EC Number   |
General Information |
Reference |
|---|
    7.1.1.6 | evolution |
cytochrome bc1-complexes of animals and bacteria, as well as related cytochrome b6 f complexes of plants and cyanobacteria are dimeric quinol:cytochrome c/plastocyanin oxidoreductases capable of translocating protons across energy-converting membranes. These enzymes oxidize two quinolmolecules in their catalytic centers P to yield one quinol molecule in another catalytic center N. The simplest cytochrome bc1-complexes of Rhodobacter capsulatus, which contains only 3 subunits, matches the structure of the three catalytic subunits of mitochondrial bc1 |
724409 |
| 7.1.1.6 | more |
proton uptake pathway from the electrochemically negative (n) aqueous phase to the n-side quinone binding site of the complex, and a probable route for proton exit to the positive phase resulting from quinol oxidation, overview. The simplest n-side proton pathway extends from the aqueous phase via Asp20 and Arg207 (cytochrome b6 subunit) to quinone bound axially to heme cn. On the positive side, the heme-proximal Glu78 (subunit IV), which accepts protons from plastosemiquinone, defines a route for H+ transfer to the aqueous phase |
726397 |
| 7.1.1.6 | more |
Q-cycle in the cytochrome bc1 complex using the X-ray structure of the three catalytic subunits of a dimeric bc1 of phototrophic bacteria, i.e. the X-ray structure of the bc1 of Rhodobacter sphaeroides, PDB entry 2QJY, modificationss of Mitchell's Q-cycle, detailed overview |
724409 |
| 7.1.1.6 | physiological function |
cytochrome b6 f catalyzes quinone redox reactions within photosynthetic membranes to generate a transmembrane proton electrochemical gradient for ATP synthesis. A key step involves the transfer of an electron from the [2Fe-2S] cluster of the iron-sulfur protein extrinsic domain to the cytochrome f heme across a distance of 26 A, which is too large for competent electron transfer but could be bridged by translation-rotation of the iron-sulfur protein |
724376 |
| 7.1.1.6 | physiological function |
the membrane-embedded cytochrome b6f complex mediates electron transport between the photosystem II and photosystem I reaction center complexes in oxygenic photosynthesis |
712236 |
| 7.1.1.6 | physiological function |
the pigment-protein assembly of the Cyt b6f complex per se is crucial for photo-protection |
713207 |
| 7.1.1.6 | physiological function |
the spinach complex contains diaphorase activity diagnostic of the 35 kDa petH polypeptide and is active in facilitating ferredoxin-dependent electron transfer from NADPH to the cytochrome b6f complex |
-, 712949 |
| 7.1.1.6 | physiological function |
the subunit IV binds single molecules of chlorophyll alpha and beta-carotene, which are likely to be involved in photoprotection |
724409 |
| 7.1.1.6 | physiological function |
two-thirds of the proton gradient used for transmembrane free energy storage in oxygenic photosynthesis is generated by the cytochrome b6f complex |
726397 |
