Annotations: 6BTM

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
F	UNK_F_TYPE	e6btmF2	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: UNK_F_TYPE	ECOD (1.6)
E	Cytochrome_CBB3	e6btmE1	A: alpha arrays	X: Cytochrome c-like	H: Cytochrome c (From Topology)	T: Cytochrome c	F: Cytochrome_CBB3	ECOD (1.6)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
F	Alternative Complex III subunit F	-	-	cellular anatomical structure membrane
E	Alternative Complex III subunit E	binding tetrapyrrole binding heme binding electron transfer activity cation binding ion binding metal ion binding small molecule binding	-	-
D	Alternative Complex III subunit D	-	-	cellular anatomical structure membrane
C	Alternative Complex III subunit C	-	-	cell periphery cellular anatomical structure plasma membrane membrane
B	Alternative Complex III subunit B	-	-	-
A	Alternative Complex III subunit A	binding tetrapyrrole binding heme binding electron transfer activity cation binding ion binding metal ion binding small molecule binding	-	cellular anatomical structure membrane

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
E	IPR036909	Cytochrome c-like domain superfamily	Homologous Superfamily
E	IPR009056	Cytochrome c-like domain	Domain
D	IPR021776	Alternative complex III, ActD subunit	Family
C	IPR005614	NrfD-like	Family
B	IPR017896	4Fe-4S ferredoxin-type, iron-sulphur binding domain	Domain
B	IPR030948	TAT-variant-translocation signal domain	Domain
A	IPR020942	Class III cytochrome C	Domain
A	IPR036280	Multiheme cytochrome superfamily	Homologous Superfamily
A	IPR036909	Cytochrome c-like domain superfamily	Homologous Superfamily
A	IPR009056	Cytochrome c-like domain	Domain

Membrane Protein Annotation: OPM OPM Database Homepage

Chains	External Link	Type	Class	Superfamily	Family
A, C, D, E, F	OPM	Transmembrane	Alpha-helical polytopic	Electron transport chain complex II superfamily	Polysulfide reductase

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

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

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

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

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A, C, D, E, F	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Electron Transport Chain Complexes: Complex III (Cytochrome bc₁)	Alternative complex III (ACIII) in SMA nanodiscs

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 R01GM157729. RCSB PDB uses resources of the National Energy Research Scientific Computing Center (NERSC), a Department of Energy User Facility.