title: Molecular characterization of katA from Campylobacter jejuni and generation of a catalase-deficient mutant of Campylobacter coli by interspecific allelic exchange.
abstract: A gene encoding catalase (hydrogen-peroxide:hydrogen-peroxide oxidoreductase; EC 1.11.1.6) from Campylobacter jejuni was cloned by functional complementation of a catalase-deficient mutant of Escherichia coli. The catalase structural gene, designated katA, was assigned by subcloning and its nucleotide sequence determined. The deduced protein product of 508 amino acids, which had a calculated molecular mass of 58,346 Da, was found to be structurally and enzymically similar to hydrogen-peroxidases from other bacterial species. The region of DNA containing the structural catalase gene was disrupted by insertion of a tetracycline-resistance marker and the modified sequence then introduced into a strain of Campylobacter coli via natural transformation. Genetic and enzymic analyses of a tetracycline-resistant C. coli transformant confirmed that catalase-deficient mutants had arisen via interspecific allelic exchange. Compared to the isogenic parental strain the mutant was more sensitive to killing by H2O2.
authors.affiliation: Institute of Food Research, Reading Laboratory,Earley Gate, Whiteknights Road, Reading, RG6 2EF,UK.
authors.forename: Kathleen A
authors.initials: KA
authors.lastname: Grant
authors.affiliation: Institute of Food Research, Reading Laboratory,Earley Gate, Whiteknights Road, Reading, RG6 2EF,UK.
authors.forename: Simon F
authors.initials: SF
authors.lastname: Park
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D001483:Base Sequence; D017000:Campylobacter coli / Q000235:genetics*; D016123:Campylobacter jejuni / Q000187:drug effects / Q000235:genetics*; D002374:Catalase / Q000737:chemistry* / Q000235:genetics; D004352:Drug Resistance, Microbial / Q000235:genetics; D004790:Enzyme Induction; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008969:Molecular Sequence Data; D008970:Molecular Weight; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D006861:Hydrogen Peroxide; D002374:Catalase