Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0519030 (Klebsiella)
 21,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An efficient adaptive response to alkylation damage was observed in several enterobacterial species, including Klebsiella aerogenes, Shigella sonnei, Shigella boydii, Escherichia alkalescens, Escherichia hermanii, and Escherichia fergusonii. Increased O6-methylguanine-DNA and methylphosphotriester-DNA methyltransferase activities correlated with the induction of a 39-kDa protein recognized by monoclonal antibodies raised against the Escherichia coli Ada protein. Induced methyltransferase activities were similarly observed in Aerobacter aerogenes and Citrobacter intermedius, although no antigenically cross-reacting material was present. Weak induction of a 39-kDa protein immunologically related to the E. coli Ada protein occurred in Salmonella typhimurium. This protein encoded by the cloned S. typhimurium ada gene was shown to be an active methyltransferase which repaired O6-methylguanine and methylphosphotriesters in DNA as efficiently as did the E. coli Ada protein. However, the mehtyltransferase activity of the weakly induced 39-kDa protein in S. typhimurium was not detected, apparently because it was self-methylated and thus inactivated during the adaptive N-methyl-N-nitro-N-nitrosoguanidine pretreatment. In contrast, the E. coli ada gene on a low-copy-number plasmid was efficiently induced in S. typhimurium, and high methyltransferase activities were observed. We concluded that the inefficient induction of the adaptive response in S. typhimurium results from weak transcriptional activation of its ada gene by the self-methylated protein.
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PMID:A weak adaptive response to alkylation damage in Salmonella typhimurium. 205 Jun 26

CB1954 is an anti-cancer prodrug that can be reduced at either of two nitro groups to form cytotoxic metabolites. We describe here two efficient and previously uncharacterized nitroreductases, YfkO from Bacillus subtilis which reduces CB1954 exclusively at the 4-NO(2) position, and NfsA from Klebsiella pneumoniae which preferentially reduces the 2-NO(2) group. Utilizing these novel enzymes, together with three previously characterized nitroreductases, we demonstrate that the Escherichia coli SOS-chromotest assay can differentially detect the 4-nitro versus 2-nitro reduction products of CB1954 following deletion of the nucleotide excision repair gene uvrB, but not mismatch repair (mutS) or methyltransferase (ada/ogt) genes. These findings may hold significance for identification and selection of nitroreductases for CB1954-mediated gene therapy, particularly when targeting tumors that are deficient in nucleotide excision repair. Moreover, we demonstrate that comparative SOS chromotest analysis in wild type and uvrB mutant strains can be used to determine whether or not nucleotide excision repair plays a significant role in processing DNA damage resulting from activation of different nitroaromatic prodrugs.
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PMID:uvrB gene deletion enhances SOS chromotest sensitivity for nitroreductases that preferentially generate the 4-hydroxylamine metabolite of the anti-cancer prodrug CB1954. 2072 18