UniProt:P00424 COX5A

chain
  • transit peptide:1-20
  • chain:21-153
checksum 1B1F8A3FE12CF783
comment
  • 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 COX2 and heme A of COX1 to the active site in COX1, 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.PATHWAY Energy metabolism; oxidative phosphorylation.SUBUNIT Component of the cytochrome c oxidase (complex IV, CIV), a multisubunit enzyme composed of 12 subunits. The complex is composed of a catalytic core of 3 subunits COX1, COX2 and COX3, encoded in the mitochondrial DNA, and 9 supernumerary subunits COX4, COX5A (or COX5B), COX6, COX7, COX8, COX9, COX12, COX13 and COX26, which are encoded in the nuclear genome (PubMed:30598554, PubMed:30598556, PubMed:7851399). COX5A is the predominant subunit V during aerobic/normoxic growth, it gets replaced by COX5B under anaerobic/hypoxic conditions (PubMed:2546055). The complex exists as a monomer or a dimer and forms supercomplexes (SCs) in the inner mitochondrial membrane with a dimer of ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII), resulting in 2 different assemblies (supercomplexes III(2)IV and III(2)IV(2)) (PubMed:10764779, PubMed:10775262, PubMed:30598554, PubMed:30598556). COX5A interacts with COR1, CYT1 and QCR6 at the CIII-CIV interface (PubMed:30598554, PubMed:30598556).INTERACTION By oxygen at the level of transcription through heme (PubMed:2546055). Expression drops rapidly when the oxygen concentration falls below 0.5 uM O(2) (PubMed:9169434).MISCELLANEOUS Present with 3670 molecules/cell in log phase SD medium.SIMILARITY Belongs to the cytochrome c oxidase IV family.
crossReference
databaseName UniProt
dbId 88512
description
  • recommendedName: Cytochrome c oxidase subunit 5A, mitochondrial alternativeName: Cytochrome c oxidase polypeptide Va
displayName UniProt:P00424 COX5A
geneName
  • COX5A
  • YNL052W
  • N2474
  • YNL2474W
identifier P00424
isSequenceChanged false
keyword
  • 3D-structure
  • Direct protein sequencing
  • Membrane
  • Mitochondrion
  • Mitochondrion inner membrane
  • Oxidoreductase
  • Reference proteome
  • Transit peptide
  • Transmembrane
  • Transmembrane helix
modified [InstanceEdit:9983091] Weiser, Joel, 2026-02-20
moleculeType Protein
name
  • COX5A
otherIdentifier
  • 855675
  • GO:0003674
  • GO:0004129
  • GO:0005575
  • GO:0005739
  • GO:0005743
  • GO:0005751
  • GO:0005758
  • GO:0006091
  • GO:0006119
  • GO:0006123
  • GO:0006811
  • GO:0016020
  • GO:0016021
  • GO:0016491
  • GO:0022857
  • GO:0045277
  • GO:0055085
  • GO:1902600
physicalEntity
referenceDatabase [ReferenceDatabase:2] UniProt
referenceGene
referenceTranscript
schemaClass ReferenceGeneProduct
secondaryIdentifier
  • COX5A_YEAST
  • D6W1C7
sequenceLength 153
species [Species:68322] Saccharomyces cerevisiae
stId uniprot:P00424
url http://purl.uniprot.org/uniprot/P00424
Cite Us!