ID   NIFK_METTL              Reviewed;          79 AA.
AC   P20622;
DT   01-FEB-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 1.
DT   03-AUG-2022, entry version 74.
DE   RecName: Full=Nitrogenase molybdenum-iron protein beta chain;
DE            EC=1.18.6.1;
DE   AltName: Full=Dinitrogenase;
DE   AltName: Full=Nitrogenase component I;
DE   Flags: Fragment;
GN   Name=nifK;
OS   Methanothermococcus thermolithotrophicus (Methanococcus
OS   thermolithotrophicus).
OC   Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales;
OC   Methanococcaceae; Methanothermococcus.
OX   NCBI_TaxID=2186;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=2503679; DOI=10.1111/j.1365-2958.1989.tb00200.x;
RA   Souillard N., Sibold L.;
RT   "Primary structure, functional organization and expression of nitrogenase
RT   structural genes of the thermophilic archaebacterium Methanococcus
RT   thermolithotrophicus.";
RL   Mol. Microbiol. 3:541-551(1989).
CC   -!- FUNCTION: This molybdenum-iron protein is part of the nitrogenase
CC       complex that catalyzes the key enzymatic reactions in nitrogen
CC       fixation.
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=[8Fe-7S] cluster; Xref=ChEBI:CHEBI:21143; Evidence={ECO:0000250};
CC       Note=Binds 1 [8Fe-7S] cluster per heterodimer. {ECO:0000250};
CC   -!- SUBUNIT: Tetramer of two alpha and two beta chains. Forms complex with
CC       the iron protein (nitrogenase component 2).
CC   -!- SIMILARITY: Belongs to the NifD/NifK/NifE/NifN family. {ECO:0000305}.
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DR   EMBL; X13830; CAA32059.1; -; Genomic_DNA.
DR   PIR; S06988; S06988.
DR   AlphaFoldDB; P20622; -.
DR   SMR; P20622; -.
DR   GO; GO:0005524; F:ATP binding; IEA:UniProtKB-KW.
DR   GO; GO:0018697; F:carbonyl sulfide nitrogenase activity; IEA:UniProtKB-EC.
DR   GO; GO:0051536; F:iron-sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016163; F:nitrogenase activity; IEA:UniProtKB-EC.
DR   GO; GO:0009399; P:nitrogen fixation; IEA:UniProtKB-KW.
DR   InterPro; IPR000510; Nase/OxRdtase_comp1.
DR   Pfam; PF00148; Oxidored_nitro; 1.
PE   3: Inferred from homology;
KW   ATP-binding; Iron; Iron-sulfur; Metal-binding; Nitrogen fixation;
KW   Nucleotide-binding; Oxidoreductase.
FT   CHAIN           1..>79
FT                   /note="Nitrogenase molybdenum-iron protein beta chain"
FT                   /id="PRO_0000153106"
FT   BINDING         26
FT                   /ligand="[8Fe-7S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:21143"
FT                   /ligand_note="ligand shared with alpha chain"
FT                   /evidence="ECO:0000250"
FT   BINDING         51
FT                   /ligand="[8Fe-7S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:21143"
FT                   /ligand_note="ligand shared with alpha chain"
FT                   /evidence="ECO:0000250"
FT   NON_TER         79
SQ   SEQUENCE   79 AA;  8701 MW;  692DCD3C8E119D2D CRC64;
     MSEVNAGEIC YVKKQRKGTI NPNKICQPIG AMWATVGVKG TIPFVQGSQG CTTYVRYAFN
     RHFREPVSIA TASFHEHAA