Linked Life Data

18667555

Source:http://linkedlifedata.com/resource/pubmed/id/18667555

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
Pt 8
pubmed:dateCreated
2008-7-31
pubmed:abstractText
The microaerophilic food-borne pathogen Campylobacter jejuni is exposed to highly variable oxygen concentrations during its life cycle and employs a variety of protection mechanisms to resist oxidative stress. However, not all of the enzymes that mediate such protection have yet been identified. Two genes in strain NCTC 11168, Cj0637c and Cj1112c, are predicted to encode unrelated methionine sulphoxide reductases, which may repair oxidized methionine residues in proteins and thus contribute to oxidative stress defence. Cj0637 and Cj1112 were overexpressed, purified and shown by a coupled thioredoxin-thioredoxin reductase-NADPH assay to catalyse the stereospecific reduction of the S and R diastereoisomers, respectively, of the model compound methyl p-tolyl sulphoxide. Cj0637 is thus identified as MsrA and Cj1112 as MsrB. The contribution of these enzymes to oxidative and nitrosative stress resistance in C. jejuni was assessed by phenotypic analysis of a set of isogenic msrA, msrB and msrA/B insertion mutants. As RT-PCR data suggested a polar effect on Cj1111c in the msrB mutant, an msrB/msrB(+) merodiploid complementation strain was also constructed. The msrA/B strain was severely growth inhibited under standard microaerobic conditions, whereas the msrA and msrB strains grew normally. Agar plate disc diffusion assays showed that all mutants displayed increased sensitivity to hydrogen peroxide, organic peroxide, superoxide, and nitrosative and disulphide stress, but quantitative cell viability assays showed that the msrA/B double mutant was markedly more sensitive to both oxidative and nitrosative stress. All of the stress-sensitivity phenotypes observed for the msrB mutant were restored to wild-type in the msrB/msrB(+) merodiploid. It is concluded that MsrA and MsrB make a significant contribution to the protection of C. jejuni against oxidative and nitrosative stress.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1350-0872
pubmed:author
pubmed:issnType
Print
pubmed:volume
154
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2219-30
pubmed:dateRevised
2010-11-18
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Contribution of the stereospecific methionine sulphoxide reductases MsrA and MsrB to oxidative and nitrosative stress resistance in the food-borne pathogen Campylobacter jejuni.
pubmed:affiliation
Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield, UK.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't