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)

The N complementation group of adenovirus (Ad) serotype 5 mutants, which are temperature sensitive for viral DNA synthesis in vivo, has been used to study a 140,000-dalton DNA polymerase (Pol) that copurified with the 80,000-dalton terminal protein precursor (pTP). Extracts prepared from HeLa cells infected with the N group mutant H5ts149 at nonpermissive temperature were unable to synthesize viral DNA. The defect in these extracts was specifically reversed by addition of the Pol purified from wild-type Ad-infected cytosol. Addition of the pTP, free of the Pol, did not restore replicative activity to H5ts149 extracts. The reactions studied depend on the presence of the DNA template and include the initiation reaction (the covalent attachment of dCMP to the pTP) and the selective replication of Ad DNA restriction endonuclease fragments containing the origin sequences. Glycerol gradient sedimentation showed that a replicative activity representing the pTP-Pol complex was greatly reduced in H5ts149 extracts as compared with wild-type extracts, suggesting some alteration in the mutant. A pool of pTP free of Pol was detected on these gradients in extracts from both wild-type and H5ts149-infected cells. In addition, the initiation and elongation of Ad DNA catalyzed by H5ts149 extracts prepared from cells grown at permissive temperatures was more labile to urea inactivation than extracts prepared from cells infected with wild-type virus. These results, considered together with the mapping of the H5ts149 mutation within an open reading frame approximately large enough to code for the 140,000-dalton DNA polymerase [Gingeras, T. R., Sciaky, D., Gelinas, R. E., Bing-Dong, J., Yen, C. E., Kelly, M. M., Bullock, P. A., Parsons, B. L., O'Neill, K. E. & Roberts, R. J. (1982) J. Biol. Chem. 257, 13475-13491; Alestrom, P., Akusjarui, G., Pettersson, M. & Pettersson, U. (1982) J. Biol. Chem. 257, 13492-13498], suggest that the Pol is a virally encoded protein, as is the pTP.
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PMID:Evidence for an altered adenovirus DNA polymerase in cells infected with the mutant H5ts149. 657 22

DNase VIII is an exonuclease purified from human placenta trophoblast nuclei. The enzyme has a pH optimum of 9.5 and requires a divalent cation. It is inhibited by salt and stimulated by Triton X-100. Glycerol gradient analysis of the activity indicates a sedimentation coefficient of 2.8 S (31,000 daltons if globular). This enzyme initiates hydrolysis from 5'-phosphorylated termini of single-stranded DNA and acts at internal phosphodiester bonds liberating 5'-phosphorylated oligonucleotides. It degrades polynucleotides of repeating base sequence as well as single-stranded DNA, yielding oligonucleotides of even number, in which the main reaction products are dinucleotides. The activity on denatured DNA is not inhibited by the presence of ultraviolet-induced photoproducts. DNase VIII can also initiate hydrolysis at those distorted termini produced by the action of Micrococcus luteus dimer specific endonuclease on duplex DNA, which contains cyclobutane dimers.
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PMID:Purification and characterization of DNase VIII. A 5'-3' directed exonuclease from human placental nuclei. 682 22

The genomes of three main biovars of Yersinia pestis were subjected to restriction fragment length polymorphism analysis using I-CeuI endonuclease. I-CeuI which is encoded by a mobile intron in Chlamydomonas engamenans recognizes a 25-bp site in the ribosomal RNA rrl gene and cuts DNA of most representatives of Enterobacteriaceae into seven fragments corresponding to the presence of seven rrn-operons. Glycerol-positive Y. pestis strains (biovars antiqua and mediaevalis) contain seven ribosomal operons which can be recognized by I-CeuI endonuclease. However, glycerol-negative strains of Y. pestis biovar orientalis expose only six restriction sites for I-CeuI. The restriction fragment length polymorphism patterns obtained with I-CeuI make it possible to distinguish between three biovars of Y. pestis. Use of another rare cutting restriction enzyme, Bln/I, permits differentiation between pigment-adsorbing and avirulent non-pigment-adsorbing Y. pestis. Still, due to homologous recombination between the two copies of IS 100 insertion sequence bracketing the pgm-locus, the mechanism of deletions in the pgm-locus seems to be confined only to strains of biovars antiqua and mediaevalis, and can be different in Y. pestis strains of biovar orientalis. The I-CeuI restriction patterns of two Yersinia strains isolated within a ten-year period in the port of St. Petersburg and originally identified as Y. pseudotuberculosis 01 turned out to be related to typical representatives of Y. pestis biovar antiqua. These strains could be exported from the same source or circulate among Rattus norvegicus population of the port as non-pigment-adsorbing avirulent immunogenic clone.
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PMID:The established Yersinia pestis biovars are characterized by typical patterns of I-CeuI restriction fragment length polymorphism. 747 35