title: Respiratory pathways of Rhodobacter sphaeroides 2.4.1(T): identification and characterization of genes encoding quinol oxidases.
abstract: Rhodobacter sphaeroides 2.4.1(T) respires aerobically via a branched respiratory chain consisting of both cytochrome c oxidases and quinol oxidases. Here, genes from chromosome II encoding two distinct quinol oxidases have been characterized. The qoxBA genes encode a putative heme-copper quinol oxidase, whereas the qxtAB genes encode a quinol oxidase homologous to the cyanide-insensitive oxidase of Pseudomonas aeruginosa. No phenotype was observed for mutations in either oxidase in the wild-type background. A strain containing a qxtA mutation in a cytochrome bc(1) complex mutant background was unable to grow aerobically. No role was found for the Qox oxidase, nor was a qoxB::lacZ transcriptional fusion expressed under a variety of conditions. These are the first molecular studies to characterize the quinol oxidases of R. sphaeroides 2.4.1(T).
authors.affiliation: Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Medical School, Houston, TX 77030, USA.
authors.forename: N J
authors.initials: NJ
authors.lastname: Mouncey
authors.forename: E
authors.initials: E
authors.lastname: Gak
authors.forename: M
authors.initials: M
authors.lastname: Choudhary
authors.forename: J
authors.initials: J
authors.lastname: Oh
authors.forename: S
authors.initials: S
authors.lastname: Kaplan
mesh_terms: D000332:Aerobiosis; D003001:Cloning, Molecular; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D009876:Operon; D010088:Oxidoreductases / Q000235:genetics*; D012242:Rhodobacter sphaeroides / Q000201:enzymology / Q000502:physiology*
chemical_list: D010088:Oxidoreductases; C020094:duroquinol oxidase