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)

Five broad host range lipid-containing bacteriophages PRD1, PR3, PR4, PR5 and L17 isolated from different parts of the world were compared using biological and structural criteria. Virus morphology as well as genome sizes appeared to be identical. However, these viruses could be distinguished by restriction endonuclease mapping and by their structural protein patterns in SDS--gel electrophoresis. The viruses studied thus form a very close group of lipid-containing bacteriophages. We suggest PRD1 as a model organism for this group and that the group be called the PRD1 phage group.
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PMID:Comparison of the lipid-containing bacteriophages PRD1, PR3, PR4, PR5 and L17. 732 Jul 7

Hepatitis B virus DNA contains a tightly bound protein which was not removed by healing to 60 degrees C with 2% SDS, 2% mercaptoethanol. The protein was indirectly demonstrated by the extraction of the DNA-protein complex with phenol before but not after its digestion with proteinase K. The DNA-protein complex had a lower buoyant density than protease-treated or free DNA; it was bound to glass fiber filters; it migrated at a slower rate in gel electrophoresis; and it could be radiolabeled by oxidative iodination. The binding site of the protein was mapped by extraction of restriction endonuclease digests with phenol and analysis of the digests for missing DNA fragments. The protein was localized to a site near the 5' end of the complete viral DNA strand. It remained attached to this strand after heating with SDS to 90 degrees C or treatment with 0.1 N NaOH, suggesting a covalent linkage. The 5' end of neither viral DNA strand could be phosphorylated in a reaction with polynucleotide kinase, consistent with attachment of protein to the 5' ends. The incomplete DNA strand, however, which is the strand elongated by the virion DNA polymerase reaction, did not contain a detectable amount of polypeptide as did the complete strand. The reasons for the apparent block of the 5' end of the incomplete DNA strand is thus not known. The protein bound covalently to HBV DNA could be involved in the replication of the complete viral DNA strand and/or endonucleolytic generation of linear unit-length DNA pieces from replicative intermediates, although its function and origin are not yet known.
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PMID:Hepatitis B virus contains protein attached to the 5' terminus of its complete DNA strand. 743 7

Activation of a triplet of nuclear proteins (NP42-50) was observed in human Jurkat T cell line following treatment with an antibody to CD95 (Fas/Apo-1), a cell surface molecule involved in apoptotic cell death. The nuclease activity, corresponding to a triplet of proteins observed at approximately 42, 45, and 50 kDa in size, was extractable, heat-stable, and detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis containing deoxyribonucleic acids (SDS-PAGE-DNA) assay. The NP42-50 activity requires the presence of Mg2+/Ca2+ and is insensitive to inactivation by heating at 80 degrees C for 5 min. Zinc effectively inhibited the enzymatic activity of NP42-50 on SDS-PAGE-DNA and also protected Jurkat cells from the CD95-mediated apoptosis in cell cultures. The nuclease activation, however, was not a unique pathway for the CD95-mediated cell death. The apoptosis induced by arabinofuranosyl cytosine, a chemotherapeutic agent, also activated the NP42-50 nuclease activity in Jurkat cells, suggesting that a similar cascade of subsequent events in apoptosis may occur in most instances although many different signals can initiate apoptotic cell death in various cell types. The nuclease identified by this study appears to be distinguishable from DNase I or DNase II by its molecular characteristics and its enzymatic requirements. The NP42-50, with respect to the nuclease activity closely associated with apoptotic cell death, may serve as a candidate for the endonuclease(s) involved in the cleavage of DNA into fragments during apoptosis.
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PMID:A triplet of nuclease proteins (NP42-50) is activated in human Jurkat cells undergoing apoptosis. 755 79

The ability of yeasts to ferment cellodextrins is rare. Candida wickerhamii is able to use these sugars for alcohol production because of a cell-bound, extracellular, beta-glucosidase that is unusual by not being inhibited by glucose. A cDNA expression library in lambda phage was prepared with mRNA isolated from cellobiose-grown C. wickerhamii. Immunological screening of the library with polyclonal antibodies against purified C. wickerhamii cell-bound, extracellular beta-glucosidase yielded 12 positive clones. Restriction endonuclease analysis and sequence data revealed that the clones could be divided into two groups, bglA and bglB, which were shown to be genetically distinct by Southern hybridization analyses. Efforts were directed at the study of bglB since it appeared to code for the cell-bound beta-glucosidase. Sequence data from both cDNA and genomic clones showed the absence of introns in bglB. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of cell lysates from Escherichia coli bglB clones confirmed the presence of an expressed protein with an apparent molecular mass of 72 kDa, which is consistent with that expected for an unglycosylated form of the enzyme. Amino acid comparisons of BglB with other beta-glucosidase sequences suggest that it is a member of family 1 glycosyl hydrolases but is unusual in that it contains an additional 100 to 130 amino acids at the N terminus. This sequence did not have homologies to other known protein sequences and may impart unique properties to this beta-glucosidase.
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PMID:Cloning and characterization of a gene encoding a cell-bound, extracellular beta-glucosidase in the yeast Candida wickerhamii. 757 90

The 2nd endonuclease (nuclease Le3) which hydrolyzes both RNA and heat denatured DNA to 5'-nucleotides was purified from the fruit bodies of Lentinus edodes to a homogeneous state by SDS PAGE. The nuclease was different from the nuclease Le1 previously characterized [H. Shimada et al. Chem. Pharm. Bull., 39, 2633-2637 (1991)] in molecular weight, optimal pH and N-terminal amino acid sequence. The N-terminal amino acid sequence of nuclease Le3 analyzed up to the 20th residue showed that 50% of the amino acid residues are identical to nuclease Le1.
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PMID:Purification and characterization of the 2nd 5'-nucleotide-forming nuclease from Lentinus edodes. 761 9

