Annotations: 6RKO

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A [auth B]	UNK_F_TYPE	e6rkoB2	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)
B [auth A]	Cyt_bd_oxida_I_1st	e6rkoA2	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: Cyt_bd_oxida_I_1st	ECOD (1.6)
B [auth A]	Cyt_bd_oxida_I_2nd	e6rkoA1	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: Cyt_bd_oxida_I_2nd	ECOD (1.6)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A [auth B]	PF02322	Cytochrome bd terminal oxidase subunit II (Cyt_bd_oxida_II)	Cytochrome bd terminal oxidase subunit II	-	Family
B [auth A]	PF01654	Cytochrome bd terminal oxidase subunit I (Cyt_bd_oxida_I)	Cytochrome bd terminal oxidase subunit I	-	Family
D [auth X]	PF08173	Membrane bound YbgT-like protein (YbgT_YccB)	Membrane bound YbgT-like protein	-	Family

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A [auth B]	Cytochrome bd-I ubiquinol oxidase subunit 2	oxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor oxidoreductase activity oxidoreductase activity, acting on diphenols and related substances as donors catalytic activity electron transfer activity cation binding ion binding binding metal ion binding small molecule binding	aerobic electron transport chain aerobic respiration cellular respiration oxidative phosphorylation energy derivation by oxidation of organic compounds cellular metabolic process electron transport chain generation of precursor metabolites and energy respiratory electron transport chain metabolic process cellular process	cell periphery plasma membrane membrane cellular anatomical entity protein-containing complex cytochrome complex catalytic complex
B [auth A]	Cytochrome bd-I ubiquinol oxidase subunit 1	oxidoreductase activity, acting on diphenols and related substances as donors, oxygen as acceptor oxidoreductase activity oxidoreductase activity, acting on diphenols and related substances as donors catalytic activity binding organic cyclic compound binding tetrapyrrole binding heme binding electron transfer activity cation binding ion binding metal ion binding small molecule binding	aerobic electron transport chain aerobic respiration cellular respiration oxidative phosphorylation energy derivation by oxidation of organic compounds cellular metabolic process electron transport chain generation of precursor metabolites and energy respiratory electron transport chain metabolic process cellular process	cell periphery plasma membrane membrane cellular anatomical entity protein-containing complex cytochrome complex catalytic complex
C [auth H]	Uncharacterized protein YnhF	-	response to decreased oxygen levels cellular response to stimulus response to stimulus cellular response to oxygen levels cellular response to hypoxia cellular response to decreased oxygen levels cellular response to chemical stimulus cellular response to stress response to hypoxia response to stress response to chemical response to oxygen levels response to abiotic stimulus cellular process	cell periphery plasma membrane membrane cellular anatomical entity protein-containing complex cytochrome complex catalytic complex
D [auth X]	Cytochrome bd-I ubiquinol oxidase subunit X	oxidoreductase activity oxidoreductase activity, acting on diphenols and related substances as donors catalytic activity	aerobic electron transport chain aerobic respiration cellular respiration oxidative phosphorylation energy derivation by oxidation of organic compounds cellular metabolic process electron transport chain generation of precursor metabolites and energy respiratory electron transport chain metabolic process cellular process	cell periphery plasma membrane membrane cellular anatomical entity outer membrane protein-containing complex cytochrome complex catalytic complex

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A [auth B]	IPR003317	Cytochrome ubiquinol oxidase subunit 2	Family
B [auth A]	IPR002585	Cytochrome ubiquinol oxidase subunit 1	Family
C [auth H]	IPR047743	Membrane protein YnhF-like	Family
D [auth X]	IPR011724	Cyd operon protein YbgT	Family
D [auth X]	IPR012994	Membrane bound YbgT-like	Family

Membrane Protein Annotation: OPM OPM Database Homepage

Chains	External Link	Type	Class	Superfamily	Family
A [auth B], B [auth A], C [auth H], D [auth X]	OPM	Transmembrane	Alpha-helical polytopic	Electron transport chain complex IV (cytochrome c oxidase)	Cytochrome BD oxidase

Membrane Protein Annotation: PDBTM PDBTM Database Homepage

Chains	External Link	Comment
A [auth B], B [auth A], C [auth H], D [auth X]	PDBTM	Annotated as membrane protein by PDBTM

Membrane Protein Annotation: MemProtMD MemProtMD Database Homepage

Chains	External Link	Comment
A [auth B], B [auth A], C [auth H], D [auth X]	MemProtMD	Annotated as membrane protein by MemProtMD

Membrane Protein Annotation: mpstruc mpstruc Database Homepage

Chains	Resource Link	Group	Subgroup	Protein
A [auth B], B [auth A], C [auth H], D [auth X]	mpstruc	TRANSMEMBRANE PROTEINS: ALPHA-HELICAL	Electron Transport Chain Complexes: Complex IV (Cytochrome C Oxidase)	Cytochrome bd-type oxidase in nanodiscs

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), 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.