Cytochrome c oxidase subunit 5A, mitochondrial (COX5A)
The protein contains 150 amino acids for an estimated molecular weight of 16762 Da.
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. (updated: Feb. 26, 2020)
Protein identification was indicated in the following studies:
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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The reference OMIM entry for this protein is 603773
Cytochrome c oxidase, subunit va; cox5a
CLONING
Cytochrome c oxidase (COX), the terminal component of the respiratory chain complex of most aerobic organisms, is composed of 13 subunits in mammals. See 123870. The COX Va subunit is found in all mammalian tissues. By screening a fetal muscle library with an oligonucleotide based on the amino acid sequence of bovine COX Va, Rizzuto et al. (1988) isolated a partial cDNA encoding the human homolog. They screened an endothelial cell library with the partial cDNA and recovered a cDNA corresponding to the complete COX Va coding region. The predicted 150-amino acid human protein contains a 41-amino acid presequence. The authors reported that although the presequence is rich in basic and hydroxylated residues, it differs from those of previously isolated COX subunits in that it also contains a negatively charged residue. The mature human COX Va polypeptide shares 35% and 95% protein sequence identity with the corresponding S. cerevisiae COX subunit VI and bovine COX Va, respectively. Northern blot analysis revealed that COX Va was expressed as a 750-nucleotide mRNA in all human tissues tested. Southern blot analysis indicated that the COX Va gene is part of a multicopy family in the human genome.MAPPING
By fluorescence in situ hybridization and by radiation hybrid mapping, Hofmann et al. (1998) mapped the COX5A gene to chromosome 15q25, and a COX5A pseudogene, COX5AP1, to 14q22. ... More on the omim web site
June 30, 2020: Protein entry updated
Automatic update: OMIM entry 603773 was added.
March 3, 2020: Protein entry updated
Automatic update: Entry updated from uniprot information.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).