COX6A1
Description
The COX6A1 (cytochrome c oxidase subunit 6A1) is a protein-coding gene located on chromosome 12.
Cytochrome c oxidase subunit 6A1, mitochondrial is a protein that in humans is encoded by the COX6A1 gene. Cytochrome c oxidase 6A1 is a subunit of the cytochrome c oxidase complex, also known as Complex IV, the last enzyme in the mitochondrial electron transport chain. A mutation of the COX6A1 gene is associated with a recessive axonal or mixed form of Charcot-Marie-Tooth disease.
== Structure == The COX6A1 gene, located on the q arm of chromosome 12 in position 24.2, contains 3 exons and is 2,653 base pairs in length. The COX6A1 protein weighs 12 kDa and is composed of 109 amino acids. The protein is a subunit of Complex IV, a heteromeric complex consisting of 3 catalytic subunits encoded by mitochondrial genes and multiple structural subunits encoded by nuclear genes. This nuclear gene encodes polypeptide 1 (liver isoform) of subunit VIa, and polypeptide 1 is found in all non-muscle tissues. Polypeptide 2 (heart/muscle isoform) of subunit VIa is encoded by a different gene, COX6A2, and is present only in striated muscles. These two polypeptides share 66% amino acid sequence identity.
== Function == Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain.
COX6A1 is a crucial component of cytochrome c oxidase (COX), the terminal enzyme of the mitochondrial respiratory chain. This chain comprises three multi-subunit complexes: succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (complex III, CIII), and cytochrome c oxidase (complex IV, CIV). These complexes work together to transfer electrons from NADH and succinate to molecular oxygen. This process generates an electrochemical gradient across the inner mitochondrial membrane, driving transmembrane transport and ATP synthase activity. COX specifically catalyzes the reduction of oxygen to water. Electrons from reduced cytochrome c in the intermembrane space (IMS) are transferred through the dinuclear copper A center (CU(A)) of subunit 2 and heme A of subunit 1 to the active site in subunit 1. This active site, a binuclear center (BNC) formed by heme A3 and copper B (CU(B)), utilizes these electrons and protons from the mitochondrial matrix to reduce molecular oxygen to two water molecules.
COX6A1 is also known as CMTRID, COX6A, COX6AL.
