Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.30.2 (endonuclease)
18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Multiple flat wart-like lesions of a renal allograft recipient were shown to contain HPV 3 or a serologically crossreacting virus by indirect immunofluorescence with monospecific animal antisera against HPV [1--5]. The patient's serum revealed virus specific antibodies (immunofluorescence titer 1/80). Papillomaviruses were isolated and after in vitro iodination 3 major proteins (MW 70.000, 56.000 and 43.000) were detected by SDS polyacryalmide gel electrophoresis. DNA was extracted from the warts and cleaved with the restriction endonuclease Hae III. Distinct bands were discernible within the background of cellular DNA and these fragments were identified as papillomavirus DNA by blot hypbridization with 32P-labeled viral DNA.
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PMID:Characterization of human papillomavirus 3 in warts of a renal allograft patient. 22 66

An endonuclease that can act on calf thymus DNA and circular doublestranded phage PM2 DNA has been isolated from HeLa S3 cell chromatin. Approximately 200-fold purification was achieved by a sequence of subcellular fractionation, differential NaCl solubility and chromatography on CM-Sephadex, DEAE-cellulose and hydroxyapatite, and isoelectric point is pH 5.1 +/- 0.2. Divalent cations are necessary for its activity and the enzyme is heat inactivated at 60 degrees C. The enzyme activity is sensitive to caffeine and sulfhydryl reacting compounds. The molecular weight, determined by gel filtration and SDS gel electrophoresis, is approx. 22 000.
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PMID:Purification and properties of a nuclear DNA endonuclease from HeLa S3 cells. 44 34

DNA polymerase III from Bacillus subtilis has been purified about 4,500-fold. Disc gel electrophoresis of the purified fraction reveals a single major protein band which co-migrates with the polymerase activity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the polymerase yields a single, 166,000 dalton band. The hydrodynamic properties of the enzyme are ionic strength-dependent. The average values from determinations in high and low salt are 7.6 S for the sedimentation coefficient and 52 A for the Stokes radius. These two parameters indicate a molecular weight for the native enzyme of 160,000. Therefore, the enzyme appears to contain a single, long, polypeptide chain. The enzyme has no endonuclease activity but does have single strand specific exonuclease activity. Hydrolysis is initiated exclusively from the 3' terminus yielding 5' mononucleotides, and a dinucleotide is the limit of digestion. The exonuclease activity has an ionic strength dependence of pH optimum similar to that of the polymerase but appears to be more fastidious in its divalent metal requirement. The mode of attack by the enzyme is strictly distributive. The activity of the exonuclease decreases markedly with increasing substrate size. Two opposing mechanisms account quantitatively for this effect--intrinsic competitive inhibition by interior substrate nucleotides and increasing accessibility of the substrate terminus to the enzyme with increasing chain length. The polymerase synthesizes DNA in the 5' leads to 3' direction and the apparent Km for each of the deoxyribonucleoside triphosphates is about 1 muM. The polymerase replicates RNA-primed, phiX174 DNA in the presence of Escherichia coli elongation Factors I and II. In contrast to polymerase III, B. subtilis DNA polymerase II has no detectable nuclease activity.
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PMID:Purification and characterization of DNA polymerase III from Bacillus subtilis. 81 56

The freshly prepared crude cytoplasmic fraction of aqueously extracted KB cells contains a single major species of DNA polymerase activity (DNA polymerase C) that sediments homogeneously in low ionic strength sucrose gradients with a peak at 10.8 S. The enzyme activity from frozen crude extracts sediments heterogeneously under these conditions with peaks at 8.4 and 10 S. In 0.45 M salt-containing gradients all of the polymerase activity is recovered as a single 6.4 S species. When purified to a specific activity of 7,300, DNA polymerase C sediments in low ionic strength gradients as a single species of 6.5 S. From combined sedimentation and gel filtration analysis, we estimate the molecular weight of the active protomeric species of the polymerase to be about 170,000. Under no conditions of ionic strength does the enzyme disaggregate to active species smaller than 6.4 to 6.5 S. Sodium dodecyl sulfate-polyacrylamide gel analysis of the most highly purified enzyme fractions reveals two major protein bands of 87,000 and 175,000 daltons, respectively. These data suggest that DNA polymerase C contains an 87,000-dalton component and permit the interpretation that the active protomer of Mr equal 170,000 may be a dimer. The purified enzyme shows maximal activity with gapped duplex DNA and has an absolute requirement for 3'-hydroxyl termini. It utilizes initiated polydeoxynucleotide templates poorly and initiated polyribonucleotide templates not at all. Although the polymerase is inhibited by PPi it has only minimal ability to promote PPi exchange (0.8% of the polymerase activity). The purified enzyme is free of endonuclease and exonuclease activities (less than or equal to 0.003% of the polymerase activity) and demonstrates no primer-template-dependent conversion of substrate dNTP to free dNMP during the polymerization reaction. Finally, DNA polymerase C does not excise misparied primer termini from a synthetic homopolymer primer-template but can utilize such termini as initiation sites, although at a very slow rate.
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PMID:"Cytoplasmic" deoxyribonucleic acid polymerase. Structure and properties of the highly purified enzyme from human KB cells. 109

CeqI, a type II restriction endonuclease, an isoschizomer of EcoRV was purified to apparent homogeneity by a combination of salt precipitation, ion exchange, dye affinity and hydrophobic interaction chromatographies. The crude enzyme was present in the form of large aggregates that could be pelleted by high speed centrifugation. The enzyme was not associated with cellular membranes, though non-ionic detergents lowered the apparent size of the aggregates. The purified enzyme also showed a tendency to form large molecular mass (66-600 kDa) complexes under physiological conditions, in the absence of cleavable DNA. The enzyme formed smaller complexes in the presence of DNA and non-ionic detergents and dissociated into subunits (and undergoes reversible loss of activity) in the presence of high concentrations of salts. According to SDS gel electrophoresis and sedimentation analysis the molecular mass of the monomer 32 +/- 2 kDa. The enzyme had a rather broad PH optimum, extending into the alkaline range and lost specificity and activity in buffers below pH 6.
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PMID:Purification and characterization of CeqI restriction endonuclease. 128 28

A G-to-A transition at nucleotide pair (np) 7444 in the mtDNA was found to correlate with Leber hereditary optic neuropathy (LHON). The mutation eliminates the termination codon of the cytochrome c oxidase subunit I (COI) gene, extending the COI polypeptide by three amino acids. The mutation was discovered as an XbaI restriction-endonuclease-site loss present in 2 (9.1%) of 22 LHON patients who lacked the np 11778 LHON mutation and in 6 (1.1%) of 545 unaffected controls. The mutant polypeptide has an altered mobility on SDS-PAGE, suggesting a structural alteration, and the cytochrome c oxidase enzyme activity of patient lymphocytes is reduced approximately 40% relative to that in controls. These data suggest that the np 7444 mutation results in partial respiratory deficiency and thus contributes to the onset of LHON.
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PMID:A mitochondrial DNA variant, identified in Leber hereditary optic neuropathy patients, which extends the amino acid sequence of cytochrome c oxidase subunit I. 132 38

Mycoplasma synoviae (MS) isolates made in 1988-89 from turkey flocks in North Carolina, Missouri, and Ontario, Canada, were compared with each other and MS reference strains (WVU-1853, F10-2AS, Neb-3S, and K1968) by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of cell proteins and restriction endonuclease analysis (REA) of DNA. SDS-PAGE and REA indicated considerable homology among MS reference strains and recent field isolates. However, sufficient differences were resolved to identify the MS reference strains as different from each other and the field isolates, and to classify seven of nine recent field isolates as a cluster of nearly identical strains. The results suggest that flocks infected with members of the cluster were epizootiologically associated, possibly by a common or point source of infection.
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PMID:An outbreak of Mycoplasma synoviae infection in North Carolina turkeys: comparison of isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and restriction endonuclease analysis. 132 12

