Quinol oxidase subunit III (IPR014246)

Short name: QoxC

Overlapping homologous superfamilies

Family relationships


This entry encodes subunit III of the aa3-type quinone oxidase (QoxC), a multi-chain transmembrane protein located in the cell membrane and one of several aerobic bacterial terminal oxidases [PMID: 7575098]. This complex couples oxidation of reduced quinones to the reduction of molecular oxygen to water, and the pumping of protons to form the proton gradient utilised for ATP production. aa3-type oxidases contain two haem A cofactors as well as copper atoms at the active site.

Quinone oxidases feature four subunits in contrast to the 13 subunit bovine cytochrome c oxidase (CcO). Subunits I, II and III of ubiquinol oxidase are homologous to the corresponding subunits in bovine CcO [PMID: 8392948, PMID: 8253216]. Although not required for catalytic activity, subunit III appears to be involved in assembly of the multimer complex [PMID: 11017202].

GO terms

Biological Process

GO:0042773 ATP synthesis coupled electron transport

Molecular Function

GO:0015002 heme-copper terminal oxidase activity

Cellular Component

GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.