ID   NIFD_METBA              Reviewed;         532 AA.
AC   P55170;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   03-AUG-2022, entry version 83.
DE   RecName: Full=Nitrogenase molybdenum-iron protein alpha chain;
DE            EC=1.18.6.1;
DE   AltName: Full=Dinitrogenase;
DE   AltName: Full=Nitrogenase component I;
GN   Name=nifD2;
OS   Methanosarcina barkeri.
OC   Archaea; Euryarchaeota; Stenosarchaea group; Methanomicrobia;
OC   Methanosarcinales; Methanosarcinaceae; Methanosarcina.
OX   NCBI_TaxID=2208;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ATCC 43241 / DSM 1538 / 227;
RX   PubMed=7961410; DOI=10.1128/jb.176.21.6590-6598.1994;
RA   Chien Y.-T., Zinder S.H.;
RT   "Cloning, DNA sequencing, and characterization of a nifD-homologous gene
RT   from the archaeon Methanosarcina barkeri 227 which resembles nifD1 from the
RT   eubacterium Clostridium pasteurianum.";
RL   J. Bacteriol. 176:6590-6598(1994).
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   -!- COFACTOR:
CC       Name=[7Fe-Mo-9S-C-homocitryl] cluster; Xref=ChEBI:CHEBI:30409;
CC         Evidence={ECO:0000250};
CC       Note=Binds 1 [7Fe-Mo-9S-C-homocitryl] cluster per subunit.
CC       {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; U11291; AAA65880.1; -; Genomic_DNA.
DR   AlphaFoldDB; P55170; -.
DR   SMR; P55170; -.
DR   PRIDE; P55170; -.
DR   GO; GO:0016612; C:molybdenum-iron nitrogenase complex; IEA:InterPro.
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   CDD; cd01976; Nitrogenase_MoFe_alpha; 1.
DR   InterPro; IPR000510; Nase/OxRdtase_comp1.
DR   InterPro; IPR010143; Nase_comp1_asu.
DR   InterPro; IPR000318; Nase_comp1_CS.
DR   InterPro; IPR005972; Nase_Mo-Fe_asu.
DR   PANTHER; PTHR43457; PTHR43457; 1.
DR   Pfam; PF00148; Oxidored_nitro; 1.
DR   TIGRFAMs; TIGR01862; N2-ase-Ialpha; 1.
DR   TIGRFAMs; TIGR01282; nifD; 1.
DR   PROSITE; PS00699; NITROGENASE_1_1; 1.
DR   PROSITE; PS00090; NITROGENASE_1_2; 1.
PE   3: Inferred from homology;
KW   ATP-binding; Iron; Iron-sulfur; Metal-binding; Molybdenum;
KW   Nitrogen fixation; Nucleotide-binding; Oxidoreductase.
FT   CHAIN           1..532
FT                   /note="Nitrogenase molybdenum-iron protein alpha chain"
FT                   /id="PRO_0000153071"
FT   BINDING         62
FT                   /ligand="[8Fe-7S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:21143"
FT                   /ligand_note="ligand shared with beta chain"
FT                   /evidence="ECO:0000250"
FT   BINDING         88
FT                   /ligand="[8Fe-7S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:21143"
FT                   /ligand_note="ligand shared with beta chain"
FT                   /evidence="ECO:0000250"
FT   BINDING         153
FT                   /ligand="[8Fe-7S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:21143"
FT                   /ligand_note="ligand shared with beta chain"
FT                   /evidence="ECO:0000250"
FT   BINDING         271
FT                   /ligand="[7Fe-Mo-9S-C-homocitryl] cluster"
FT                   /ligand_id="ChEBI:CHEBI:30409"
FT                   /evidence="ECO:0000250"
FT   BINDING         489
FT                   /ligand="[7Fe-Mo-9S-C-homocitryl] cluster"
FT                   /ligand_id="ChEBI:CHEBI:30409"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   532 AA;  60291 MW;  698BAC4883C8845B CRC64;
     MGAEIDSRIE DEQKLVDDML KVLPEKAARN RRKHIVVRNC STEQHIEADD KVIPGILTNR
     GCAFAGTKGV VFGPIKDMVH LVHGPIGCAF YTWGTRRNFA KAEEGGDNFM NYCVCTDMKE
     TDIVFGGEKK LKKAIDEVVK IFHPEAITIC ATCPVGLIGD DIESVAREAE KEHGIKVIPA
     RCEGYRGVSQ SAGHHIASNA LMEHLIGTEE IKSPTPFDIN VFGEYNIGGD LWEVKPIFEK
     IGYRIVSSLT GDGSFHRISQ AHQAKLSILV CHRSINYTNR MMEEKYGVPW LKVNYIGTKG
     TEKLLRKMAE FFDDPELTRK TEEVIAEEKA KYAEDIEKYR KKLKGKTAFI YAGGSRSHHY
     INLFEELGMK VIAAGYQFAH RDDYEGRQII PQIKEKALGS ILEDVHYERD ENVKPTVSPE
     RIEELKTKIG LMDYKGLFPD AEDGTIVIDD LNHHETEVLV KTLKPDIFCS GIKDKYWAQK
     PWSPSRQIHS YDYSGRYTGF SGVLNFARDI DMALHSPTWK FIRPPWKAEN VE