COX6B1
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.
Involvement in disease
Mitochondrial complex IV deficiency, nuclear type 7
MC4DN7
An autosomal recessive mitochondrial disorder characterized by encephalomyopathy resulting in variable clinical manifestations. Features include muscle weakness, gait disturbances, neurodegeneration, cognitive decline, metabolic acidosis, feeding difficulties, poor overall growth, cortical visual impairment, and hypertrophic cardiomyopathy. Serum lactate levels are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.
None
The disease is caused by variants affecting the gene represented in this entry.
Pathway
Energy metabolism; oxidative phosphorylation.
Sequence Similarities
Belongs to the cytochrome c oxidase subunit 6B family.
Cellular localization
- Mitochondrion inner membrane
- Peripheral membrane protein
- Intermembrane side
Alternative names
COX6B, COX6B1, Cytochrome c oxidase subunit 6B1, Cytochrome c oxidase subunit VIb isoform 1, COX VIb-1