ccoNOQP gene cluster codes for a cb-type cytochrome oxidase that functions in aerobic respiration of Rhodobacter capsulatus

• Published in: Molecular microbiology Vol. 14; no. 4; pp. 705 - 716
• Main Authors: Thony-Meyer, L, Beck, C, Preisig, O, Hennecke, H
• Format: Journal Article
• Language: English
• Published: England 01.11.1994
• Subjects: Aerobiosis; Amino Acid Sequence; amino acid sequences; Base Sequence; Bradyrhizobium japonicum; Chromosome Mapping; cloning; Cloning, Molecular; DNA; DNA Primers - genetics; DNA, Bacterial - genetics; Electron Transport Complex IV - classification; Electron Transport Complex IV - genetics; Electron Transport Complex IV - metabolism; genbank/z21854; Genes, Bacterial; genetic code; Molecular Sequence Data; Multigene Family; Mutation; nitrogen fixation; Nitrogen Fixation - genetics; nitrogen-fixing bacteria; oxidoreductases; Pseudomonas aeruginosa - enzymology; Pseudomonas aeruginosa - genetics; respiration; Rhizobiaceae - enzymology; Rhizobiaceae - genetics; Rhizobium - enzymology; Rhizobium - genetics; Rhodobacter capsulatus - enzymology; Rhodobacter capsulatus - genetics; Sequence Homology, Amino Acid; Species Specificity; structural genes
• ISSN: 0950-382X; 1365-2958
• DOI: 10.1111/j.1365-2958.1994.tb01308.x

The genes for a new type of a haem-copper cytochrome oxidase were cloned from Rhodobacter capsulatus strain 37b4 using the Bradyrhizobium japonicum fixNOQP gene region as a hybridizing probe. Four genes probably organized in an operon (ccoNOQp), were identified; their products share extensive amino acid sequence similarity with the FixN, O, Q and P proteins that have recently been shown to be the subunits of a cb-type oxidase. CcoN is a b-type cytochrome CcoO and CcoP are membrane-bound mono- and dihaem c-type cytochromes and ccoQ is a small membrane protein of unknown function. Genes for a similar oxidase are also present in other non-rhizobial bacterial species such as Azotobacter vinelandii, Agrobacterium tumefaciens and Pseudomonas aeruginosa, as revealed by polymerase chain reaction analysis. A ccoN mutant was constructed whose phenotype in combination with the structural information on the gene products provides evidence that the CcoNOQP oxidase is a cytochrome c oxidase of the cb type which supports aerobic respiration in R. capsulatus and which is probably identical to the cbb3-type oxidase that was recently purified from a different strain of the same species. Mutant analysis also showed that this oxidase has no influence on photosynthetic growth and nitrogen-fixation activity.