O21403 · COX3_STRCA

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

GO annotations

AspectTerm
Cellular Componentmitochondrial inner membrane
Cellular Componentrespiratory chain complex IV
Molecular Functioncytochrome-c oxidase activity
Biological Processaerobic electron transport chain

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Cytochrome c oxidase subunit 3
  • EC number
  • Alternative names
    • Cytochrome c oxidase polypeptide III

Gene names

    • Name
      MT-CO3
    • Synonyms
      COIII, COXIII, MTCO3

Encoded on

  • Mitochondrion

Organism names

  • Taxonomic identifier
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Archelosauria > Archosauria > Dinosauria > Saurischia > Theropoda > Coelurosauria > Aves > Palaeognathae > Struthioniformes > Struthionidae > Struthio

Accessions

  • Primary accession
    O21403
  • Secondary accessions
    • Q957X5

Subcellular Location

Features

Showing features for topological domain, transmembrane.

TypeIDPosition(s)Description
Topological domain1-15Mitochondrial matrix
Transmembrane16-34Helical; Name=I
Topological domain35-40Mitochondrial intermembrane
Transmembrane41-66Helical; Name=II
Topological domain67-72Mitochondrial matrix
Transmembrane73-105Helical; Name=III
Topological domain106-128Mitochondrial intermembrane
Transmembrane129-152Helical; Name=IV
Topological domain153-155Mitochondrial matrix
Transmembrane156-183Helical; Name=V
Topological domain184-190Mitochondrial intermembrane
Transmembrane191-223Helical; Name=VI
Topological domain224-232Mitochondrial matrix
Transmembrane233-256Helical; Name=VII
Topological domain257-261Mitochondrial intermembrane

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00001838571-261Cytochrome c oxidase subunit 3

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

Family & Domains

Sequence similarities

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    261
  • Mass (Da)
    29,759
  • Last updated
    2002-03-27 v2
  • Checksum
    FD9CFE26D44EAAF6
MAHQAHSYHMVDPSPWPIFGATAALLTTSGLIMWFHYNSLYLLTLGLLSMFLVMIQWWRDIVRESTFQGHHTPTVQKGLRYGMILFITSEAFFFLGFFWAFFHSSLAPTPELGAQWPPTGINPLNPLEVPLLNTAILLASGVTVTWAHHSITESNRKQAIHALSLTIILGFYFTALQAMEYHEASFSIADGVYGSTFFVATGFHGLHVIIGSSFLTVCLLRLIKFHFTTNHHFGFEAAAWYWHFVDVIWLFLYMSIYWWGS

Features

Showing features for sequence conflict.

TypeIDPosition(s)Description
Sequence conflict55in Ref. 1; CAA72750
Sequence conflict107in Ref. 1; CAA72750

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
Y12025
EMBL· GenBank· DDBJ
CAA72750.1
EMBL· GenBank· DDBJ
Genomic DNA
AF338715
EMBL· GenBank· DDBJ
AAK53349.1
EMBL· GenBank· DDBJ
Genomic DNA

Genome annotation databases

Similar Proteins

Disclaimer

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