The excision of radiation-induced lesions in DNA by a DNA repair enzyme complex, namely the UvrABC nuclease complex, has been investigated. Irradiated DNA was treated with the enzyme complex. DNA fractions were analyzed by gas chromatography/isotope-dilution mass spectrometry. The results showed that a number pyrimidine- and ...

One of the best-studied DNA repair pathways is nucleotide excision repair, a process consisting of DNA damage recognition, incision, excision, repair resynthesis, and DNA ligation. Escherichia coli has served as a model organism for the study of this process. Recently, many of the proteins that mediate E. coli nucleotide excision have ...

The excision of radiation-induced lesions in DNA by a DNA repair enzyme complex, namely the UvrABC nuclease complex, has been investigated. Irradiated DNA was treated with the enzyme complex. DNA fractions were analyzed by gas chromatography/isotope-dilut...

A general method has been developed to measure the formation and removal of DNA adducts in defined sequences of mammalian genomes. Adducted genomic DNA is digested with an appropriate restriction enzyme, treated with Escherichia coli UvrABC excision nuclease (ABC excinuclease), subjected to alkaline gel ...

The uvrA, uvrB, and uvrC genes control excision repair in Escherichia coli. Cells with mutations in any of these three genes cannot repair DNA by nucleotide excision. When the purified gene products--the UvrA, UvrB, and UvrC proteins--are mixed together, an excision nuclease is formed that incises on both sides of ...

Human cell free extract prepared by the method of Manley et al. carries out repair synthesis on UV-irradiated DNA. Removal of pyrimidine dimers by photoreactivation with DNA photolyase reduces repair synthesis by about 50%. With excess enzyme in the reaction mixture photolyase reduced the repair signal by the same amount even in the absence of photoreactivating light, presumably by binding to ...

A process for excising from a genomic DNA a complete sequence for encoding a protein which comprises treating a genomic DNA susceptible to mung bean nuclease and formamide under controlled conditions in a reaction mixture comprising mung bean nuclease and formamide in an amount sufficient for excising in a single ...

Hexavalent chromium [Cr(VI)] is an ubiquitous environmental contaminant and a well-known etiological agent of human lung cancer. Inside human cells, Cr(VI) is reduced to Cr(III), which can conjugate with amino acids, ascorbic acids, and glutathiones in the cytoplasm. Conjugated and unconjugated Cr(III) can enter the nucleus to form adducts with DNA and electrostatically interact with the phosphate ...

for Exo- and Endo-Nucleases The ABC of DNA repair Small Angle X-ray Scattering (the book) Nitric Oxide Synthase is the PDB Molecule of the Month Photos QuestionSix.jpg...

DNA-protein crosslinks are relatively common DNA lesions that form during the physiological processing of DNA by replication and recombination proteins, by side reactions of base excision repair enzymes, and by cellular exposure to bifunctional DNA-damaging agents such as platinum compounds. The mechanism by which pathological DNA-protein crosslinks are repaired in humans is ...

repair (BER), mismatch excision repair (MMR), nucleotide excision repair (NER), and other DNA repair), modulation of nucleotide pools (MNP), nucleotide excision repair (NER), nonhomologous end joining (NHEJ), Rad), editing and process- ing nucleases (EPN), homologous repair (HR), mismatch ...

DNA�protein crosslinks are relatively common DNA lesions that form during the physiological processing of DNA by replication and recombination proteins, by side reactions of base excision repair enzymes, and by cellular exposure to bifunctional DNA-damaging agents such as platinum compounds. The mechanism by which pathological DNA�protein crosslinks are repaired in humans ...

The conserved bacterial protein RloC, a distant homologue of the tRNA^Lys anticodon nuclease (ACNase) PrrC, is shown here to act as a wobble nucleotide-excising and Zn⁺⁺-responsive tRNase. The more familiar PrrC is silenced by a genetically linked type I DNA restriction-modification (R-M) enzyme, activated by a ...

-Induced Conformational Heterogeneity and Nucleotide Excision Repair, Srinivasa Rao Meneni, Steven M. Shell,� Lan Gao of Escherichia coli UvrABC-based nucleotide excision repair in a conformation-specific manner: i.e., greater, nucleotide excision repair; AF, aminofluorene adduct ...

by physical analysis in this manner. Isolation and Digestion of Yeast Nuclei l-liter cultures of yeast cells of centromere homology is resistant to nuclease digestion. Restriction enzyme linkers encod- ing the Bam HI- crococcal nuclease digestion (Bloom and Carbon, 1982). This complex is centered around the conserved CDE III

Nucleotide Excision Repair Srinivasarao Meneni, Steven M. Shell, Yue Zou, and Bongsup P. Cho*, DepartmentABC-based nucleotide excision repair (NER) in a conformation-specific manner. The 19 F NMR/NER results indicate greater of the bulky AAF requires bypass polymerases (6). Nucleotide excision repair (NER) of the ...

A 28-year-old man presented with proptosis and medial displacement of the right eye, intermittent pain, and diplopia of 1 month's duration. Radiologic examination demonstrated a mass in the right lateral orbit resembling an aneurysmal bone cyst (ABC). Histopathologic evaluation of the surgically excised lesion via orbitotomy confirmed the radiologic ...

8,5'-Cyclopurines, making up an important class of ionizing radiation-induced tandem DNA damage, are repaired only by nucleotide excision repair (NER). They accumulate in NER-impaired cells, as in Cockayne syndrome group B and certain Xeroderma Pigmentosum patients. A plasmid containing (5'S)-8,5'-cyclo-2'-deoxyguanosine (S-cdG) was replicated in Escherichia coli with specific ...

