title: Exonuclease III and the catalase hydroperoxidase II in Escherichia coli are both regulated by the katF gene product.
abstract: The levels of both exonuclease III (exo III, product of xthA) and hydroperoxidase II (HP-II, product of katE) activity in Escherichia coli were influenced by a functional katF gene. The katF gene product is also necessary for synthesis of HP-II. Mutations in either katF or xthA, but not katE, result in sensitivity to H2O2 and near-UV (300-400 nm) radiation. Exo III, encoded by the xthA locus, recognizes and removes nucleoside 5'-monophosphates near apurinic and apyrimidinic sites in damaged DNA. Extracts of katF mutant strains had little detectable exo III activity. When a katF+ plasmid was introduced into the katF mutant, exo III activity exceeded wild-type levels. We propose that the katF gene is a trans-acting positive regulator of exo III and HP-II enzymes, both of which are involved in cellular recovery from oxidative damage.
authors.affiliation: Division of Biological Sciences, University of Missouri, Columbia 65211.
authors.forename: B D
authors.initials: BD
authors.lastname: Sak
authors.forename: A
authors.initials: A
authors.lastname: Eisenstark
authors.forename: D
authors.initials: D
authors.lastname: Touati
mesh_terms: D001080:Apurinic Acid / Q000378:metabolism; D004249:DNA Damage; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000528:radiation effects; D005090:Exodeoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005809:Genes, Regulator; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009154:Mutation; D009195:Peroxidase / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D011119:Polynucleotides / Q000378:metabolism; D014169:Transformation, Bacterial; D014466:Ultraviolet Rays
chemical_list: D011119:Polynucleotides; C001790:apyrimidinic acid; D001080:Apurinic Acid; D006861:Hydrogen Peroxide; D009195:Peroxidase; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III