Linked Life Data

21570366

Source:http://linkedlifedata.com/resource/pubmed/id/21570366

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2011-6-6
pubmed:abstractText
The ada operon of Mycobacterium tuberculosis, which encodes a composite protein of AdaA and AlkA and a separate AdaB/Ogt protein, was characterized. M. tuberculosis treated with N-methyl-N'-nitro-N-nitrosoguanidine induced transcription of the adaA-alkA and adaB genes, suggesting that M. tuberculosis mount an inducible response to methylating agents. Survival assays of the methyltransferase defective Escherichia coli mutant KT233 (ada ogt), showed that expression of the adaB gene rescued the alkylation sensitivity. Further, adaB but not adaA-alkA complemented the hypermutator phenotype of KT233. Purified AdaA-AlkA and AdaB possessed methyltransferase activity. These data suggested that AdaB counteract the cytotoxic and mutagenic effect of O(6)-methylguanine, while AdaA-AlkA most likely transfers methyl groups from innocuous methylphosphotriesters. AdaA-AlkA did not possess alkylbase DNA glycosylase activity nor rescue the alkylation sensitivity of the E. coli mutant BK2118 (tag alkA). We propose that AdaA-AlkA is a positive regulator of the adaptive response in M. tuberculosis. It thus appears that the ada operon of M. tuberculosis suppresses the mutagenic effect of alkylation but not the cytotoxic effect of lesions such as 3-methylpurines. Collectively, these data indicate that M. tuberculosis hypermutator strains with defective adaptive response genes might sustain robustness to cytotoxic alkylation DNA damage and confer a selective advantage contributing to host adaptation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1568-7856
pubmed:author
pubmed:copyrightInfo
Copyright © 2011 Elsevier B.V. All rights reserved.
pubmed:issnType
Electronic
pubmed:day
10
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
595-602
pubmed:meshHeading
pubmed:year
2011
pubmed:articleTitle
The ada operon of Mycobacterium tuberculosis encodes two DNA methyltransferases for inducible repair of DNA alkylation damage.
pubmed:affiliation
Department of Microbiology, Oslo University Hospital, Rikshospitalet, PO Box 4950 Nydalen, NO-0424 Oslo, Norway.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't