title: Defects in a quinol oxidase lead to loss of KatC catalase activity in Pseudomonas aeruginosa: KatC activity is temperature dependent and it requires an intact disulphide bond formation system.
abstract: Mutation or overexpression of the cyanide-insensitive terminal oxidase (CIO) of Pseudomonas aeruginosa leads to temperature-sensitivity, multiple antibiotic sensitivity, and abnormal cell division and failure to produce a temperature-inducible catalase [G.R. Tavankar, D. Mossialos, H.D. Williams, Mutation or overexpression of a terminal oxidase leads to a cell division defect and multiple antibiotic sensitivity in Pseudomonas aeruginosa, J. Biol. Chem. 278 (2003) 4524-4530]. We identify this enzyme as KatC, a newly described catalase from P. aeruginosa. Loss of KatC activity leads to temperature-dependent hydrogen peroxide sensitivity, which correlates with its temperature-inducible expression pattern. This is the first description, to our knowledge, of a temperature-inducible bacterial catalase. The transcription of katC is not affected in strains lacking or overexpressing the CIO, indicating that a post-transcriptional effect leads to loss of KatC activity. Disulphide bond formation is affected in strains lacking or overexpressing the CIO. This is shown by reduced activity of the extracellular enzymes lipase and elastase, and an altered pattern of redox states of DsbA, a key protein in disulphide bond formation in P. aeruginosa, in these strains. Moreover, a dsbA mutant had no detectable KatC activity, demonstrating that an intact disulphide bond formation system is required for KatC activity and thus explaining the loss of this catalase in the cio mutant and overexpressing strains.
authors.affiliation: Division of Biology, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ, UK.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Mossialos
authors.forename: Gholam Reza
authors.initials: GR
authors.lastname: Tavankar
authors.forename: James E A
authors.initials: JE
authors.lastname: Zlosnik
authors.forename: Huw D
authors.initials: HD
authors.lastname: Williams
mesh_terms: D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D004220:Disulfides / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000378:metabolism; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D013696:Temperature; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D004220:Disulfides; D017382:Reactive Oxygen Species; D010088:Oxidoreductases; C020094:duroquinol oxidase; D002374:Catalase; D019704:Protein Disulfide-Isomerases