Annotations: 1FGJ

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1fgja_	All alpha proteins	Multiheme cytochromes	Multiheme cytochromes	Di-heme elbow motif	Hydroxylamine oxidoreductase, HAO	(Nitrosomonas europaea ) [TaxId: 915 ],	SCOPe (2.08)
B	d1fgjb_	All alpha proteins	Multiheme cytochromes	Multiheme cytochromes	Di-heme elbow motif	Hydroxylamine oxidoreductase, HAO	(Nitrosomonas europaea ) [TaxId: 915 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2 Family	HAO/Nir-like	8003664	4000358	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Di-heme elbow motif	8003665	3000145	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Di-heme elbow motif	8003666	3000145	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	Di-heme elbow motif	8003667	3000145	SCOP2 (2022-06-29)
A	SCOP2 Superfamily	HAO C-terminal domain-like	8056472	3002349	SCOP2 (2022-06-29)
B	SCOP2B Superfamily	Di-heme elbow motif	8003667	3000145	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Di-heme elbow motif	8003666	3000145	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Di-heme elbow motif	8003665	3000145	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	HAO C-terminal domain-like	8056472	3002349	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
A	Multi-haem_cyto	e1fgjA1	A: few secondary structure elements	X: Multiheme cytochromes	H: Di-heme elbow motif (From Topology)	T: Di-heme elbow motif	F: Multi-haem_cyto	ECOD (1.6)
B	Multi-haem_cyto	e1fgjB1	A: few secondary structure elements	X: Multiheme cytochromes	H: Di-heme elbow motif (From Topology)	T: Di-heme elbow motif	F: Multi-haem_cyto	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	1.10.780.10	Mainly Alpha	Orthogonal Bundle	Hydroxylamine Oxidoreductase	Chain A, domain 1	CATH (4.3.0)
A	1.20.850.10	Mainly Alpha	Up-down Bundle	Hydroxylamine Oxidoreductase	Chain A, domain 2	CATH (4.3.0)
B	1.10.780.10	Mainly Alpha	Orthogonal Bundle	Hydroxylamine Oxidoreductase	Chain A, domain 1	CATH (4.3.0)
B	1.20.850.10	Mainly Alpha	Up-down Bundle	Hydroxylamine Oxidoreductase	Chain A, domain 2	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, B	PF13447	Seven times multi-haem cytochrome CxxCH (Multi-haem_cyto)	Seven times multi-haem cytochrome CxxCH	This domain carries up to seven CxxCH repeated sequence motifs, characteristic of multi-haem cytochromes.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, B	HYDROXYLAMINE OXIDOREDUCTASE	oxidoreductase activity catalytic activity oxidoreductase activity, acting on the CH-NH group of donors, NAD or NADP as acceptor oxidoreductase activity, acting on the CH-NH group of donors hydroxylamine oxidoreductase activity oxidoreductase activity, acting on other nitrogenous compounds as donors oxidoreductase activity, acting on other nitrogenous compounds as donors, oxygen as acceptor hydroxylamine oxidase activity binding organic cyclic compound binding tetrapyrrole binding heme binding cation binding ion binding oxidoreductase activity catalytic activity oxidoreductase activity, acting on the CH-NH group of donors, NAD or NADP as acceptor oxidoreductase activity, acting on the CH-NH group of donors hydroxylamine oxidoreductase activity oxidoreductase activity, acting on other nitrogenous compounds as donors oxidoreductase activity, acting on other nitrogenous compounds as donors, oxygen as acceptor hydroxylamine oxidase activity binding organic cyclic compound binding tetrapyrrole binding heme binding cation binding ion binding metal ion binding small molecule binding identical protein binding protein binding	ammonia oxidation cellular respiration energy derivation by oxidation of organic compounds cellular metabolic process generation of precursor metabolites and energy energy derivation by oxidation of reduced inorganic compounds small molecule metabolic process metabolic process cellular process anaerobic respiration, using ammonium as electron donor anaerobic respiration protein-containing complex organization protein trimerization cellular component organization ammonia oxidation cellular respiration energy derivation by oxidation of organic compounds cellular metabolic process generation of precursor metabolites and energy energy derivation by oxidation of reduced inorganic compounds small molecule metabolic process metabolic process cellular process anaerobic respiration, using ammonium as electron donor anaerobic respiration protein-containing complex organization protein trimerization cellular component organization cellular component biogenesis cellular component assembly protein homotrimerization protein complex oligomerization protein-containing complex assembly protein homooligomerization cellular component organization or biogenesis	membrane-bounded organelle intracellular organelle intracellular anatomical structure anammoxosome organelle cytoplasm cellular anatomical entity intracellular membrane-bounded organelle

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, B	IPR036280	Multiheme cytochrome superfamily	Homologous Superfamily
A, B	IPR012138	Hydroxylamine oxidase	Family

Structure Motif Annotation: Mechanism and Catalytic Site Atlas M-CSA Database Homepage

Chains	Enzyme Name	Description	Catalytic Residues
A	hydroxylamine oxidase M-CSA #581	Hydroxylamine oxioreductase catalyses the conversion of hydroxylamines to nitrite. This is the second step in the respiratory system of nitrifying chemoautotrophic bacteria. Ammonia mono-oxygenase produces hydroxylamine which is reduced by hydroxylamine oxioreductase to product electrons which feed into an electron transport chain to produce energy. The enzyme employs 24 haem groups across three sub units which interact in a uniquely complicated electron transport chain.	Defined by 5 residues: HIS:A-233ASP:A-267HIS:A-268TYR:A-334TYR:A_3-467 \| Explore in 3D: M-CSA Motif Definition Search M-CSA Motif EC: 1.7.3.4 (PDB Primary Data) Search M-CSA Motif + EC 1.7.3.4

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.