Annotations: 1N2C

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

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
A	d1n2ca_	Alpha and beta proteins (a/b)	Chelatase-like	'Helical backbone' metal receptor	Nitrogenase iron-molybdenum protein	Nitrogenase iron-molybdenum protein, alpha chain	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
C	d1n2cc_	Alpha and beta proteins (a/b)	Chelatase-like	'Helical backbone' metal receptor	Nitrogenase iron-molybdenum protein	Nitrogenase iron-molybdenum protein, alpha chain	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
B	d1n2cb_	Alpha and beta proteins (a/b)	Chelatase-like	'Helical backbone' metal receptor	Nitrogenase iron-molybdenum protein	Nitrogenase iron-molybdenum protein, beta chain	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
D	d1n2cd_	Alpha and beta proteins (a/b)	Chelatase-like	'Helical backbone' metal receptor	Nitrogenase iron-molybdenum protein	Nitrogenase iron-molybdenum protein, beta chain	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
E	d1n2ce_	Alpha and beta proteins (a/b)	P-loop containing nucleoside triphosphate hydrolases	P-loop containing nucleoside triphosphate hydrolases	Nitrogenase iron protein-like	Nitrogenase iron protein	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
F	d1n2cf_	Alpha and beta proteins (a/b)	P-loop containing nucleoside triphosphate hydrolases	P-loop containing nucleoside triphosphate hydrolases	Nitrogenase iron protein-like	Nitrogenase iron protein	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
G	d1n2cg_	Alpha and beta proteins (a/b)	P-loop containing nucleoside triphosphate hydrolases	P-loop containing nucleoside triphosphate hydrolases	Nitrogenase iron protein-like	Nitrogenase iron protein	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)
H	d1n2ch_	Alpha and beta proteins (a/b)	P-loop containing nucleoside triphosphate hydrolases	P-loop containing nucleoside triphosphate hydrolases	Nitrogenase iron protein-like	Nitrogenase iron protein	(Azotobacter vinelandii ) [TaxId: 354 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	Helical backbone metal receptor	8043190	3001679	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Helical backbone metal receptor	8043190	3001679	SCOP2B (2022-06-29)
B	SCOP2B Superfamily	Helical backbone metal receptor	8043192	3001679	SCOP2B (2022-06-29)
D	SCOP2B Superfamily	Helical backbone metal receptor	8043192	3001679	SCOP2B (2022-06-29)
E	SCOP2B Superfamily	Simibi-like P-loop NTPases	8017762	3002018	SCOP2B (2022-06-29)
F	SCOP2B Superfamily	Simibi-like P-loop NTPases	8017762	3002018	SCOP2B (2022-06-29)
G	SCOP2B Superfamily	Simibi-like P-loop NTPases	8017762	3002018	SCOP2B (2022-06-29)
H	SCOP2B Superfamily	Simibi-like P-loop NTPases	8017762	3002018	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	PF00148	e1n2cA1	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148	ECOD (1.6)
C	PF00148	e1n2cC1	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148	ECOD (1.6)
B	PF00148	e1n2cB1	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148	ECOD (1.6)
B	PF00148,PF11844	e1n2cB2	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148,PF11844	ECOD (1.6)
D	PF00148	e1n2cD2	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148	ECOD (1.6)
D	PF00148,PF11844	e1n2cD1	A: a/b three-layered sandwiches	X: Flavodoxin-like	H: Class I glutamine amidotransferase-like	T: Chelatase-like	F: PF00148,PF11844	ECOD (1.6)
E	PF00142	e1n2cE1	A: a/b three-layered sandwiches	X: P-loop domains-like	H: P-loop domains-related	T: P-loop containing nucleoside triphosphate hydrolases	F: PF00142	ECOD (1.6)
F	PF00142	e1n2cF1	A: a/b three-layered sandwiches	X: P-loop domains-like	H: P-loop domains-related	T: P-loop containing nucleoside triphosphate hydrolases	F: PF00142	ECOD (1.6)
G	PF00142	e1n2cG1	A: a/b three-layered sandwiches	X: P-loop domains-like	H: P-loop domains-related	T: P-loop containing nucleoside triphosphate hydrolases	F: PF00142	ECOD (1.6)
H	PF00142	e1n2cH1	A: a/b three-layered sandwiches	X: P-loop domains-like	H: P-loop domains-related	T: P-loop containing nucleoside triphosphate hydrolases	F: PF00142	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	3.40.50.1980	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Nitrogenase molybdenum iron protein domain	CATH (4.3.0)
C	3.40.50.1980	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Nitrogenase molybdenum iron protein domain	CATH (4.3.0)
B	3.40.50.1980	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Nitrogenase molybdenum iron protein domain	CATH (4.3.0)
B	1.20.89.10	Mainly Alpha	Up-down Bundle	Nitrogenase Molybdenum-iron Protein, subunit B	domain 4	CATH (4.3.0)
