ID   NIFH2_MASLA             Reviewed;         307 AA.
AC   Q47921;
DT   23-JAN-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 103.
DE   RecName: Full=Nitrogenase iron protein 2;
DE            EC=1.18.6.1;
DE   AltName: Full=Nitrogenase Fe protein 2;
DE   AltName: Full=Nitrogenase component II;
DE   AltName: Full=Nitrogenase reductase;
GN   Name=nifH2;
OS   Mastigocladus laminosus (Fischerella sp.).
OC   Bacteria; Cyanobacteria; Nostocales; Hapalosiphonaceae; Mastigocladus.
OX   NCBI_TaxID=83541;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=UTEX 1931;
RA   Luo X.-Z.J., Stevens S.E.;
RT   "Nucleotide sequences of the nifHDK, orf4, and nifH2 genes and of putative
RT   regulatory sequences from the thermophilic cyanobacterium Fischerella sp.";
RL   Submitted (FEB-1996) to the EMBL/GenBank/DDBJ databases.
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. {ECO:0000250}.
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; Evidence={ECO:0000250};
CC       Note=Binds 1 [4Fe-4S] cluster per dimer. {ECO:0000250};
CC   -!- SUBUNIT: Homodimer. {ECO:0000250}.
CC   -!- PTM: The reversible ADP-ribosylation of Arg-104 inactivates the
CC       nitrogenase reductase and regulates nitrogenase activity.
CC       {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the NifH/BchL/ChlL family. {ECO:0000305}.
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DR   EMBL; U49515; AAC64641.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q47921; -.
DR   SMR; Q47921; -.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0018697; F:carbonyl sulfide nitrogenase activity; IEA:UniProtKB-EC.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016163; F:nitrogenase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0009399; P:nitrogen fixation; IEA:UniProtKB-UniRule.
DR   Gene3D; 3.40.50.300; -; 1.
DR   HAMAP; MF_00533; NifH; 1.
DR   InterPro; IPR030655; NifH/chlL_CS.
DR   InterPro; IPR000392; NifH/frxC.
DR   InterPro; IPR005977; Nitrogenase_Fe_NifH.
DR   InterPro; IPR027417; P-loop_NTPase.
DR   PANTHER; PTHR42864; PTHR42864; 1.
DR   Pfam; PF00142; Fer4_NifH; 1.
DR   PIRSF; PIRSF000363; Nitrogenase_iron; 1.
DR   SUPFAM; SSF52540; SSF52540; 1.
DR   TIGRFAMs; TIGR01287; nifH; 1.
DR   PROSITE; PS00746; NIFH_FRXC_1; 1.
DR   PROSITE; PS00692; NIFH_FRXC_2; 1.
DR   PROSITE; PS51026; NIFH_FRXC_3; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; ADP-ribosylation; ATP-binding; Iron; Iron-sulfur; Metal-binding;
KW   Nitrogen fixation; Nucleotide-binding; Oxidoreductase.
FT   CHAIN           1..307
FT                   /note="Nitrogenase iron protein 2"
FT                   /id="PRO_0000139513"
FT   REGION          285..307
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         13..20
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255"
FT   BINDING         101
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared between dimeric partners"
FT                   /evidence="ECO:0000250"
FT   BINDING         135
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_note="ligand shared between dimeric partners"
FT                   /evidence="ECO:0000250"
FT   MOD_RES         104
FT                   /note="ADP-ribosylarginine; by dinitrogenase reductase ADP-
FT                   ribosyltransferase"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   307 AA;  33823 MW;  9845BA6FE59431E8 CRC64;
     MSDERIRQIA FYGKGGIGKS TTSQNTLAAM AEMGKRILIV GCDPKADSTR LILHCKAQTT
     VLHLAAEKGA VEDLELEEVV INGFRNIRCV ESGGPEPGVG CAGRGIITAI NFLEENGAYQ
     DLDFVSYDVL GDVVCGGFAM PIREGKAQEI YIVTSGEMMA MFAANNISRG ILKYAHSGGV
     RLGGLICNSR KTDREWDLIS ELARRISTQM IHFVPRDNIV QHAELRRMTV NEYAPDSNQA
     NEYRTLATKI IDNEFMAVPT PLEMDELEEL LIEFGILESD EQVKQLTETD KAAKESEKKQ
     EDAEGEA