Cytochrome bc1 complex
Template:STRUCTURE 1bcc Cytochrome bc1 (Cbc1) functions as the central pump which transfers protons across the cell membrane. The protons are used to power the rotation of ATP synthase. Cbc1 binds ubiquinol which carries hydrogen atoms. Cbc1 separates the protons and the electrons. The protons are released in the inner side of the membrane for use by ATP synthase and the electrons are transferred to cytochrome c or to the outer side of the membrane. Cbc1 is a dimeric protein composed of 11 proteins and cofactors which include heme-carrying proteins like cytochrome b (Cb) and cytochrome c1 (Cc1) and iron-sulfur cluster proteins like Rieske Fe-S protein (RISP). Plants use cytochrome b6f in the same manner binding plastoquinol as a hydrogen carrier. Stigmatellin is an inhibitor of the Cbc1 electron transfer by binding to its quinone oxidation site. Antimycin inhibits Cbc1 by binding to its quinone reduction site.
More details in Complex_III_of_Electron_Transport_Chain.
3D structures of cytochrome bc13D structures of cytochrome bc1
Updated on 18-March-2015
2fyn - RsCb (mutant) + Cc1 + RISP – Rhodobacter sphaeroides
1zrt - Cb + Cc1 + RISP – Rhodobacter capsulatus
1bgy, 1be3, 1l0n, 1ntm - bCb + bCc1 + RISP – bovine
1qcr - bCb + bCc1 + RISP – Cα model
1sqp, 2fyu, 1l0l, 1ntk, 1pp9, 1ppj, 1sqb, 2a06, 1sqv, 1sqx, 1sqq - bCb + bCc1 + RISP + inhibitor
4d6u - bCb + bCc1 + RISP + antimalarial pyridone
1ntz - bCb + bCc1 + RISP + ubiquinone
1nu1 - bCb + bCc1 + RISP + quinolone derivative
2qjk - RsCb (mutant) + RsCc1 + RISP + inhibitor
2qjp - RsCb + RsCc1 + RISP + inhibitor
2qjy - RsCb (mutant) + RsCc1 + RISP (mutant) + inhibitor
2ibz, 1kyo, 1kb9, 1p84 - yCb + yCc1 + RISP + inhibitor - yeast
3cx5 - yCb + yCc1 + RISP
1ezv - yCb + yCc1 + RISP + antibody
2yiu - Cb + Cc1 + RISP – Paracoccus denitrificans
1qcr - bCb + bCc1 + RISP – bovine – Cα model
3cxh, 3h1h, 1bcc, 3h1h - cCb + cCc1 + RISP - chicken
3cwb, 3h1i, 3h1j, 3h1k, 3h1l, 3l70, 3l71, 3l72, 3l73, 3l74, 3l75, 3tgu, 3bcc, 2bcc, 3h1i - cCb + cCc1 + RISP + inhibitor