D	3.40.50.1980	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Nitrogenase molybdenum iron protein domain	CATH (4.3.0)
D	1.20.89.10	Mainly Alpha	Up-down Bundle	Nitrogenase Molybdenum-iron Protein, subunit B	domain 4	CATH (4.3.0)
E	3.40.50.300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	P-loop containing nucleotide triphosphate hydrolases	CATH (4.3.0)
F	3.40.50.300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	P-loop containing nucleotide triphosphate hydrolases	CATH (4.3.0)
G	3.40.50.300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	P-loop containing nucleotide triphosphate hydrolases	CATH (4.3.0)
H	3.40.50.300	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	P-loop containing nucleotide triphosphate hydrolases	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A, C	PF00148	Nitrogenase component 1 type Oxidoreductase (Oxidored_nitro)	Nitrogenase component 1 type Oxidoreductase	-	Domain
B, D	PF11844	Domain of unknown function (DUF3364) (DUF3364)	Domain of unknown function (DUF3364)	-	Family
B, D	PF00148	Nitrogenase component 1 type Oxidoreductase (Oxidored_nitro)	Nitrogenase component 1 type Oxidoreductase	-	Domain
E, F, G, H	PF00142	4Fe-4S iron sulfur cluster binding proteins, NifH/frxC family (Fer4_NifH)	4Fe-4S iron sulfur cluster binding proteins, NifH/frxC family	-	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A, C	NITROGENASE MOLYBDENUM-IRON PROTEIN	binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding ribonucleotide binding small molecule binding iron-sulfur cluster binding metal cluster binding oxidoreductase activity oxidoreductase activity, acting on iron-sulfur proteins as donors catalytic activity carbonyl sulfide nitrogenase activity oxidoreductase activity, acting on iron-sulfur proteins as donors, dinitrogen as acceptor cation binding metal ion binding nitrogenase activity	nitrogen cycle metabolic process metabolic process nitrogen fixation	protein-containing complex molybdenum-iron nitrogenase complex catalytic complex nitrogenase complex oxidoreductase complex intracellular protein-containing complex
B, D	NITROGENASE MOLYBDENUM-IRON PROTEIN	binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding ribonucleotide binding small molecule binding iron-sulfur cluster binding metal cluster binding oxidoreductase activity oxidoreductase activity, acting on iron-sulfur proteins as donors catalytic activity carbonyl sulfide nitrogenase activity oxidoreductase activity, acting on iron-sulfur proteins as donors, dinitrogen as acceptor cation binding metal ion binding nitrogenase activity	nitrogen cycle metabolic process metabolic process nitrogen fixation	protein-containing complex molybdenum-iron nitrogenase complex catalytic complex nitrogenase complex oxidoreductase complex intracellular protein-containing complex
E, F, G, H	NITROGENASE IRON PROTEIN	binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding binding adenyl ribonucleotide binding nucleotide binding purine ribonucleotide binding purine ribonucleoside triphosphate binding nucleoside phosphate binding ion binding purine nucleotide binding organic cyclic compound binding anion binding adenyl nucleotide binding ATP binding heterocyclic compound binding carbohydrate derivative binding ribonucleotide binding small molecule binding oxidoreductase activity oxidoreductase activity, acting on iron-sulfur proteins as donors catalytic activity carbonyl sulfide nitrogenase activity oxidoreductase activity, acting on iron-sulfur proteins as donors, dinitrogen as acceptor iron-sulfur cluster binding 4 iron, 4 sulfur cluster binding metal cluster binding cation binding metal ion binding nitrogenase activity	nitrogen cycle metabolic process metabolic process nitrogen fixation	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A, C	IPR000510	Nitrogenase/oxidoreductase, component 1	Domain
A, C	IPR005972	Nitrogenase molybdenum-iron protein alpha chain	Family
A, C	IPR000318	Nitrogenase component 1, conserved site	Conserved Site
A, C	IPR010143	Nitrogenase component 1, alpha chain	Family
B, D	IPR000510	Nitrogenase/oxidoreductase, component 1	Domain
B, D	IPR005976	Nitrogenase molybdenum-iron protein beta chain	Family
B, D	IPR000318	Nitrogenase component 1, conserved site	Conserved Site
B, D	IPR024564	Nitrogenase molybdenum-iron protein beta chain, N-terminal	Domain
E, F, G, H	IPR030655	NifH/chlL conserved site	Conserved Site
E, F, G, H	IPR000392	NifH/frxC family	Family
E, F, G, H	IPR005977	Nitrogenase iron protein NifH	Family
E, F, G, H	IPR027417	P-loop containing nucleoside triphosphate hydrolase	Homologous Superfamily

