Mouncey N J, Gak E, Choudhary M, Oh J, Kaplan S
Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center, Medical School, Houston, TX 77030, USA.
FEMS Microbiol Lett. 2000 Nov 15;192(2):205-10. doi: 10.1111/j.1574-6968.2000.tb09383.x.
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).
球形红细菌2.4.1(T)通过由细胞色素c氧化酶和喹啉氧化酶组成的分支呼吸链进行有氧呼吸。在此，已对来自染色体II的编码两种不同喹啉氧化酶的基因进行了表征。qoxBA基因编码一种假定的血红素-铜喹啉氧化酶，而qxtAB基因编码一种与铜绿假单胞菌的氰化物不敏感氧化酶同源的喹啉氧化酶。在野生型背景下，任一氧化酶的突变均未观察到表型。在细胞色素bc(1)复合物突变体背景中含有qxtA突变的菌株无法进行有氧生长。未发现Qox氧化酶有任何作用，在各种条件下也未表达qoxB::lacZ转录融合体。这些是首次对球形红细菌2.4.1(T)的喹啉氧化酶进行表征的分子研究。
