ID   NIFB_KLEOX              Reviewed;         137 AA.
AC   P56265;
DT   15-JUL-1998, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2000, sequence version 2.
DT   03-AUG-2022, entry version 75.
DE   RecName: Full=FeMo cofactor biosynthesis protein NifB;
DE            EC=4.-.-.-;
DE   AltName: Full=Nitrogenase cofactor maturase NifB;
DE   AltName: Full=Radical SAM assemblase NifB;
DE   Flags: Fragment;
GN   Name=nifB;
OS   Klebsiella oxytoca.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Klebsiella/Raoultella group; Klebsiella.
OX   NCBI_TaxID=571;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=NG13;
RX   PubMed=3027503; DOI=10.1007/bf00430436;
RA   Kim Y.-M., Ahn K.-J., Beppu T., Uozumi T.;
RT   "Nucleotide sequence of the nifLA operon of Klebsiella oxytoca NG13 and
RT   characterization of the gene products.";
RL   Mol. Gen. Genet. 205:253-259(1986).
CC   -!- FUNCTION: Involved in the biosynthesis of the iron-molybdenum cofactor
CC       (FeMo-co or M-cluster) found in the dinitrogenase enzyme of the
CC       nitrogenase complex in nitrogen-fixing microorganisms. NifB catalyzes
CC       the crucial step of radical SAM-dependent carbide insertion that occurs
CC       concomitant with the insertion of a 9th sulfur and the
CC       rearrangement/coupling of two [4Fe-4S] clusters into a [8Fe-9S-C]
CC       cluster, the precursor to the M-cluster.
CC       {ECO:0000250|UniProtKB:D5VRM1}.
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC         Evidence={ECO:0000250|UniProtKB:D5VRM1};
CC       Note=Binds 3 [4Fe-4S] clusters per monomer. One cluster is coordinated
CC       with 3 cysteines and an exchangeable S-adenosyl-L-methionine. The two
CC       others probably act as substrate. {ECO:0000250|UniProtKB:D5VRM1};
CC   -!- PATHWAY: Cofactor biosynthesis; Fe-Mo cofactor biosynthesis.
CC       {ECO:0000250|UniProtKB:D5VRM1}.
CC   -!- SIMILARITY: Belongs to the radical SAM superfamily. NifB family.
CC       {ECO:0000305}.
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DR   EMBL; D00339; BAA20957.1; -; Genomic_DNA.
DR   AlphaFoldDB; P56265; -.
DR   SMR; P56265; -.
DR   STRING; 571.MC52_26870; -.
DR   eggNOG; COG0535; Bacteria.
DR   UniPathway; UPA00782; -.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0016829; F:lyase activity; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0009399; P:nitrogen fixation; IEA:UniProtKB-KW.
DR   Gene3D; 3.20.20.70; -; 1.
DR   InterPro; IPR013785; Aldolase_TIM.
DR   InterPro; IPR000385; MoaA_NifB_PqqE_Fe-S-bd_CS.
DR   InterPro; IPR005980; Nase_CF_NifB.
DR   InterPro; IPR007197; rSAM.
DR   PANTHER; PTHR43787:SF3; PTHR43787:SF3; 1.
DR   Pfam; PF04055; Radical_SAM; 1.
DR   SFLD; SFLDS00029; Radical_SAM; 1.
DR   PROSITE; PS01305; MOAA_NIFB_PQQE; 1.
DR   PROSITE; PS51918; RADICAL_SAM; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; Iron; Iron-sulfur; Lyase; Metal-binding; Nitrogen fixation;
KW   S-adenosyl-L-methionine.
FT   CHAIN           1..>137
FT                   /note="FeMo cofactor biosynthesis protein NifB"
FT                   /id="PRO_0000153040"
FT   DOMAIN          40..>137
FT                   /note="Radical SAM core"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01266"
FT   BINDING         54
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_label="1"
FT                   /ligand_note="4Fe-4S-S-AdoMet"
FT                   /evidence="ECO:0000250|UniProtKB:P69848"
FT   BINDING         58
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_label="1"
FT                   /ligand_note="4Fe-4S-S-AdoMet"
FT                   /evidence="ECO:0000250|UniProtKB:P69848"
FT   BINDING         60
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000250|UniProtKB:P69848"
FT   BINDING         61
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /ligand_label="1"
FT                   /ligand_note="4Fe-4S-S-AdoMet"
FT                   /evidence="ECO:0000250|UniProtKB:P69848"
FT   BINDING         108
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000250|UniProtKB:P69848"
FT   NON_TER         137
SQ   SEQUENCE   137 AA;  14719 MW;  C8A8BA4385BEEADC CRC64;
     MTSCSSFSGG KACRPADDSA LTPLVADKAA AHPCYSRNGH HRFARMHLPV APACNLQCNY
     CNRKFDCSNE SRPGVSSTLL TPEQAVVKVR QVAQAIPQLS VVGIAGPGDP LANIARTFRT
     LELIREQLPD LKLCLST