Function and Biology

Structure of the cytochrome b6f (plastohydroquinone : plastocyanin oxidoreductase) from Chlamydomonas reinhardtii

Source organism: Chlamydomonas reinhardtii
Biochemical function: electron transfer activity
Biological process: photosynthesis
Cellular component: membrane

EC 7.1.1.6: Plastoquinol--plastocyanin reductase

Reaction catalysed:
Plastoquinol + 2 oxidized plastocyanin + 2 H(+)(Side 1) = plastoquinone + 2 reduced plastocyanin + 4 H(+)(Side 2)
Systematic name:
Plastoquinol:oxidized-plastocyanin oxidoreductase
Alternative Name(s):
  • Cytochrome b6/f complex
  • Cytochrome b6f complex
  • Plastoquinol/plastocyanin oxidoreductase

Sequence families

Pfam Protein families (Pfam)
PF05115
Domain description: Cytochrome B6-F complex subunit VI (PetL)
Occurring in:
  1. Cytochrome b6-f complex subunit 6
1 copy of Pfam domain PF05115 (Cytochrome B6-F complex subunit VI (PetL)) in Cytochrome b6-f complex subunit 6 in PDB 1q90.

PF08041
Domain description: PetM family of cytochrome b6f complex subunit 7
Occurring in:
  1. Cytochrome b6-f complex subunit 7, chloroplastic
1 copy of Pfam domain PF08041 (PetM family of cytochrome b6f complex subunit 7) in Cytochrome b6-f complex subunit 7, chloroplastic in PDB 1q90.

PF01333
Domain description: Apocytochrome F, C-terminal
Occurring in:
  1. Cytochrome f
1 copy of Pfam domain PF01333 (Apocytochrome F, C-terminal) in Cytochrome f in PDB 1q90.

PF02529
Domain description: Cytochrome B6-F complex subunit 5
Occurring in:
  1. Cytochrome b6-f complex subunit 5
1 copy of Pfam domain PF02529 (Cytochrome B6-F complex subunit 5) in Cytochrome b6-f complex subunit 5 in PDB 1q90.

PF16639
Domain description: Apocytochrome F, N-terminal
Occurring in:
  1. Cytochrome f
1 copy of Pfam domain PF16639 (Apocytochrome F, N-terminal) in Cytochrome f in PDB 1q90.

PF00355
Domain description: Rieske [2Fe-2S] domain
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
1 copy of Pfam domain PF00355 (Rieske [2Fe-2S] domain) in Cytochrome b6-f complex iron-sulfur subunit, chloroplastic in PDB 1q90.

PF00033
Domain description: Cytochrome b/b6/petB
Occurring in:
  1. Cytochrome b6
1 copy of Pfam domain PF00033 (Cytochrome b/b6/petB) in Cytochrome b6 in PDB 1q90.

PF00032
Domain description: Cytochrome b(C-terminal)/b6/petD
Occurring in:
  1. Cytochrome b6-f complex subunit 4
1 copy of Pfam domain PF00032 (Cytochrome b(C-terminal)/b6/petD) in Cytochrome b6-f complex subunit 4 in PDB 1q90.

PF03742
Domain description: PetN
Occurring in:
  1. Cytochrome b6-f complex subunit 8, chloroplastic
1 copy of Pfam domain PF03742 (PetN) in Cytochrome b6-f complex subunit 8, chloroplastic in PDB 1q90.

InterPro InterPro annotations
IPR002325
Domain description: Cytochrome f
Occurring in:
  1. Cytochrome f
IPR005805
Domain description: Rieske iron-sulphur protein, C-terminal
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
IPR005798
Domain description: Cytochrome b/b6, C-terminal
Occurring in:
  1. Cytochrome b6-f complex subunit 4
IPR005797
Domain description: Cytochrome b/b6, N-terminal
Occurring in:
  1. Cytochrome b6
IPR005497
Domain description: Cytochrome b6-f complex, subunit 8
Occurring in:
  1. Cytochrome b6-f complex subunit 8, chloroplastic
IPR003683
Domain description: Cytochrome b6/f complex, subunit 5
Occurring in:
  1. Cytochrome b6-f complex subunit 5
IPR036922
Domain description: Rieske [2Fe-2S] iron-sulphur domain superfamily
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
IPR024058
Domain description: Cytochrome f transmembrane anchor
Occurring in:
  1. Cytochrome f
IPR036150
Domain description: Cytochrome b/b6, C-terminal domain superfamily
Occurring in:
  1. Cytochrome b6-f complex subunit 4
IPR007802
Domain description: Cytochrome b6-f complex subunit 6
Occurring in:
  1. Cytochrome b6-f complex subunit 6
IPR024094
Domain description: Cytochrome f large domain
Occurring in:
  1. Cytochrome f
IPR036826
Domain description: Cytochrome f large domain superfamily
Occurring in:
  1. Cytochrome f
IPR023530
Domain description: Cytochrome b6, PetB
Occurring in:
  1. Cytochrome b6
IPR036099
Domain description: Cytochrome b6/f complex, subunit 5 superfamily
Occurring in:
  1. Cytochrome b6-f complex subunit 5
IPR011054
Domain description: Rudiment single hybrid motif
Occurring in:
  1. Cytochrome f
IPR016174
Domain description: Di-haem cytochrome, transmembrane
Occurring in:
  1. Cytochrome b6
IPR036143
Domain description: Cytochrome b6-f complex, subunit 8 superfamily
Occurring in:
  1. Cytochrome b6-f complex subunit 8, chloroplastic
IPR017941
Domain description: Rieske [2Fe-2S] iron-sulphur domain
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
IPR027387
Domain description: Cytochrome b/b6-like domain superfamily
Occurring in:
  1. Cytochrome b6
IPR005870
Domain description: Cytochrome b6/f complex, subunit IV
Occurring in:
  1. Cytochrome b6-f complex subunit 4
IPR012595
Domain description: PetM of cytochrome b6/f complex subunit 7
Occurring in:
  1. Cytochrome b6-f complex subunit 7, chloroplastic

