| Cytochrome c oxidase subunit II, transmembrane domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Bacterial cytochrome c oxidase complex. Subunit II indicated by blue. | |||||||||
| Identifiers | |||||||||
| Symbol | COX2_TM | ||||||||
| Pfam | PF02790 | ||||||||
| InterPro | IPR011759 | ||||||||
| PROSITE | PDOC00075 | ||||||||
| SCOP | 1occ | ||||||||
| TCDB | 3.D.4 | ||||||||
| OPM family | 4 | ||||||||
| OPM protein | 1v55 | ||||||||
|
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| Cytochrome C oxidase subunit II, periplasmic domain | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| Symbol | COX2 | ||||||||
| Pfam | PF00116 | ||||||||
| InterPro | IPR002429 | ||||||||
| PROSITE | PDOC00075 | ||||||||
| SCOP | 1occ | ||||||||
| TCDB | 3.D.4 | ||||||||
| OPM family | 4 | ||||||||
| OPM protein | 1v55 | ||||||||
|
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Cytochrome c oxidase subunit II, abbreviated CoxII, is the second subunit of cytochrome c oxidase.
Cytochrome c oxidase (EC 1.9.3.1)[1][2] is an oligomeric enzymatic complex which is a component of the respiratory chain and is involved in the transfer of electrons from cytochrome c to oxygen. In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane. The enzyme complex consists of 3-4 subunits (prokaryotes) to up to 13 polypeptides (mammals). In Leigh's disease, there may be an abnormality or deficiency of cytochrome oxidase.
Subunit 2 (CO II) transfers the electrons from cytochrome c to the catalytic subunit 1. It contains two adjacent transmembrane regions in its N-terminus and the major part of the protein is exposed to the periplasmic or to the mitochondrial intermembrane space, respectively. CO II provides the substrate-binding site and contains a copper centre called Cu(A) (see IPR001505), probably the primary acceptor in cytochrome c oxidase. An exception is the corresponding subunit of the cbb3-type oxidase which lacks the copper A redox-centre. Several bacterial CO II have a C-terminal extension that contains a covalently bound haem c.
The N-terminal domain of cytochrome C oxidase contains two transmembrane alpha-helices.