InterPro domain: IPR002124

Cytochrome c oxidase ( 1.9.3.1 ) is an oligomeric enzymatic complex which is a component of the respiratory chain complex and is involved in the transfer of electrons from cytochrome c to oxygen [ 1 ]. In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane.

In eukaryotes, in addition to the three large subunits, I, II and III, that form the catalytic centre of the enzyme complex, there are a variable number of small polypeptidic subunits. One of these subunits, which is known as Vb in mammals, V in Dictyostelium discoideum (Slime mold) and IV in yeast, binds a zinc atom. The sequence of subunit Vb is well conserved and includes three conserved cysteines that coordinate the zinc ion [ 2 , 3 ]. Two of these cysteines are clustered in the C-terminal section of the subunit.

1. Structure of cytochrome c oxidase. Biochim. Biophys. Acta 726, 135-48
2. The most conserved nuclear-encoded polypeptide of cytochrome c oxidase is the putative zinc-binding subunit: primary structure of subunit V from the slime mold Dictyostelium discoideum. Biochim. Biophys. Acta 1129, 100-4
3. The whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A. Science 272, 1136-44