title: Need for cytochrome bc1 complex for dissimilatory nitrite reduction of Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa strains deficient in the genes for cytochrome c1, a subunit of the cytochrome bc1 complex, or the tetraheme membrane protein NapC, which is similar to NirT of Pseudomonas stutzeri, were constructed and their growth was investigated. The cytochrome c1 mutant could not grow under anaerobic conditions with nitrite as an electron acceptor and did not reduce nitrite in spite of its producing active nitrite reductase. NirM (cytochrome c551) and azurin, which are the direct electron donors for nitrite reductase, were reduced by succinate in the presence of the membrane fraction from the wild-type strain as a mediator but not in the presence of that from the cytochrome c1 mutant. These results indicated that cytochrome bc1 complex was necessary for electron transfer from the membrane quinone pool to nitrite reductase. The NapC mutant grew anaerobically at the expense of nitrite, indicating that NapC was not necessary for nitrite reduction.
authors.affiliation: Department of Biotechnology, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Hasegawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Arai
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D001400:Azurin / Q000378:metabolism; D015153:Blotting, Western; D004579:Electron Transport; D014450:Electron Transport Complex III / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008566:Membranes / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009572:Nitrite Reductases / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D011401:Promoter Regions, Genetic / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000235:genetics; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D008565:Membrane Proteins; D009573:Nitrites; D001400:Azurin; D009572:Nitrite Reductases; D014450:Electron Transport Complex III