Respiratory pathways of Rhodobacter sphaeroides 2.4.1(T): identification and characterization of genes encoding quinol oxidases.
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).
Mouncey
N J
NJ
Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Medical School, Houston, TX 77030, USA.
Gak
E
E
Choudhary
M
M
Oh
J
J
Kaplan
S
S
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*
D010088:Oxidoreductases; C020094:duroquinol oxidase