ID   ANFD_RUMHU              Reviewed;         518 AA.
AC   Q46082;
DT   15-JUL-1999, integrated into UniProtKB/Swiss-Prot.
DT   20-DEC-2005, sequence version 2.
DT   03-AUG-2022, entry version 90.
DE   RecName: Full=Nitrogenase iron-iron protein alpha chain;
DE            EC=1.18.6.1;
DE   AltName: Full=Dinitrogenase 3 subunit alpha;
DE   AltName: Full=Nitrogenase component I;
GN   Name=anfD;
OS   Ruminiclostridium hungatei (Clostridium hungatei).
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Oscillospiraceae;
OC   Ruminiclostridium.
OX   NCBI_TaxID=48256;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=B3B;
RA   Chen T., Leschine S.B.;
RL   Submitted (MAY-1996) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: This iron-iron protein is part of the nitrogenase complex
CC       that catalyzes the key enzymatic reactions in nitrogen fixation. Other
CC       nitrogenase complexes utilize a molybdenum-iron protein or a vanadium-
CC       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=[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=[8Fe-9S-C-homocitryl] cluster; Xref=ChEBI:CHEBI:60504;
CC         Evidence={ECO:0000250};
CC       Note=Binds 1 [8Fe-9S-C-homocitryl] cluster per subunit. {ECO:0000250};
CC   -!- SUBUNIT: Hexamer of two alpha, two beta, and two delta chains.
CC       {ECO:0000250}.
CC   -!- MISCELLANEOUS: The structure of the 8Fe-9S-C-homocitryl cluster is
CC       assumed to be analogous to the 7Fe-Mo-9S-C-homocitryl cluster.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAB02935.1; Type=Frameshift; Evidence={ECO:0000305};
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DR   EMBL; U59415; AAB02935.1; ALT_FRAME; Genomic_DNA.
DR   AlphaFoldDB; Q46082; -.
DR   SMR; Q46082; -.
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   InterPro; IPR005974; Nase_asu.
DR   InterPro; IPR010143; Nase_comp1_asu.
DR   InterPro; IPR000318; Nase_comp1_CS.
DR   InterPro; IPR011290; Nase_Fe-Fe_asu.
DR   PANTHER; PTHR43457; PTHR43457; 1.
DR   Pfam; PF00148; Oxidored_nitro; 1.
DR   TIGRFAMs; TIGR01284; alt_nitrog_alph; 1.
DR   TIGRFAMs; TIGR01861; ANFD; 1.
DR   TIGRFAMs; TIGR01862; N2-ase-Ialpha; 1.
DR   PROSITE; PS00699; NITROGENASE_1_1; 1.
PE   3: Inferred from homology;
KW   ATP-binding; Iron; Iron-sulfur; Metal-binding; Nitrogen fixation;
KW   Nucleotide-binding; Oxidoreductase.
FT   CHAIN           1..518
FT                   /note="Nitrogenase iron-iron protein alpha chain"
FT                   /id="PRO_0000153063"
FT   BINDING         49
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         75
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         257
FT                   /ligand="[8Fe-9S-C-homocitryl] cluster"
FT                   /ligand_id="ChEBI:CHEBI:60504"
FT                   /evidence="ECO:0000250"
FT   BINDING         423
FT                   /ligand="[8Fe-9S-C-homocitryl] cluster"
FT                   /ligand_id="ChEBI:CHEBI:60504"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   518 AA;  58647 MW;  95B10456D69D02AA CRC64;
     MPHHEFECSK VIPERKKHAV IKGKGETLAD ALPQGYLNTI PGSISERGCA YCVAKHVIGT
     PMKDVIHISH GPVGCTYDTW QTKRYISDND NFQLKYTYAT DVKEKHIVFG AEKLLKQNII
     EAFKRFPQIK RMTIYQTPCT ALIGDDINAI AEEVMEEMPE VDIFVCNSPG FAGPSQSGGH
     HKINIAWINQ KVGTVEPEIT GDHVINYVGE YNIQGDQEVM VDYFKRMGIQ VLSTFTGNLS
     YDGLRAMHRA HLNVLECARS AEYICNELRV RYGIPRLDID GFGFKPLADS LRKYGMFFGI
     EDRRKAIIDE EVARWKPELD WYKERLMGKK VSVWPGGSKL WHWAHVIEEE MGLKVVSVYT
     KFGHQGDMEK GMPRCGEGTL AIDDPNELEG LEALEMLKPD IILTGKRPGE VAKKVRVPYL
     NAHAYHNGPY KGFEGWVRFA RDIYNAIYSP IHQLSGIDIT KDNAPEWGNG FRTRQMLSDG
     NLSDAVRNSE TLAQYTGGYD SVSNVREREY PAFERKVG