ID   NIFH_RHORU              Reviewed;         295 AA.
AC   P22921;
DT   01-AUG-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1991, sequence version 1.
DT   03-AUG-2022, entry version 110.
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;
OS   Rhodospirillum rubrum.
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Rhodospirillales;
OC   Rhodospirillaceae; Rhodospirillum.
OX   NCBI_TaxID=1085;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1979299; DOI=10.1016/0378-1119(90)90426-r;
RA   Lehman L.J., Fitzmaurice W.P., Roberts G.P.;
RT   "The cloning and functional characterization of the nifH gene of
RT   Rhodospirillum rubrum.";
RL   Gene 95:143-147(1990).
RN   [2]
RP   PROTEIN SEQUENCE OF 101-104, IDENTIFICATION BY MASS SPECTROMETRY, AND
RP   ADP-RIBOSYLATION AT ARG-102.
RX   PubMed=3923473; DOI=10.1073/pnas.82.10.3173;
RA   Pope M.R., Murrell S.A., Ludden P.W.;
RT   "Covalent modification of the iron protein of nitrogenase from
RT   Rhodospirillum rubrum by adenosine diphosphoribosylation of a specific
RT   arginine residue.";
RL   Proc. Natl. Acad. Sci. U.S.A. 82:3173-3177(1985).
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.
CC   -!- PTM: The reversible ADP-ribosylation of Arg-102 inactivates the
CC       nitrogenase reductase and regulates nitrogenase activity.
CC   -!- SIMILARITY: Belongs to the NifH/BchL/ChlL family. {ECO:0000305}.
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DR   EMBL; M33774; AAA26463.1; -; Genomic_DNA.
DR   PIR; JW0039; JW0039.
DR   RefSeq; WP_011388765.1; NZ_NRSC01000036.1.
DR   AlphaFoldDB; P22921; -.
DR   SMR; P22921; -.
DR   OMA; YVCDYYL; -.
DR   GO; GO:0016610; C:nitrogenase complex; IMP:CACAO.
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   1: Evidence at protein level;
KW   4Fe-4S; ADP-ribosylation; ATP-binding; Direct protein sequencing; Iron;
KW   Iron-sulfur; Metal-binding; Nitrogen fixation; Nucleotide-binding;
KW   Oxidoreductase.
FT   CHAIN           1..295
FT                   /note="Nitrogenase iron protein"
FT                   /id="PRO_0000139529"
FT   BINDING         11..18
FT                   /ligand="ATP"
FT                   /ligand_id="ChEBI:CHEBI:30616"
FT                   /evidence="ECO:0000255"
FT   BINDING         99
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         133
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         102
FT                   /note="ADP-ribosylarginine; by dinitrogenase reductase ADP-
FT                   ribosyltransferase"
FT                   /evidence="ECO:0000269|PubMed:3923473"
SQ   SEQUENCE   295 AA;  31642 MW;  98E496665719B6EB CRC64;
     MSALRQIAFY GKGGIGKSTT SQNTLAALVE MGQRILIVGC DPKADSTRLI LNTKLQDTVL
     HLAAEAGSVE DLDVADVVKI GYKGIKCTES GGPEPGVGCA GRGVITAINF LEENGAYDDL
     DYVSYDVLGD VVCGGFAMPI RENKAQEIYI VMSGEMMALY AANNIAKGIL KYAHTGGVRL
     GGLICNERQT DKEVELAEAL AGRLGCRLIH FVPRDNGVQH AELRRQTVIQ YAPDSKQAGE
     YRTLATKIHN NSGQGVVPTP ITMEDLEEML MEFGIMKSDE EALAELEAKE SAAAN