A mitochondrial endonuclease from Drosophila melanogaster embryos was purified to near homogeneity by successive fractionation with DEAE-cellulose and heparin--avidgel-F, followed by FPLC chromatography on mono S, Superose 12 and a second mono S column. This enzyme digests double-stranded DNA more efficiently than heat-denatured DNA. The endonuclease activity has a molecular mass of 44 kDa, as determined under native conditions using a gel-filtration Superose 12 column. The prominent peptide detected by SDS/polyacrylamide gel electrophoresis likewise has a molecular mass of 44 kDa, suggesting a monomeric protein. The enzyme has an absolute requirement for divalent cations, preferring Mg2+ over Mn2+. No activity could be detected when these cations were replaced by Ca2+ or Zn2+. The pH optimum for this enzyme activity is 6.5-7.4 and its isoelectric point is 4.9. Both single-strand and double-strand breaks are introduced simultaneously into a supercoiled substrate in the presence of MgCl2 or MnCl2. Endonuclease-treated DNA serves as a substrate for DNA polymerase I from Escherichia coli, suggesting that 3'-OH termini are generated during cleavage. The enzyme is free from any detectable DNA exonuclease activity but not from RNase activity. Partial inhibition by antibodies raised against mitochondrial endonucleases derived from bovine heart and Saccharomyces cerevisiae have revealed a potential structural homology between these nucleases.
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PMID:Purification and characterization of a mitochondrial endonuclease from Drosophila melanogaster embryos. 133 52

The mechanism of intracellular deoxyribonucleotide triphosphates (dNTP) pool imbalance-induced cell death in mouse FM3A cells was studied. When the cells were treated with 1 microM 5-fluorodeoxyuridine (FdUrd), the imbalance of the cellular dNTP pool was induced. The imbalance was followed by DNA double stranded breaks and subsequent cell death. The endonuclease toward double stranded DNA has been found in a fraction of FdUrd treated cell lysate, and isolated using column chromatography. SDS-polyacrylamide gel electrophoresis showed a major protein species of approximate 45 kDa. The endonuclease was revealed, using electrophoretic separation in SDS-polyacrylamide gels containing DNA, by incubating the gels in buffer to remove SDS and to allow renaturation and enzyme activity.
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PMID:dNTP pool imbalance induced endonuclease: 5-fluorodeoxyuridine induced DNA double strand break in mouse FM3A cells and the mechanism of cell death. 133 86

A nuclease that could be recovered from the supernatant of cultures, as well as from cell-free extracts, of the cyanobacterium Anabaena sp. PCC 7120 was identified as a 29 kDa polypeptide by its ability to degrade DNA after electrophoresis in DNA-containing SDS-polyacrylamide gels. Some clones of a gene library of strain PCC 7120 established in Escherichia coli were found to produce the 29 kDa nuclease. The nucA gene encoding this nuclease was subcloned and sequenced. The deduced polypeptide, NucA, had a molecular weight of 29,650, presented a presumptive signal peptide in its N-terminal region and showed homology to the products of the nuc gene from Serratia marcescens and the NUC1 gene from Saccharomyces cerevisiae. The NucA protein from Anabaena itself, or from the cloned nucA gene expressed in E. coli, catalysed the degradation of both RNA and DNA, had the potential to act as an endonuclease, and functioned best in the presence of Mn2+ or Mg2+. An Anabaena nucA insertional mutant was generated which failed to produce the 29 kDa nuclease.
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PMID:Identification, genetic analysis and characterization of a sugar-non-specific nuclease from the cyanobacterium Anabaena sp. PCC 7120. 134 21


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