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

Chains	Enzyme Name	Description	Catalytic Residues
A, B, E, F	nitrogenase M-CSA #212	The nitrogenase complex from Azotobacter vinelandii catalyses the reduction of atmospheric nitrogen to ammonia, coupled to the hydrolysis of ATP and the oxidation of ferrodoxin. It is composed of two enzyme components: the Fe protein and the MoFe protein. The Fe protein catalyses the hydrolysis of ATP and consequently transfers electron to the MoFe protein. The MoFe protein contains the FeMo-cofactor which is composed of molybdenum, a [7Fe-9S] cluster, and homocitrate, and the P-cluster which is composed of a [8Fe-7S] cluster. The reducing electrons ultimately come from an external electron donor such as ferredoxin, through the Fe protein to the FeMo-cofactor [PMID:17614310, PMID:14551236]. The complex is formed as a heterotetramer of the FeMo protein, with one homodimer of Fe protein associated with each of the two alpha-beta subunits. The FeMo protein contains the FeMo-cofactor which contains a Fe7MoS9-homocitrate cofactor (FeMo-co) which is thought to contain a nitrogen atom, and the P-cluster containing an [8Fe-7S] cluster. The Fe protein contains a [4Fe-4S] cubane cluster. Nitrogenase is very biologically important because it reduces inert dinitrogen into a form which organisms can use in synthesis. Only a small subset of organisms can catalyse this reaction while all organisms require reduced nitrogen. This reaction is of industrial interest because enzymatic nitrogen fixation occurs under very mild conditions, while the industrial Haber-Bosch process must be run at high temperatures and pressures. It should be noted that the mechanism of this enzyme is still very unclear and that the exact atoms in the FeMo-cofactor involved are unknown. However, it is known that the Fe2, S2B, Fe6, S3b, Fe7, S5A, Fe3 and S2A make up the reactive face of the cofactor [PMID:17614310].	Defined by 10 residues: CYS:A-61 [auth A-62]ALA:A-64 [auth A-65]ARG:A-95 [auth A-96]HIS:A-194 [auth A-195]CYS:B-152 [auth B-153]VAL:B-156 [auth B-157]LYS:E-10ASP:E-129LYS:F-15LYS:F-41 \| Explore in 3D: M-CSA Motif Definition Search M-CSA Motif EC: 1.18.6.1 (PDB Primary Data) Search M-CSA Motif + EC 1.18.6.1

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