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Literature summary for 7.1.1.6 extracted from

  • Mulkidjanian, A.
    Activated Q-cycle as a common mechanism for cytochrome bc1 and cytochrome b6f complexes (2010), Biochim. Biophys. Acta, 1797, 1858-1868.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
additional information the bf complex, however, can be dark-activated via reduction of heme cn by ferredoxin Rhodobacter capsulatus

Inhibitors

Inhibitors Comment Organism Structure
(E)-beta-methoxyacrylate stilbene weak inhibition, retards concurrently the flashinduced re-reduction of cytochrome f, the oxidation of cytochrome b6 and the onset of voltage generation, thereby hardly affecting the rate of the flash-induced cytochrome b6 reduction and the steady turnover of the bf Rhodobacter capsulatus
2-n-Nonyl-4-hydroxyquinoline N-oxide weak inhibition, retards concurrently the flashinduced re-reduction of cytochrome f, the oxidation of cytochrome b6 and the onset of voltage generation, thereby hardly affecting the rate of the flash-induced cytochrome b6 reduction and the steady turnover of the bf Rhodobacter capsulatus

Localization

Localization Comment Organism GeneOntology No. Textmining
membrane
-
Rhodobacter capsulatus 16020
-

Metals/Ions

Metals/Ions Comment Organism Structure
Zn2+ concurrent action of Zn2+ ions on the re-reduction of cytochrome c1 by the Rieske protein, voltage generation, and proton release from the bc1 Rhodobacter capsulatus

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
plastoquinol + 2 oxidized plastocyanin + 2 H+[side 1] Rhodobacter capsulatus
-
plastoquinone + 2 reduced plastocyanin + 2 H+[side 2]
-
?

Organism

Organism UniProt Comment Textmining
Rhodobacter capsulatus
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
plastoquinol + 2 oxidized plastocyanin + 2 H+[side 1]
-
Rhodobacter capsulatus plastoquinone + 2 reduced plastocyanin + 2 H+[side 2]
-
?

Subunits

Subunits Comment Organism
dimer
-
Rhodobacter capsulatus

Synonyms

Synonyms Comment Organism
cytochrome b6 f complex
-
Rhodobacter capsulatus
quinol:plastocyanin oxidoreductase
-
Rhodobacter capsulatus

General Information

General Information Comment Organism
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 Rhodobacter capsulatus
additional information 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 Rhodobacter capsulatus
physiological function the subunit IV binds single molecules of chlorophyll alpha and beta-carotene, which are likely to be involved in photoprotection Rhodobacter capsulatus