood. The occurrence rate of oral compound nevus is about 5.9% to 16.5% of all oral melanocytic nevi. A 22-year-old male patient presented with a dark brown macule on the buccal mucosa of the maxilla in the region of tooth 26. The lesion was elliptical, 0.7 x 0.5 cm, well circumscribed, asymptomatic, and the evolution time was unknown. An excisional biopsy was performed and microscopic analysis revealed nests of nevus cells in the epithelium and underlying connective tissue that were compatible with melanocytic compound nevus. Owing to the clinical similarity between oral melanocytic nevus and oral melanoma, a histopathological analysis is mandatory for definitive diagnosis.

  15. Massive Oral Decoding.

    ERIC Educational Resources Information Center

    Janicke, Eugene M.

    1981-01-01

    An intensive reading clinic used the Massive Oral Decoding (MOD) technique to help 10 reading disabled students (grades 7 and 8) increase independent reading skills. MOD stresses large amounts of reading practice at the student's independent level. (CL)

  16. Oral manifestations of menopause.

    PubMed

    Zachariasen, R D

    1993-12-01

    Menopause is a normal developmental stage in a woman's life, marking the permanent cessation of menstruation. It is the result of irreversible changes in the hormonal and reproductive functions of the ovaries. Menopause is accompanied by a number of characteristic physical changes; some of which occur in the oral cavity. The two most common oral manifestations of menopause are: oral discomfort, including pain, a burning sensation, dryness, and altered taste perception; and alveolar bone loss as a result of osteoporosis. Although menopause has been recognized for centuries, it has only been recently that the study of menopause has gained much attention. The purpose of this article is to review the basic physiology of menopause, and to present the etiology of the oral manifestations associated with menopause.

  17. Oral contraceptives and hypertension.

    PubMed

    Friedman, G D

    1977-01-01

    A variety of studies have noted that the use of oral contraceptives generally leads to mild increases in blood pressure which are usually reversible when the medication is discontinued. Representative data from the Walnut Creek Contraceptive Drug Study and the Royal College of General Practitioners Study concerning the magnitude of excess risk and relation to duration of use and pull content are shown. Preliminary data from women, aged 25-34 years, taking multiphasic health checkups in Oakland and San Francisco, suggest that black as well as white women are susceptible to this side effect of oral contraceptives. A method is given for estimating the proportion of hypertensives among a population of young women that is attributable to oral contraceptive use. Although the risk of pull-induced hypertension is small for the average user, oral contraceptives appear to be an important identifiable cause of hypertension in samples of women studied.

  18. Budesonide Oral Inhalation

    MedlinePlus

    Budesonide is used to prevent difficulty breathing, chest tightness, wheezing, and coughing caused by asthma. Budesonide powder for oral inhalation (Pulmicort Flexhaler) is used in adults and children 6 ...

  19. [Oral precancer and cancer].

    PubMed

    López-López, José; Omaña-Cepeda, Carlos; Jané-Salas, Enric

    2015-11-06

    We reviewed the concept of oral precancerous lesions, oral cancer, and the possibility of early diagnosis. With the keywords: premalignant oral lesions prevention, a search was performed over the past 10 years. Also clinical trials are searched from January 2011 until today with the keywords: oral cancer prevention AND dentistry. It is emphasized that there can be no significant changes related to the concept of precancerous lesions and cancer, and those relating to the early diagnosis. Despite the numerous described methods of screening, biopsy remains the most useful test, and therefore it is essential, mainly if we consider the new possibilities of molecular studies. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  20. Oral Cancer Foundation

    MedlinePlus

    ... to the disease drawn from literally hundreds of sources. Current Stories OCF Support Group A FREE and anonymous patient / survivor discussion forum is open to the public, where those currently fighting oral ...