Heme-copper terminal oxidase using both cytochrome c and ubiquinol as electron donors.

ABSTRACT: The cytochrome c oxidase Cox2 has been purified from native membranes of the hyperthermophilic eubacterium Aquifex aeolicus. It is a cytochrome ba(3) oxidase belonging to the family B of the heme-copper containing terminal oxidases. It consists of three subunits, subunit I (CoxA2, 63.9 kDa), subunit II (CoxB2, 16.8 kDa), and an additional subunit IIa of 5.2 kDa. Surprisingly it is able to oxidize both reduced cytochrome c and ubiquinol in a cyanide sensitive manner. Cox2 is part of a respiratory chain supercomplex. This supercomplex contains the fully assembled cytochrome bc(1) complex and Cox2. Although direct ubiquinol oxidation by Cox2 conserves less energy than ubiquinol oxidation by the cytochrome bc(1) complex followed by cytochrome c oxidation by a cytochrome c oxidase, ubiquinol ox

SUBMITTER: Gao Y 

PROVIDER: S-EPMC3295305 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature