Annotations: 6KLS

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
B	PF00032	e6klsB1	A: alpha bundles	X: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) (From Topology)	H: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) (From Topology)	T: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)	F: PF00032	ECOD (1.6)
B	PF00033	e6klsB2	A: alpha bundles	X: Transmembrane heme-binding four-helical bundle (From Homology)	H: Transmembrane heme-binding four-helical bundle	T: Transmembrane di-heme cytochromes	F: PF00033	ECOD (1.6)
E	PF00032	e6klsE2	A: alpha bundles	X: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) (From Topology)	H: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase) (From Topology)	T: a domain/subunit of cytochrome bc1 complex (Ubiquinol-cytochrome c reductase)	F: PF00032	ECOD (1.6)
E	PF00033	e6klsE1	A: alpha bundles	X: Transmembrane heme-binding four-helical bundle (From Homology)	H: Transmembrane heme-binding four-helical bundle	T: Transmembrane di-heme cytochromes	F: PF00033	ECOD (1.6)
A	F_UNCLASSIFIED	e6klsA2	A: beta sandwiches	X: ISP domain (From Topology)	H: ISP domain (From Topology)	T: ISP domain	F: F_UNCLASSIFIED	ECOD (1.6)
A	PF00355	e6klsA1	A: few secondary structure elements	X: Trm112p-like (From Topology)	H: Trm112p-like (From Topology)	T: Trm112p-like	F: PF00355	ECOD (1.6)
A	F_UNCLASSIFIED	e6klsA3	A: extended segments	X: iron-sulfur subunit (ISP) transmembrane anchor (From Topology)	H: iron-sulfur subunit (ISP) transmembrane anchor (From Topology)	T: iron-sulfur subunit (ISP) transmembrane anchor	F: F_UNCLASSIFIED	ECOD (1.6)
D	F_UNCLASSIFIED	e6klsD1	A: beta sandwiches	X: ISP domain (From Topology)	H: ISP domain (From Topology)	T: ISP domain	F: F_UNCLASSIFIED	ECOD (1.6)
D	PF00355	e6klsD3	A: few secondary structure elements	X: Trm112p-like (From Topology)	H: Trm112p-like (From Topology)	T: Trm112p-like	F: PF00355	ECOD (1.6)
D	F_UNCLASSIFIED	e6klsD2	A: extended segments	X: iron-sulfur subunit (ISP) transmembrane anchor (From Topology)	H: iron-sulfur subunit (ISP) transmembrane anchor (From Topology)	T: iron-sulfur subunit (ISP) transmembrane anchor	F: F_UNCLASSIFIED	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
B	1.20.810.10	Mainly Alpha	Up-down Bundle	Cytochrome Bc1 Complex	Chain C	CATH (utative)
E	1.20.810.10	Mainly Alpha	Up-down Bundle	Cytochrome Bc1 Complex	Chain C	CATH (utative)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
B, E	PF00032	Cytochrome b(C-terminal)/b6/petD (Cytochrom_B_C)	Cytochrome b(C-terminal)/b6/petD	-	Domain
B, E	PF13631	Cytochrome b(N-terminal)/b6/petB (Cytochrom_B_N_2)	Cytochrome b(N-terminal)/b6/petB	-	Domain
A, D	PF00355	Rieske [2Fe-2S] domain (Rieske)	Rieske [2Fe-2S] domain	The rieske domain has a [2Fe-2S] centre. Two conserved cysteines coordinate one Fe ion, while the other Fe ion is coordinated by two conserved histidines. In hyperthermophilic archaea there is a SKTPCX(2-3)C motif at the C-terminus. The cysteines in ...	The rieske domain has a [2Fe-2S] centre. Two conserved cysteines coordinate one Fe ion, while the other Fe ion is coordinated by two conserved histidines. In hyperthermophilic archaea there is a SKTPCX(2-3)C motif at the C-terminus. The cysteines in this motif form a disulphide bridge, which stabilises the protein [4].	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
B, E	cytochrome b subunit	electron transfer activity cation binding ion binding binding metal ion binding small molecule binding	cellular respiration energy derivation by oxidation of organic compounds respiratory electron transport chain cellular metabolic process electron transport chain metabolic process cellular process generation of precursor metabolites and energy	membrane cellular anatomical entity
A, D	Rieske-I iron sulfur protein	oxidoreductase activity catalytic activity monoatomic cation transmembrane transporter activity proton transmembrane transporter activity oxidoreductase activity, acting on diphenols and related substances as donors primary active transmembrane transporter activity electron transfer activity active monoatomic ion transmembrane transporter activity oxidoreduction-driven active transmembrane transporter activity active transmembrane transporter activity inorganic molecular entity transmembrane transporter activity inorganic cation transmembrane transporter activity monoatomic ion transmembrane transporter activity transporter activity oxidoreductase activity catalytic activity monoatomic cation transmembrane transporter activity proton transmembrane transporter activity oxidoreductase activity, acting on diphenols and related substances as donors primary active transmembrane transporter activity electron transfer activity active monoatomic ion transmembrane transporter activity oxidoreduction-driven active transmembrane transporter activity active transmembrane transporter activity inorganic molecular entity transmembrane transporter activity inorganic cation transmembrane transporter activity monoatomic ion transmembrane transporter activity transporter activity ubiquinol-cytochrome-c reductase activity transmembrane transporter activity iron-sulfur cluster binding 2 iron, 2 sulfur cluster binding binding metal cluster binding small molecule binding cation binding ion binding metal ion binding	-	cell periphery plasma membrane membrane cellular anatomical entity membrane-bounded organelle intracellular organelle intracellular anatomical structure organelle intracellular membrane-bounded organelle cytoplasm
C, F	Cytochrome c	binding organic cyclic compound binding tetrapyrrole binding heme binding electron transfer activity cation binding ion binding metal ion binding small molecule binding	-	membrane cellular anatomical entity

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
B, E	IPR036150	Cytochrome b/b6, C-terminal domain superfamily	Homologous Superfamily
B, E	IPR027387	Cytochrome b/b6-like domain superfamily	Homologous Superfamily
B, E	IPR016174	Di-haem cytochrome, transmembrane	Homologous Superfamily
B, E	IPR005798	Cytochrome b/b6, C-terminal	Domain
B, E	IPR005797	Cytochrome b/b6, N-terminal domain	Domain
A, D	IPR017941	Rieske [2Fe-2S] iron-sulphur domain	Domain
A, D	IPR005805	Rieske iron-sulphur protein, C-terminal	Domain
A, D	IPR036922	Rieske [2Fe-2S] iron-sulphur domain superfamily	Homologous Superfamily
A, D	IPR014349	Rieske iron-sulphur protein	Family
A, D	IPR006317	Ubiquinol-cytochrome c reductase, iron-sulphur subunit	Domain
C, F	IPR036909	Cytochrome c-like domain superfamily	Homologous Superfamily
C, F	IPR009056	Cytochrome c-like domain	Domain

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A, B, C, D, E A, B, C, D, E, F	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A, B, C, D, E A, B, C, D, E, F	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Electron Transport Chain Complexes: Complex III (Cytochrome bc₁)	Cytochrome bc₁ apo structure

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.