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)

During vaccinia virus (VV) assembly a major polypeptide migrating with an apparent MW of 35K, designated Ag35, is expressed as an early function and becomes an integral component of the lipoprotein envelope surrounding the mature virion. In a previous study evaluating humoral immunity to VV, a prominent response against Ag35 was invariably detected in immunized mice. In the context of our continuing investigations of the structure and function of the vaccinia envelope, with a view to alteration in antigenicity of this agent when used as a vaccine vector for foreign antigens, we carried out detailed mapping of the Ag35 gene, as well as determination of the nucleotide sequence. Use of hybridization-arrested translation, coupled with immunoprecipitation, located this gene within a 2.7-kbp EcoRI fragment of the larger 8.7-kbp HindIII H fragment. By means of S1 endonuclease resistance analysis a viral transcript was identified at the site of the Ag35 gene, where the occurrence of an open reading frame (ORF), corresponding to the transcript, was deduced from DNA sequence determination. However, the ORF encodes a polypeptide of only 22,300 Da predicted MW, which is much lower than the apparent MW estimated from SDS-polyacrylamide gel electrophoresis. The size discrepancy is not due to glycosylation or phosphorylation of Ag35 but may result from a proline-rich sequence which occurs in this polypeptide. To confirm that the ORF recognized in this study does, indeed, encode Ag35, the gene was expressed as a beta-galactosidase fusion protein in pUC19; Escherichia coli transformed with the relevant clones expressed a polypeptide of the appropriate molecular weight and antigenicity, when tested by Western blots. Regarding secondary structure and hydropathicity it can be predicted from the DNA sequence that Ag35 is highly hydrophilic but contains a hydrophobic region at the carboxy terminus, perhaps providing the stretch involved in membrane insertion. Computer search of a bank of protein sequences revealed an unusually strong similarity of 68% between the Ag35 at amino acid positions 44-121 and the G glycoprotein of respiratory syncytial virus at positions 189-264.
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PMID:Molecular characterization of a prominent antigen of the vaccinia virus envelope. 246 5

An endonuclease endogenous to rat-liver nuclei has been purified by a series of chromatographic procedures and finally by isoelectric focusing (IEF) electrophoresis. The nuclease fraction prepared by the IEF electrophoresis (IEF fraction) showed a pI value of 5.7 and migrated as a single band to a molecular weight position of 46,000 on an SDS-polyacrylamide gel. The activity for single-stranded DNA was enhanced by 10 mM MgCl2 and/or by 5-15 mM MgCl2 in the presence of 2 mM CaCl2 (an optimum pH, 7.0), but was lowered by CaCl2 alone and inhibited strongly by ZnCl2 or MnCl2. The activity for duplex DNA was rather low, although an optimum condition was 10 mM MgCl2. In fact, even under this condition, the activity was about 40% lower than that for single-stranded DNA. Moreover, the IEF fraction formed single-strand nicks much more rapidly than double-strand cuts in pBR322 DNA, and preferentially produced deoxyadenosine 5'-monophosphate termini in the DNA. In addition, RNAase activity was also detected in this fraction.
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PMID:Purification and properties of an endonuclease endogenous to rat-liver nuclei. 254 36

A non-occluded baculovirus was isolated from nymphs of the field cricket, Gryllus rubens. SDS-polyacrylamide gel electrophoresis revealed the presence of 6 major and 11 minor polypeptides in these particles. Restriction endonuclease analysis indicated that the genome, 87.0 +/- 1.8 kilobase pairs, was a closed circular DNA molecule. DNA-DNA hybridization in low strigency conditions revealed no homology with the genomes of Oryctes baculovirus or Autographa california NPV. The virus replicated in nuclei of fat body cells, and was transmitted per os to a small proportion of first instar G. rubens nymphs.
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PMID:Characterization of a non-occluded baculovirus (subgroup C) from the field cricket, Gryllus rubens. 254 63

We have purified a cruciform DNA resolving endonuclease (Endo X3) greater than 1000-fold from crude extracts of mitotically growing Saccharomyces cerevisiae. The enzyme shows high specificity for DNAs with secondary structures and introduces characteristic patterns of staggered 'nicks' in the immediate vicinity of the structure. The following substrates were analyzed in detail: (i) naturally occurring four-way X junctions in cruciform DNA of a supercoiled plasmid; (ii) synthetic four-way X junctions with arms of 9 bp; (iii) synthetic three-way Y junctions with arms of 10 bp; and (iv) heteroduplex loops with 19 nucleotides in the loop. Cleavages were always found in the double stranded portion of the DNA, located immediately adjacent to the junction of the respective structure. The Endo X3 induced cleavage patterns are identical or very similar to the cleavage patterns induced in the same substrates by endonuclease VII (Endo VII) from phage T4. Furthermore, the activity of Endo X3 is completely inhibited in the presence of anti-Endo VII antiserum. Endo X3 has an apparent mol. wt of 43,000 daltons, determined by gel filtration and of approximately 18,000 daltons in SDS--polyacrylamide gels. Maximum activity of the enzyme was obtained in the presence of 10 mM MgCl2 at 31 degrees C in Tris-HCl buffer over a broad pH range with a maximum approximately 8.0. About 70% of maximal activity was obtained when Mg2+ was replaced by equimolar amounts of Mn2+ or Ca2+.
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PMID:Cruciform cutting endonucleases from Saccharomyces cerevisiae and phage T4 show conserved reactions with branched DNAs. 255 68

Bovine herpesvirus 1 (BHV-1) isolates from respiratory tract and from vagina of bovine in Japan were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and the DNA restriction endonuclease cleavage pattern, and compared with European BHV-1 strains. Both protein profile and DNA cleavaged pattern of BHV-1 isolates from respiratory tract were the same as those of European infectious bovine rhinotracheitis (IBR) virus, whereas the protein profile and DNA cleavage patterns of one isolate (M1) from vagina was the same as those of the European infectious pustular vulvovaginitis (IPV) virus. The facts indicate that IPV virus has existed in Japan.
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PMID:A comparison of polypeptides and restriction endonuclease sites of BHV-1 isolates and identification of IPV virus in Japan. 255 74

A previously unreported endoribonuclease has been identified in Escherichia coli, which has a preference for hydrolysis of pyrimidine-adenosine (Pyd-Ado) bonds in RNA. It was purified about 7000-fold to give a single band after SDS/polyacrylamide gel electrophoresis; the eluted protein gave the same RNase specificity. The sizes of the native and denatured enzymes agreed suggesting that the enzyme exists as a monomer of approximately 26 kDa. It is called RNase M. The only other reported broadly specific endoribonuclease in E. coli is RNase I, a periplasmic enzyme. Based on differences in charge, heat stability and substrate specificity, it was clear that RNase M is not RNase I. The specificity of RNase M was remarkably similar to that of pancreatic RNase A even though the two enzymes differ in charge characteristics and size. Earlier studies had shown that mRNA from the lactose operon of E. coli is hydrolyzed in vivo primarily between Pyd-Ado bonds [Cannistraro et al. (1986) J. Mol. Biol. 192, 257-274] We propose that this major RNase activity accounts for these cleavages observed in vivo and that it is the endonuclease for mRNA degradation in E. coli.
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PMID:Purification and characterization of ribonuclease M and mRNA degradation in Escherichia coli. 265 29

Three strains of Salmonella enteritidis phage type 4 (PT4) and 33 strains of S. enteritidis phage type 7 (PT7) were examined for the ability to produce lipopolysaccharide (LPS) and for plasmid carriage. The LPS of all strains of PT4 gave a typical 'ladder' pattern by SDS-PAGE and silver staining, and on serotyping these strains were shown to express the O-antigens 9, 12. In contrast, strains of PT7 did not express long-chain LPS and were autoagglutinable. All strains of PT4 and the majority of strains of PT7 carried a single plasmid of 38 MDa, indistinguishable when characterised by restriction endonuclease fragmentation analysis. Epidemiological and experimental observations have demonstrated a relationship between strains of S. enteritidis PT4 and PT7, and our results, using mice, show that the loss of ability of strains of PT4 to snythesise LPS is responsible for the conversion of highly virulent strains of PT4 to avirulent strains of PT7. From epidemiological data of human infections in England and Wales, we suggest that strains of S. enteritidis PT7 may be less virulent for humans.
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PMID:Conversion of Salmonella enteritidis phage type 4 to phage type 7 involves loss of lipopolysaccharide with concomitant loss of virulence. 267 7

The genome of a 22 nm icosahedral phage which infects some avian Chlamydia psittaci strains recovered from domestic ducks has been characterized as a ss circular DNA molecule of about 4850 bases. The replicative form of this genome was isolated from purified chlamydial organisms. A restriction endonuclease cleavage site map of the genome was constructed from dsDNA synthesized in vitro from ss phage DNA and EcoRI fragments were then cloned into pUC9. The phage genome was detected only by Southern blot hybridization in C. psittaci which was productively infected with phage; no evidence was found for the integration of phage DNA into the chlamydial chromosome. Three viral polypeptides, of approximate Mr values 75K, 30K and 16.5K were identified when phage was analysed by SDS-PAGE. This virus, which we have designated Chp 1, is either an aberrant member of the Microviridae or the first member of a new bacteriophage family.
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PMID:Further characterization of a bacteriophage recovered from an avian strain of Chlamydia psittaci. 273 18

A single-strand-specific endonuclease which converted negatively supercoiled DNA to open-circular and linear DNA was purified to homogeneity with Hb-Sepharose 4B, DEAE Trisacryl M, HA-Ultrogel and PBE-94 chromatofocusing from extracts of Streptomyces tendae ATCC 31160. Bio-Gel P-200 chromatography and electrophoresis in SDS-PAGE indicated the native protein was a monomer with a molecular weight of approximately 40-kDa. This enzyme did not hydrolyze double-stranded linear DNA but digested RNA and circular single-strand DNA. Sequence specificity for nicking of negatively supercoiled DNA was not detected.
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PMID:Purification and characterization of an endonuclease (E.C. 3.1.30.1) from Streptomyces tendae. 283 46

An endonuclease was purified from the cap tissues of basidiocarp of Coprinus cinereus collected at early meiotic prophase. It has an optimal activity at pH 7.0 and 37 degrees C. It is a cationic enzyme with a molecular mass of 22 kDa by gel filtration, and contains a 12-kDa and a 14-kDa peptide as revealed by SDS gel electrophoresis and Western blot analysis. An antiserum was produced in rabbits against the purified Coprinus endonuclease. The specificity of this antiserum was demonstrated in a dot-blot analysis and, more critically, in an immunoinhibition of endonuclease activity. The Coprinus endonuclease requires Mg2+ and/or Ca2+ as co-factors. Ca2+ is more efficient than Mg2+ while the effect of combining both co-factors is the highest. The Coprinus endonuclease has a substrate preference for single-strand and supercoiled DNA. It gives only single-strand nicks on supercoiled DNA at low enzyme concentration and limited time of incubation. At high enzyme concentration and/or long incubation time, double-strand fragmentation occurred. As is discussed, this endonuclease is believed to be involved in the early phase of meiotic recombination.
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PMID:Purification and characterization of an endonuclease from fruiting caps of basidiomycete Coprinus cinereus. 283 39


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