Identification and Characterization of a New Organic Hydroperoxide Resistance (ohr) Gene with a Novel Pattern of Oxidative Stress Regulation from Xanthomonas campestris pv. phaseoli

摘要: We have isolated a new organic hydroperoxide resistance (ohr) gene from Xanthomonas campestris pv. phaseoli. This was done by complementation of an Escherichia coli alkyl reductase mutant with hydroperoxide-hypersensitive phenotype. ohr encodes 14.5-kDa protein. Its amino acid sequence shows high homology several proteins unknown function. An subsequently constructed, and it showed increased sensitivity to both growth-inhibitory killing concentrations hydroperoxides but not either H2O2 or superoxide generators. No alterations in other oxidants stresses were observed the mutant. had interesting expression patterns response low oxidants. It highly induced hydroperoxides, weakly H2O2, at all generator. The novel regulation pattern suggests existence second hydroperoxide-inducible system that differs global peroxide regulator system, OxyR. Expression various bacteria tested conferred tert-butyl killing, this so for wild-type strains. hypersensitivity mutants could be fully complemented combination ahpC ahpF partially alone. data suggested Ohr type detoxification