DNA endonucleases in rat liver nuclei extracts were examined by SDS-polyacrylamide gel electrophoresis followed by zymogram analysis. Four polypeptides of 120, 54, 31 and 28 kDa, which have DNA endonuclease activity, were shown to occur in the extract isolated in the presence of phenylmethanesulfonyl fluoride (PMSF), a proteinase inhibitor. Isolation without PMSF, as well as storage at -20 degrees C, or autodigestion, resulted in multiplication of active polypeptides in the extracts. Trypsin digestion led to the appearance of an active > 140 kDa polypeptide, indicating the existence of a potential endonuclease precursor in the nuclear extract.
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PMID:In vitro proteolysis of endonucleases in rat liver nuclei extracts. 766 99

The aim of this study was to find out if reinfection or recrudescence accounted for the recurrence of Helicobacter pylori infections after apparent eradication of the bacterium. Three hundred and twenty patients were treated with colloidal bismuth subcitrate (120 mg four times daily for four weeks), metronidazole and tetracycline (400 mg and 500 mg, respectively, thrice daily for the first week). H pylori was eradicated four weeks after the end of treatment as assessed by the rapid urease test, histological examination, Gram staining, and culture. However, the infection recurred in 29 (9.1%) of the patients one year after apparent eradication. Pre and posteradication isolates from five patients were available. DNA was extracted and used for restriction endonuclease analysis with Hind III and Hae III, and for polymerase chain reaction (PCR) based randomly amplified polymorphic DNA fingerprinting with a combination of two 10 nucleotide primers. Sodium dodecyl sulphate polyacrylamide gel electrophoretic analysis was performed also. Randomly amplified polymorphic DNA fingerprinting was unique in that it yielded highly discriminatory fingerprints, which showed that the pretreatment and recurrent isolates obtained from each of the five patients were indistinguishable from one another. This shows that recurrence of H pylori infection is probably caused by recrudescence and that the discriminatory power of randomly amplified polymorphic DNA fingerprinting is a practicable and discriminatory typing scheme for H pylori.
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PMID:Recrudescence of Helicobacter pylori after apparently successful eradication: novel application of randomly amplified polymorphic DNA fingerprinting. 767 75

We have previously shown that in developing chicken embryos and differentiating mouse myoblasts, the demethylation of 5-metCpGs occurs through the replacement of 5-methylcytosine by cytosine (Jost, J. P. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 4685-4688; Jost, J. P. & Jost, Y.C. (1994) J. Biol. Chem. 269, 10040-10043). We have now purified over 30,000-fold a 5-methylcytosine-DNA glycosylase from 12-day-old chicken embryos. The enzyme copurifies with a mismatch-specific thymine-DNA glycosylase and an apyrimidic-endonuclease. The reaction product of the highly purified 5-methylcytosine-DNA glycosylase is 5-methylcytosine. The copurified apyrimidic-endonuclease activity cleaves 3' from the apyrimidic sugar. A 52.5-kDa peptide, isolated as a single band from preparative SDS-polyacrylamide gels, has both the 5-methylcytosine-DNA glycosylase and the mismatch-specific thymine-DNA glycosylase activities. 5-Methylcytosine-DNA glycosylase has an apparent pI of 5.5-7.5 and maximal activity between pH 6.5 and 7.5. The Km for hemimethylated oligonucleotide substrate is 8 x 10(-8) M with a Vmax of 4 x 10(-11) mol/h/micrograms proteins. 5-Methylcytosine-DNA glycosylase binds equally well to methylated and non-methylated DNA. The enzyme reacts six times faster with the hemimethylated DNA than with the same bifilarly methylated DNA sequence, and single-stranded methylated DNA is not a substrate. The action of the enzyme is distributive.
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PMID:Mechanisms of DNA demethylation in chicken embryos. Purification and properties of a 5-methylcytosine-DNA glycosylase. 773 Mar 51

Restriction endonuclease analysis was used as a new method to obtain genomic DNA fingerprints in yeast. Fifteen yeast strains belonging to the genera Saccharomyces and Zygosaccharomyces were examined. Restriction fragments obtained with ApaI or KspI endonucleases were separated by SDS-PAGE and silver-stained. Analysis of the fingerprints showed that restriction enzyme digestion of genomic DNA can be successfully applied to yeast, enabling the differentiation between strains belonging to different or to the same species or genera.
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PMID:DNA fingerprinting of yeast strains by restriction enzyme analysis. 774 55

A duck parvovirus (DPV) isolated from muscovy ducks during the epizootic in France in 1989 was purified from inoculated allanto-amniotic fluids by CsCl density gradient centrifugation and characterized. Full and empty non-enveloped icosahedral viral particles were observed banding at densities of 1.39 to 1.42 and 1.38 respectively, with a diameter of 22 to 23 nm. Viral proteins were analyzed by SDS-PAGE and the estimated molecular weights of the 3 major proteins were 91, 78 and 58 kDa. The nucleic acid was shown to be a single-stranded DNA of about 5,300 bases with terminal palindromic hairpins. These results confirm the previous classification of the virus in the family Parvoviridae established by Jestin et al. [14] on morphological and serological bases. The DPV DNA was reannealed indicating that complementary DNA strands were encapsidated. A partial restriction endonuclease map was also established. This work constitutes the first biochemical and genomic description of a muscovy duck parvovirus.
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PMID:Biochemical and genomic characterization of muscovy duck parvovirus. 782 5


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