chromatophore cytochrome bc1 complex

cellstructuremech:chromatophore_cytochrome_bc1_complex · Energy complex · Multiprotein complex · Proposed

A purple-bacterial chromatophore membrane cytochrome bc1 protein complex that oxidizes quinol from the chromatophore quinone pool and returns electrons toward reaction-center antenna cores through soluble cytochrome c2 during cyclic photosynthetic electron transport. [DOI:10.1074/jbc.M412088200]

Synonyms: cytochrome bc1 complex

Part of: plasma membrane-derived chromatophore membrane (GO:0042717)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Taxonomic distribution

NCBITaxon:2 Bacteria — RARE: Chromatophore cytochrome bc1 complexes occur in purple-bacterial photosynthetic membranes rather than broadly across bacteria. [uniprot.location:SL-0042 — Cellular chromatophore membrane]

Canonical examples

NCBITaxon:1063 Cereibacter sphaeroides — Purple photosynthetic bacterium, still commonly cited under the synonym Rhodobacter sphaeroides, whose chromatophore quinone traffic between reaction-center antenna cores and cytochrome bc1 has been modeled. [DOI:10.1074/jbc.M412088200]

Functions

photosynthetic electron transport chain GO:0009767 — The chromatophore cytochrome bc1 complex reoxidizes quinol carriers from reaction-center cores and returns electrons toward the reaction center through cytochrome c2.
- DOI:10.1074/jbc.M412088200 Comayras et al. 2005 modeled chromatophore quinone-domain behavior around cytochrome bc1 and reaction-center antenna complexes.

Mechanism graphs

Chromatophore cytochrome bc1 turns over the quinone pool (FUNCTION)

In purple-bacterial chromatophore membranes, the cytochrome bc1 complex oxidizes quinol produced by reaction-center antenna cores and passes electrons toward cytochrome c2 during cyclic photosynthetic electron transport.

Subject	Predicate	Object	Evidence
chromatophore cytochrome bc1 complex	is part of	plasma membrane-derived chromatophore membrane	`uniprot.location:SL-0042` — Cellular chromatophore membrane UniProt SL-0042 lists cytochrome bc1 among the complexes contained in cellular chromatophore membranes.
RC-LH1-PufX core complex	reduces	quinone pool	`DOI:10.1074/jbc.M412088200` Comayras et al. 2005 model quinone traffic between Rhodobacter reaction-center antenna complexes and cytochrome bc1 in chromatophores.
chromatophore cytochrome bc1 complex	oxidizes	quinone pool	`DOI:10.1074/jbc.M412088200` Comayras et al. 2005 modeled quinone-domain behavior around cytochrome bc1 in Rhodobacter sphaeroides chromatophores.
chromatophore cytochrome bc1 complex	reduces	cytochrome c2	`DOI:10.1074/jbc.M412088200` Comayras et al. 2005 connect cytochrome bc1 to the Rhodobacter photosynthetic electron-transfer loop.
chromatophore cytochrome bc1 complex	contributes to	photosynthetic electron transport chain	`DOI:10.1074/jbc.M412088200` Comayras et al. 2005 studied cytochrome bc1 placement within the organized Rhodobacter photosynthetic apparatus.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral component groundings for the purple-bacterial cytochrome b, cytochrome c1 and Rieske iron-sulfur subunits before adding subunit-level component rows. The chromatophore cytochrome bc1 complex is modeled as a record-level energy complex, but this first record does not guess exact InterPro, Pfam or NCBIfam terms for its taxon-agnostic subunits.

Evidence

GO:0042717 Gene Ontology cellular-component term for the plasma membrane-derived chromatophore membrane that houses purple-bacterial cytochrome bc1.
GO:0009767 Gene Ontology biological-process term for the photosynthetic electron transport chain.
uniprot.location:SL-0042 — Cellular chromatophore membrane UniProt Subcellular Location entry for the cellular chromatophore membrane; lists cytochrome bc1 among the complexes contained in purple-bacterial chromatophore membranes.
DOI:10.1074/jbc.M412088200 Comayras, Jungas and Lavergne 2005, Functional Consequences of the Organization of the Photosynthetic Apparatus in Rhodobacter sphaeroides, Journal of Biological Chemistry.

Curation history

2026-09-13T07:27:38Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T07:28:09Z codex · EXPANDED_RECORD — Added cytochrome bc1 synonymy, chromatophore parthood, purple-bacterial scope, a Cereibacter example, photosynthetic electron-transport function, GO/UniProt/literature evidence, a nonmechanistic quinol-oxidation graph, and a cytochrome bc1 subunit-boundary TODO.

Source: data/structures/energy_complex/chromatophore_cytochrome_bc1_complex.yaml