AC   MF_00533;
DC   Protein; auto
TR   HAMAP; MF_00533; -; 1; level=0
XX
Names: NifH
XX
ID   NIFH
DE   RecName: Full=Nitrogenase iron protein;
DE            EC=1.18.6.1;
DE   AltName: Full=Nitrogenase Fe protein;
DE   AltName: Full=Nitrogenase component II;
DE   AltName: Full=Nitrogenase reductase;
GN   Name=nifH;
XX
CC   -!- FUNCTION: The key enzymatic reactions in nitrogen fixation are
CC       catalyzed by the nitrogenase complex, which has 2 components: the iron
CC       protein and the molybdenum-iron protein.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=16 ATP + 16 H2O + N2 + 8 reduced [2Fe-2S]-[ferredoxin] = 16
CC         ADP + 6 H(+) + H2 + 2 NH4(+) + 8 oxidized [2Fe-2S]-[ferredoxin] + 16
CC         phosphate; Xref=Rhea:RHEA:21448, Rhea:RHEA-COMP:10000, Rhea:RHEA-
CC         COMP:10001, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:17997,
CC         ChEBI:CHEBI:18276, ChEBI:CHEBI:28938, ChEBI:CHEBI:30616,
CC         ChEBI:CHEBI:33737, ChEBI:CHEBI:33738, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:456216; EC=1.18.6.1;
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC       Note=Binds 1 [4Fe-4S] cluster per dimer.;
CC   -!- SUBUNIT: Homodimer.
case <FT:4>
CC   -!- PTM: The reversible ADP-ribosylation of #{Arg-101} inactivates the
CC       nitrogenase reductase and regulates nitrogenase activity.
end case
CC   -!- SIMILARITY: Belongs to the NifH/BchL/ChlL family.
XX
DR   Pfam; PF00142; Fer4_NifH; 1; trigger=no
DR   PIRSF; PIRSF000363; Nitrogenase_iron; 1; trigger=no
DR   PRINTS; PR00091; NITROGNASEII; 1; trigger=no
DR   NCBIfam; TIGR01287; NifH; 1; trigger=no
DR   PROSITE; PS00746; NIFH_FRXC_1; 1; trigger=no
DR   PROSITE; PS00692; NIFH_FRXC_2; 1; trigger=no
DR   PROSITE; PS51026; NIFH_FRXC_3; 1; trigger=no
XX
KW   Oxidoreductase
KW   Nitrogen fixation
KW   Metal-binding
KW   Iron
KW   Iron-sulfur
KW   4Fe-4S
KW   ATP-binding
KW   Nucleotide-binding
case <FT:4>
KW   ADP-ribosylation
end case
XX
GO   GO:0005524; F:ATP binding
GO   GO:0016163; F:nitrogenase activity
GO   GO:0009399; P:nitrogen fixation
XX
FT   From: NIFH1_AZOVI (P00459)
FT   BINDING         10..17
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT   Condition: G-K-G-G-I-[GA]-K-S
FT   BINDING         98
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared between dimeric partners"
FT   Condition: C
FT   BINDING         133
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared between dimeric partners"
FT   Condition: C
FT   MOD_RES         101
FT                   /note="ADP-ribosylarginine; by dinitrogenase reductase ADP-
FT                   ribosyltransferase"
FT   Condition: R
XX
Size: 263-307;
Related: MF_00355;
Template: P00459; P00456;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: in NOSS1, ANAVA, AZOC5, AZOCH, CLOPA, MASLA, METBA, METIV, METTH,
 METTL, PAEAZ, RHOCA
Plasmid: in RHIET, RHIME, SINFN
Comments: CROS5 has a divergent nifH with a 37 N-terminal extension; this sequence
 is not shown in the alignment and not used for the size range
XX
# Revision 1.47 2023/06/01
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