O21403 · COX3_STRCA
- ProteinCytochrome c oxidase subunit 3
- GeneMT-CO3
- StatusUniProtKB reviewed (Swiss-Prot)
- Amino acids261 (go to sequence)
- Protein existenceInferred from homology
- Annotation score3/5
Function
function
Component of the cytochrome c oxidase, the last enzyme in the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over the inner membrane that drives transmembrane transport and the ATP synthase. Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Electrons originating from reduced cytochrome c in the intermembrane space (IMS) are transferred via the dinuclear copper A center (CU(A)) of subunit 2 and heme A of subunit 1 to the active site in subunit 1, a binuclear center (BNC) formed by heme A3 and copper B (CU(B)). The BNC reduces molecular oxygen to 2 water molecules using 4 electrons from cytochrome c in the IMS and 4 protons from the mitochondrial matrix.
Catalytic activity
- 4 Fe(II)-[cytochrome c] + 8 H+(in) + O2 = 4 Fe(III)-[cytochrome c] + 4 H+(out) + 2 H2OThis reaction proceeds in the forward direction.
4 RHEA-COMP:10350 + 8 H+ (in)CHEBI:15378+ CHEBI:15379 = 4 RHEA-COMP:14399 + 4 H+ (out)CHEBI:15378+ 2 CHEBI:15377
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | mitochondrial inner membrane | |
Cellular Component | respiratory chain complex IV | |
Molecular Function | cytochrome-c oxidase activity | |
Biological Process | aerobic electron transport chain |
Keywords
- Molecular function
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameCytochrome c oxidase subunit 3
- EC number
- Alternative names
Gene names
Encoded on
- Mitochondrion
Organism names
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Archelosauria > Archosauria > Dinosauria > Saurischia > Theropoda > Coelurosauria > Aves > Palaeognathae > Struthioniformes > Struthionidae > Struthio
Accessions
- Primary accessionO21403
- Secondary accessions
Subcellular Location
UniProt Annotation
GO Annotation
Mitochondrion inner membrane ; Multi-pass membrane protein
Features
Showing features for topological domain, transmembrane.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Topological domain | 1-15 | Mitochondrial matrix | ||||
Sequence: MAHQAHSYHMVDPSP | ||||||
Transmembrane | 16-34 | Helical; Name=I | ||||
Sequence: WPIFGATAALLTTSGLIMW | ||||||
Topological domain | 35-40 | Mitochondrial intermembrane | ||||
Sequence: FHYNSL | ||||||
Transmembrane | 41-66 | Helical; Name=II | ||||
Sequence: YLLTLGLLSMFLVMIQWWRDIVREST | ||||||
Topological domain | 67-72 | Mitochondrial matrix | ||||
Sequence: FQGHHT | ||||||
Transmembrane | 73-105 | Helical; Name=III | ||||
Sequence: PTVQKGLRYGMILFITSEAFFFLGFFWAFFHSS | ||||||
Topological domain | 106-128 | Mitochondrial intermembrane | ||||
Sequence: LAPTPELGAQWPPTGINPLNPLE | ||||||
Transmembrane | 129-152 | Helical; Name=IV | ||||
Sequence: VPLLNTAILLASGVTVTWAHHSIT | ||||||
Topological domain | 153-155 | Mitochondrial matrix | ||||
Sequence: ESN | ||||||
Transmembrane | 156-183 | Helical; Name=V | ||||
Sequence: RKQAIHALSLTIILGFYFTALQAMEYHE | ||||||
Topological domain | 184-190 | Mitochondrial intermembrane | ||||
Sequence: ASFSIAD | ||||||
Transmembrane | 191-223 | Helical; Name=VI | ||||
Sequence: GVYGSTFFVATGFHGLHVIIGSSFLTVCLLRLI | ||||||
Topological domain | 224-232 | Mitochondrial matrix | ||||
Sequence: KFHFTTNHH | ||||||
Transmembrane | 233-256 | Helical; Name=VII | ||||
Sequence: FGFEAAAWYWHFVDVIWLFLYMSI | ||||||
Topological domain | 257-261 | Mitochondrial intermembrane | ||||
Sequence: YWWGS |
Keywords
- Cellular component
PTM/Processing
Features
Showing features for chain.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Chain | PRO_0000183857 | 1-261 | Cytochrome c oxidase subunit 3 | |||
Sequence: MAHQAHSYHMVDPSPWPIFGATAALLTTSGLIMWFHYNSLYLLTLGLLSMFLVMIQWWRDIVRESTFQGHHTPTVQKGLRYGMILFITSEAFFFLGFFWAFFHSSLAPTPELGAQWPPTGINPLNPLEVPLLNTAILLASGVTVTWAHHSITESNRKQAIHALSLTIILGFYFTALQAMEYHEASFSIADGVYGSTFFVATGFHGLHVIIGSSFLTVCLLRLIKFHFTTNHHFGFEAAAWYWHFVDVIWLFLYMSIYWWGS |
Interaction
Subunit
Component of the cytochrome c oxidase (complex IV, CIV), a multisubunit enzyme composed of 14 subunits. The complex is composed of a catalytic core of 3 subunits MT-CO1, MT-CO2 and MT-CO3, encoded in the mitochondrial DNA, and 11 supernumerary subunits COX4I, COX5A, COX5B, COX6A, COX6B, COX6C, COX7A, COX7B, COX7C, COX8 and NDUFA4, which are encoded in the nuclear genome. The complex exists as a monomer or a dimer and forms supercomplexes (SCs) in the inner mitochondrial membrane with NADH-ubiquinone oxidoreductase (complex I, CI) and ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII), resulting in different assemblies (supercomplex SCI1III2IV1 and megacomplex MCI2III2IV2).
Structure
Sequence
- Sequence statusComplete
- Length261
- Mass (Da)29,759
- Last updated2002-03-27 v2
- ChecksumFD9CFE26D44EAAF6
Features
Showing features for sequence conflict.
Type | ID | Position(s) | Description | |||
---|---|---|---|---|---|---|
Sequence conflict | 55 | in Ref. 1; CAA72750 | ||||
Sequence: I → V | ||||||
Sequence conflict | 107 | in Ref. 1; CAA72750 | ||||
Sequence: A → P |
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
Y12025 EMBL· GenBank· DDBJ | CAA72750.1 EMBL· GenBank· DDBJ | Genomic DNA | ||
AF338715 EMBL· GenBank· DDBJ | AAK53349.1 EMBL· GenBank· DDBJ | Genomic DNA |