Structure domains

CATH CATH domains
2.60.40.830
Class: Mainly Beta
Architecture: Sandwich
Topology: Immunoglobulin-like
Homology: Cytochrome f large domain
Occurring in:
  1. Cytochrome f
1 copy of CATH domain 2.60.40.830 (Immunoglobulin-like) in Cytochrome f in PDB 1q90.
1.10.287.980
Class: Mainly Alpha
Architecture: Orthogonal Bundle
Topology: Helix Hairpins
Homology: plastocyanin oxidoreductase
Occurring in:
  1. Cytochrome b6-f complex subunit 4
1 copy of CATH domain 1.10.287.980 (Helix Hairpins) in Cytochrome b6-f complex subunit 4 in PDB 1q90.
2.40.50.100
Class: Mainly Beta
Architecture: Beta Barrel
Topology: OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homology: OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Occurring in:
  1. Cytochrome f
1 copy of CATH domain 2.40.50.100 (OB fold (Dihydrolipoamide Acetyltransferase, E2P)) in Cytochrome f in PDB 1q90.
1.20.810.10
Class: Mainly Alpha
Architecture: Up-down Bundle
Topology: Cytochrome Bc1 Complex; Chain C
Homology: Cytochrome Bc1 Complex; Chain C
Occurring in:
  1. Cytochrome b6
1 copy of CATH domain 1.20.810.10 (Cytochrome Bc1 Complex; Chain C) in Cytochrome b6 in PDB 1q90.
1.20.5.510
Class: Mainly Alpha
Architecture: Up-down Bundle
Topology: Single alpha-helices involved in coiled-coils or other helix-helix interfaces
Homology: Single helix bin
Occurring in:
  1. Cytochrome b6-f complex subunit 4
1 copy of CATH domain 1.20.5.510 (Single alpha-helices involved in coiled-coils or other helix-helix interfaces) in Cytochrome b6-f complex subunit 4 in PDB 1q90.
2.102.10.10
Class: Mainly Beta
Architecture: 3-layer Sandwich
Topology: Rieske Iron-sulfur Protein
Homology: Rieske [2Fe-2S] iron-sulphur domain
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
1 copy of CATH domain 2.102.10.10 (Rieske Iron-sulfur Protein) in Cytochrome b6-f complex iron-sulfur subunit, chloroplastic in PDB 1q90.
SCOP SCOP annotations
49442
Class: All beta proteins
Fold: Common fold of diphtheria toxin/transcription factors/cytochrome f
Superfamily: Cytochrome f, large domain
Occurring in:
  1. Cytochrome f
1 copy of SCOP domain 49442 (Cytochrome f, large domain) in Cytochrome f in PDB 1q90.
81501
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: ISP transmembrane anchor
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
1 copy of SCOP domain 81501 (ISP transmembrane anchor) in Cytochrome b6-f complex iron-sulfur subunit, chloroplastic in PDB 1q90.
103452
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: PetN subunit of the cytochrome b6f complex
Occurring in:
  1. Cytochrome b6-f complex subunit 8, chloroplastic
1 copy of SCOP domain 103452 (PetN subunit of the cytochrome b6f complex) in Cytochrome b6-f complex subunit 8, chloroplastic in PDB 1q90.
51256
Class: All beta proteins
Fold: Barrel-sandwich hybrid
Superfamily: Rudiment single hybrid motif
Occurring in:
  1. Cytochrome f
1 copy of SCOP domain 51256 (Cytochrome f, small domain) in Cytochrome f in PDB 1q90.
103447
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: PetG subunit of the cytochrome b6f complex
Occurring in:
  1. Cytochrome b6-f complex subunit 5
1 copy of SCOP domain 103447 (PetG subunit of the cytochrome b6f complex) in Cytochrome b6-f complex subunit 5 in PDB 1q90.
103442
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: PetM subunit of the cytochrome b6f complex
Occurring in:
  1. Cytochrome b6-f complex subunit 7, chloroplastic
1 copy of SCOP domain 103442 (PetM subunit of the cytochrome b6f complex) in Cytochrome b6-f complex subunit 7, chloroplastic in PDB 1q90.
81647
Class: Membrane and cell surface proteins and peptides
Fold: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)
Superfamily: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)
Occurring in:
  1. Cytochrome b6-f complex subunit 4
1 copy of SCOP domain 81647 (a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)) in Cytochrome b6-f complex subunit 4 in PDB 1q90.
103437
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: PetL subunit of the cytochrome b6f complex
Occurring in:
  1. Cytochrome b6-f complex subunit 6
1 copy of SCOP domain 103437 (PetL subunit of the cytochrome b6f complex) in Cytochrome b6-f complex subunit 6 in PDB 1q90.
81642
Class: Membrane and cell surface proteins and peptides
Fold: Heme-binding four-helical bundle
Superfamily: Transmembrane di-heme cytochromes
Occurring in:
  1. Cytochrome b6
1 copy of SCOP domain 81642 (Cytochrome b of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)) in Cytochrome b6 in PDB 1q90.
103432
Class: Membrane and cell surface proteins and peptides
Fold: Single transmembrane helix
Superfamily: Cytochrome f subunit of the cytochrome b6f complex, transmembrane anchor
Occurring in:
  1. Cytochrome f
1 copy of SCOP domain 103432 (Cytochrome f subunit of the cytochrome b6f complex, transmembrane anchor) in Cytochrome f in PDB 1q90.
50023
Class: All beta proteins
Fold: ISP domain
Superfamily: ISP domain
Occurring in:
  1. Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
1 copy of SCOP domain 50023 (Rieske iron-sulfur protein (ISP)) in Cytochrome b6-f complex iron-sulfur subunit, chloroplastic in PDB 1q90.