The XPF/MUS81 family of endonucleases is found in eukaryotes and archaea, in the former they play a critical role in DNA repair and replication fork restart. Hef is a XPF/MUS81 family member found in Euryarchaea and is related to the Fanconi anemia protein FANCM. We have studied the role of Hef in the euryarchaeon Haloferax volcanii. Unlike Xpf in eukaryotes, Hef is not involved in nucleotide ...

8,5?-Cyclopurines, making up an important class of ionizing radiation-induced tandem DNA damage, are repaired only by nucleotide excision repair (NER). They accumulate in NER-impaired cells, as in Cockayne syndrome group B and certain Xeroderma Pigmentosum patients. A plasmid containing (5?S)-8,5?-cyclo-2?-deoxyguanosine (S-cdG) was replicated in Escherichia coli with specific ...

Progress is reported on studies related to molecular mechanisms for radiation damage to cells. Mung bean nuclease was shown to excise the A + T rich regions from different species of DNA exposed to premelting temperatures. This suggests an additional application of mung bean nuclease as a means of detection of slightly ...

is acyclic then G has one and only one SPNE. Let G = (A,V,,) with A = {1,2}, V = {a,b,c}, 1 = {a,c}, 2 = {b}, 1 = a;(�b,c) , 2 = (�b,�c);�a . P1 Disc abc abc abc abc abc abc abc abc ...

DNA damage and repair in response to ultraviolet light (UV) or furocoumarin photoadducts were studied in cultured primate cells. First, the sensitivity to digestion by the enzyme staphylococcal nuclease (SN) of repair patches synthesized in response to damage by UV or the angular furocoumarin angelicin was examined in human cells. Second, excision repair ...

The C2?-oxidized abasic lesion (C2-AP) is produced in DNA that is subjected to oxidative stress. The lesion disrupts replication and gives rise to mutations that are dependent upon the identity of the upstream nucleotide. Ape1 incises C2-AP, but the 5?-phosphorylated fragment is not a substrate for the lyase activity of DNA polymerase ? (Pol ?). Excision of the lesion is ...

cis-Platinum compounds, which are used in cancer chemotherapy, are thought to exert their effect by damaging DNA. It is known that this damage is partially repaired in Escherichia coli. Using cis-Pt-treated pBR322 DNA as a probe, we investigated the role of nucleotide excision repair in the removal of Pt-DNA adducts. We found that the nucleotide excision ...

cis-Platinum compounds, which are used in cancer chemotherapy, are thought to exert their effect by damaging DNA. It is known that this damage is partially repaired in Escherichia coli. Using cis-Pt-treated pBR322 DNA as a probe, the role of nucleotide excision repair in the removal of Pt-DNA adducts was investigated. It was found that the nucleotide ...

Crude extracts of human KB cells grown in suspension culture contain enzyme activity that catalyzes the preferential excision of thymine-containing pyrimidine dimers from uv-irradiated E. coli DNA specifically incised adjacent to dimer sites. Fractionation of KB cell crude extracts reveals the presence of three such activities with distinct affinities for both DEAE-cellulose ...

XPF/Rad1/Mus81/Hef proteins recognize and cleave branched DNA structures. XPF and Rad1 proteins cleave the 5' side of nucleotide excision repair bubble, while Mus81 and Hef cleave similar sites of the nicked Holliday junction, fork, or flap structure. These proteins all function as dimers and consist of catalytic and helix-hairpin-helix DNA binding (HhH) domains. We have ...

We have exposed confluent normal human fibroblasts to ultraviolet (UV) fluences of 5, 14, or 40 J/m/sup 2/ and monitored the specific activity of post-uv repair synthesis in chromatin with (/sup 3/H)thymidine pulses. We have shown that under conditions where no semiconservative deoxyribonucleic acid (DNA) synthesis is detectable, the specific activity of repair label one-fifth that in bulk DNA at ...

Gene flow from transgenic plants is an environmental and regulatory concern. While biocontainment might be achieved using male sterility or transgenic mitigation tools, we believe that perhaps the optimal solution might be simply to remove transgenes from pollen. Male sterility might not be ideal for many pollinators, and might not be implementable using standardized genes. Transgenic mitigation ...

In normal human cells the amount of excision of ultraviolet damage to DNA saturates at high doses. In these cells some chemicals mimic ultraviolet damage as far as their biological and repair characteristics are concerned. One of these chemicals is N-acetoxy-2-acetylaminofluorene. We determined whether the limited repair capacity for ultraviolet damage was affected by ...

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Escherichia coli has several overlapping DNA repair pathways which act in concert to eliminate the DNA damage caused by a diverse array of physical and chemical agents. The ABC excinuclease which is encoded by the uvrA, uvrB, and uvrC genes mediates both the incision and excision steps of nucleotide excision repair. Traditionally, this ...

Caffeine potentiates the mutagenic and lethal effects of genotoxic agents. It is thought that this is due, at least in some organisms, to inhibition of DNA repair. However, direct evidence for inhibition of repair enzymes has been lacking. Using purified Escherichia coli DNA photolyase and (A)BC excinuclease, we show that the drug inhibits photoreactivation and nucleotide ...

Caffeine potentiates the mutagenic and lethal effects of genotoxic agents. It is thought that this is due, at least in some organisms, to inhibition of DNA repair. However, direct evidence for inhibition of repair enzymes has been lacking. Using purified Escherichia coli DNA photolyase and (A)BC excinuclease, we show that the drug inhibits photoreactivation and nucleotide ...