InterPro domain: IPR002326

Cytochrome bc1 complex (ubiquinol:ferricytochrome c oxidoreductase) is found in mitochondria, photosynthetic bacteria and other prokaryotes. It is minimally composed of three subunits: cytochrome b, carrying a low- and a high-potential haem group; cytochrome c1 (cyt c1); and a high-potential Rieske iron-sulphur protein. The general function of the complex is electron transfer between two mobile redox carriers, ubiquinol and cytochrome c; the electron transfer is coupled with proton translocation across the membrane, thus generating proton-motive force in the form of anelectrochemical potential that can drive ATP synthesis. In its structure andfunctions, the cytochrome bc1 complex bears extensive analogy to thecytochrome b6f complex of chloroplasts and cyanobacteria; cyt c1 plays ananalogous role to cytochrome f, in spite of their different structures [ 1 ].

This entry also includes Nitrosomonas europaea petC, which is a subunit of the ammonia monooxygenase complex that catalyzes the oxidation of ammonia to hydroxylamine, the first reaction in the process of ammonia oxidation to nitrite [ 2 ].

1. Cytochrome f revealed. Trends Biochem. Sci. 20, 217-8
2. A soluble form of ammonia monooxygenase in Nitrosomonas europaea. Biol. Chem. 390, 863-73