Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:Q9UIJ5 (Rec)
 58,342 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A class of revertants of Bacillus subtilis mutant rec H, which completely restored the ability to transformation but without restoring the activity of ATP-dependent deoxyribonuclease, is isolated and studied. Reversions are located in the same chromosome region as the original mutation. The detection of such revertants points out the existence of more than one recombination pathway for Bac. subtilis transformation.
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PMID:[One of the classes of revertants of a rec H Bacillus subtilis mutant]. 9 71

Over 95% of the deoxyribonuclease (DNase) activity of log-phase mycelia of Neurospora crassa is expressed as single-strand (ss) specific endonucleolytic activity. This activity is associated with three nucleases (D1, D2, and D3) which after partial purification from extracts, express activity with double-strand (ds) DNA as well. All three enzymes also degrade RNA at approximately the same rates that they degrade ss-DNA. D3 has been identified as endoexonuclease, an enzyme previously shown to have endonuclease activity with ss-DNA and RNA and exonuclease activity with ds-DNA, both of which are inhibited by ATP. D3 is inhibited by ATP, is relatively resistant to p-hydroxymercuribenzoate (PHMB), and sediments with an apparent molecular weight of 75 000. D2 has the properties of the previously described mitochondrial nuclease. It is a relatively unstable Mg2+-dependent endonuclease with no appreciable strand specificity for DNA. In addition, it is not inhibited by ATP and is strongly inhibited by PHMB and by the ethylenediamine tetraacetic acid (EDTA). It also sediments with an apparent molecular weight of 75,000. The properties of D1 are quite variable from one preparation to another. Freshly isolated D1 sediments with an apparent molecular weight of 180 000. It often shows some inhibition by ATP, but is relatively resistant to both PHMB and EDTA. However, on 'ageing,' the properties of D1 gradually convert to those of D2 with concomitant decrease in molecular weight, loss of inhibition by ATP, and increase in sensitivities to PHMB and EDTA. The results indicate that D1 is very likely a second form of the mitochondrial enzyme. Evidence was obtained for the presence of protein inhibitor(s) in crude extracts which may account for the masking of the ds-DNase activities of these enzymes in extracts. Two Rec-like mutants of Neurospora (uvs-3, and nuh-4) are deficient mainly inexpressed levels of D3, the endo-exonuclease. However, the levels of inactive endo-exonuclease precursor in these two mutants are higher than in the wild type. There may, therefore, be some defect in the conversion of precursor to active enzyme in these two mutants. Another mutant, which is not sensitive to mutagens relative to the wild (nuh-3), has depressed levels of both endo-exonuclease and the mitochondrial enzyme. Nuh-3 has some defect in the conversion of D1 to D2. Proteinases probably play some role in vivo in these enzyme conversions.
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PMID:The major intracellular alkaline deoxyribonuclease activities expressed in wild-type and Rec-like mutants of Neurospora crassa. 15 96

Upon exposure to the carcinogens N-acetoxy-N-2-acetylaminofluorene and 7-bromomethyl-benz[a]anthracene, which bind covalently to DNA, ether-permeabilized (nucleotide-permeable) Escherichia coli wild-type cells responded with DNA excision repair. This repair was missing in mutants carrying defects in genes uvrA, uvrB and uvrC, whereas it was present in uvrD and several rec mutants. Enzymic activities involved were identified by measuring repair polymerization and size reduction of denatured DNA. 1. An easily measurable effect in E. coli wild-type cells was carcinogen-induced repair polymerization. When initiated by N-acetoxy-N-2-acetylaminofluorene or 7-bromomethyl-benz[a]anthracene, it depended upon an ATP-requiring step; CTP, GTP or UTP did not substitute for ATP. DNA repair synthesis was inhibited by p-chloromercuribenzoate and quinacrine. In uvrA, uvrB and uvrC mutants no carcinogen-stimulated DNA synthesis could be detected, indicating that steps involved in pyrimidine dimer excision are also involved in chemorepair. In recA, recB and recC mutant cells, repair synthesis was stimulated by the carcinogens to a normal extent. This evidence excludes the ATP-dependent recB,C deoxyribonuclease and recA gene products as playing an important role in carcinogen-induced excision repair. polA1 cells showed drastically reduced levels of rapair polymerization, indicating that DNA polymerase I is the main polymerizing enzyme. 2. As determined by DNA size reduction in alkaline sucrose gradients, the arylalkylating carcinogens caused endonucleolytic cleavage of endogenous DNA in wild-type cells. This incision step was most effectively performed in the presence of ATP; UTP, CTP and GTP were only slightly effective. Incision was inhibited by p-chloromercuribenzoate and quinacrine. When exposed to the arylalkylating carcinogens, uvrA, uvrB and uvrC mutant cells did not perform the incision step in the presence of ATP, suggesting the involvement of the respective gene products in the initiation of chemorepair.
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PMID:Carcinogen-induced DNA repair in nucleotide-permeable Escherichia coli cells. Analysis of DNA repair induced by the carcinogens N-acetoxy-N-2-acetylaminofluorene and 7-bromomethyl-benz(a)anthracene. 76 31

