HMM Summary Page: TIGR01432

Functioncytochrome aa3 quinol oxidase, subunit II
Gene SymbolqoxA
Trusted Cutoff240.95
Domain Trusted Cutoff240.95
Noise Cutoff204.55
Domain Noise Cutoff204.55
Isology Typeequivalog
EC Number1.10.3.-
HMM Length227
Mainrole CategoryEnergy metabolism
Subrole CategoryElectron transport
Gene Ontology TermGO:0009055: electron carrier activity molecular_function
GO:0015002: heme-copper terminal oxidase activity molecular_function
GO:0015078: hydrogen ion transmembrane transporter activity molecular_function
GO:0015990: electron transport coupled proton transport biological_process
GO:0016021: integral to membrane cellular_component
GO:0016682: oxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor molecular_function
GO:0055114: oxidation-reduction process biological_process
AuthorSelengut J
Entry DateFeb 4 2002 10:20AM
Last ModifiedFeb 14 2011 3:27PM
CommentThis enzyme catalyzes the oxidation of quinol with the concomitant reduction of molecular oxygen to water. This acts as the terminal electron acceptor in the respiratory chain. This subunit contains two transmembrane helices and a large external domain responsible for the binding and oxidation of quinol. QuoX is (presently) only found in gram positive bacteria of the Bacillus/Staphylococcus group. Like CyoA, the ubiquinol oxidase found in proteobacteria, the residues responsible for the ligation of Cu(a) and cytochrome c (found in the related cyt. c oxidases) are absent. Unlike CyoA, QoxA is in complex with a subunit I which contains cytochromes a similar to the cyt. c oxidases (as opposed to cytochromes b).
ReferencesRN [1] RM 1316894 RT Molecular cloning, sequencing, and physiological characterization of the qox operon from Bacillus subtilis encoding the aa3-600 quinol oxidase RA Santana M, Kunst F, Hullo MF, Rapoport G, Danchin A, Glaser P RL J Biol Chem 1992 May 25;267(15):10225-31 DR EXPERIMENTAL; SP|P34957; Bacillus subtilis caa3-600 DR PROSITE; PR02790; COX2_TM; partial hit; score = 2.55 DR OUTGROUP; EGAD 20044; Escherichia coli CyoA
Genome PropertyGenProp0620: cytochrome (quinone) oxidase, aa3 type, QoxABCD (HMM)