Four out of more than 8,200 Staphylococcus aureus strains isolated in Japan between 1961 and 1980 were constitutively resistant to a variety of macrolide antibiotics except tylosin and rokitamycin, but susceptible to lincosamide and streptogramin type B antibiotics (PM). The data obtained by agarose gel electrophoresis, CsCl-ethidium bromide density gradient analysis, diagnosis with ATP-dependent deoxyribonuclease, and a test transducing into a rec- mutant with phage 80L2 propagated on PM-resistant S. aureus all suggested that the determinant for the PM-resistance is located in chromosome.
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PMID:Localization of a determinant mediating partial macrolide resistance in Staphylococcus aureus. 212 34

Protoplast fusion between the Rec- mutant RN981 (L. Wyman, R. V. Goering, and R. P. Novick, Genetics 76:681-702, 1974) of Staphylococcus aureus NCTC 8325 and a Rec+ NCTC 8325 derivative yielded Rec+ recombinants that exhibited the increased sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine characteristic of RN981. Transformation analyses identified a specific mutation, designated ngr-374, that was responsible not only for N-methyl-N'-nitro-N-nitrosoguanidine sensitivity, but also sensitivity to methyl methanesulfonate, ethyl methanesulfonate, nitrous acid, and UV irradiation. However, ngr-374-carrying recombinants showed no significant increase in their sensitivity to mitomycin C or 4-nitroquinoline 1-oxide and were unaffected in recombination proficiency. In vitro assays showed that ngr-374-carrying strains had lower apurinic/apyrimidinic endonuclease activities than the wild type. The chromosomal locus occupied by ngr-374 was shown to exist in the gene order omega(Chr::Tn551)40-ngr-374-thrB106.
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PMID:Characterization and genetic mapping of a mutation affecting apurinic endonuclease activity in Staphylococcus aureus. 243 Sep 40

A RecA/Rad51 homologue from Pyrococcus kodakaraensis KOD1 (Pk-REC) is the smallest protein among various RecA/Rad51 homologues. Nevertheless, Pk-Rec is a super multifunctional protein and shows a deoxyribonuclease activity. This deoxyribonuclease activity was inhibited by 3 mM or more ATP, suggesting that the catalytic centers of the ATPase and deoxyribonuclease activities are overlapped. To examine whether these two enzymatic activities share the same active site, a number of site-directed mutations were introduced into Pk-REC and the ATPase and deoxyribonuclease activities of the mutant proteins were determined. The mutant enzyme in which double mutations Lys-33 to Ala and Thr-34 to Ala were introduced, fully lost both of these activities, indicating that Lys-33 and/or Thr-34 are important for both ATPase and deoxyribonuclease activities. The mutation of Asp-112 to Ala slightly and almost equally reduced both ATPase and deoxyribonuclease activities. In addition, the mutation of Glu-54 to Gln did not seriously affect the ATPase, deoxyribonuclease, and UV tolerant activities. These results strongly suggest that the active sites of the ATPase and deoxyribonuclease activities of Pk-REC are common. It is noted that unlike Glu-96 in Escherichia coli RecA, which has been proposed to be a catalytic residue for the ATPase activity, the corresponding residual Glu-54 in Pk-REC is not involved in the catalytic function of the protein.
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PMID:A unique DNase activity shares the active site with ATPase activity of the RecA/Rad51 homologue (Pk-REC) from a hyperthermophilic archaeon. 1006 83

The viscosity of the mucus, its DNA concentration and the size range of the DNA were determined on tracheobronchial samples from 11 horses with lower airway diseases before and after incubation with recombinant human deoxyribonuclease (rhDNase). The horses were divided into two groups on the basis of the cytology of the samples: group A (five horses) with more than 60 per cent neutrophils and group B (six horses) with fewer than 50 per cent neutrophils. The mean mucus viscosity and DNA concentration in the preincubation samples were significantly higher in group A than in group B, and there was a correlation between DNA concentration and mucus viscosity in the preincubation samples from group A. Incubation with rhDNase significantly reduced the viscosity of the samples only in group A.
Vet Rec 2000 Nov 25
PMID:In vitro mucolytic activity of recombinant human deoxyribonuclease on equine tracheobronchial mucus. 1112 76