ID   BLUB_RHOCB              Reviewed;         207 AA.
AC   D5AV14; O68092; Q52685;
DT   28-JUN-2011, integrated into UniProtKB/Swiss-Prot.
DT   15-JUN-2010, sequence version 1.
DT   03-AUG-2022, entry version 57.
DE   RecName: Full=5,6-dimethylbenzimidazole synthase;
DE            Short=DMB synthase;
DE            EC=1.13.11.79;
GN   Name=bluB; OrderedLocusNames=RCAP_rcc02052;
OS   Rhodobacter capsulatus (strain ATCC BAA-309 / NBRC 16581 / SB1003).
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Rhodobacterales;
OC   Rhodobacteraceae; Rhodobacter.
OX   NCBI_TaxID=272942;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ATCC BAA-309 / NBRC 16581 / SB1003;
RX   PubMed=9256491; DOI=10.1073/pnas.94.17.9384;
RA   Vlcek C., Paces V., Maltsev N., Paces J., Haselkorn R., Fonstein M.;
RT   "Sequence of a 189-kb segment of the chromosome of Rhodobacter capsulatus
RT   SB1003.";
RL   Proc. Natl. Acad. Sci. U.S.A. 94:9384-9388(1997).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-309 / NBRC 16581 / SB1003;
RX   PubMed=20418398; DOI=10.1128/jb.00366-10;
RA   Strnad H., Lapidus A., Paces J., Ulbrich P., Vlcek C., Paces V.,
RA   Haselkorn R.;
RT   "Complete genome sequence of the photosynthetic purple nonsulfur bacterium
RT   Rhodobacter capsulatus SB 1003.";
RL   J. Bacteriol. 192:3545-3546(2010).
CC   -!- FUNCTION: Involved in the biosynthesis of cobalamin (vitamin B12).
CC       Catalyzes the oxidative fragmentation and contraction of the
CC       isoalloxazine heterocycle and the cleavage of the ribityl tail of
CC       FMNH(2) to form 5,6-dimethylbenzimidazole (DMB) and D-erythrose 4-
CC       phosphate (E4P). NAD(P)H is only required initially to reduce FMN and
CC       oxygen drives the oxidative fragmentation (By similarity).
CC       {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=FMNH2 + O2 = 5,6-dimethylbenzimidazole + D-erythrose 4-
CC         phosphate + dialurate + H(+); Xref=Rhea:RHEA:27345,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:15890,
CC         ChEBI:CHEBI:16897, ChEBI:CHEBI:57618, ChEBI:CHEBI:140629;
CC         EC=1.13.11.79;
CC   -!- SUBUNIT: Homooctamer. {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the BluB family. {ECO:0000305}.
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DR   EMBL; AF010496; AAC16179.1; -; Genomic_DNA.
DR   EMBL; CP001312; ADE85796.1; -; Genomic_DNA.
DR   PIR; T03526; T03526.
DR   RefSeq; WP_013067775.1; NC_014034.1.
DR   AlphaFoldDB; D5AV14; -.
DR   SMR; D5AV14; -.
DR   STRING; 272942.RCAP_rcc02052; -.
DR   EnsemblBacteria; ADE85796; ADE85796; RCAP_rcc02052.
DR   GeneID; 31490914; -.
DR   KEGG; rcp:RCAP_rcc02052; -.
DR   eggNOG; COG0778; Bacteria.
DR   HOGENOM; CLU_070764_3_0_5; -.
DR   OMA; FMQPWDF; -.
DR   OrthoDB; 1847197at2; -.
DR   Proteomes; UP000002361; Chromosome.
DR   GO; GO:0102919; F:5,6-dimethylbenzimidazole synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0000166; F:nucleotide binding; IEA:UniProtKB-KW.
DR   GO; GO:0016705; F:oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen; ISS:UniProtKB.
DR   GO; GO:0009236; P:cobalamin biosynthetic process; ISS:UniProtKB.
DR   CDD; cd02145; BluB; 1.
DR   Gene3D; 3.40.109.10; -; 1.
DR   InterPro; IPR012825; BluB.
DR   InterPro; IPR029479; Nitroreductase.
DR   InterPro; IPR000415; Nitroreductase-like.
DR   Pfam; PF00881; Nitroreductase; 1.
DR   SUPFAM; SSF55469; SSF55469; 1.
DR   TIGRFAMs; TIGR02476; BluB; 1.
PE   3: Inferred from homology;
KW   Cobalamin biosynthesis; Flavoprotein; FMN; NAD; NADP; Nucleotide-binding;
KW   Oxidoreductase; Reference proteome.
FT   CHAIN           1..207
FT                   /note="5,6-dimethylbenzimidazole synthase"
FT                   /id="PRO_0000409928"
FT   BINDING         18..22
FT                   /ligand="FMN"
FT                   /ligand_id="ChEBI:CHEBI:58210"
FT                   /evidence="ECO:0000250"
FT   BINDING         46
FT                   /ligand="FMN"
FT                   /ligand_id="ChEBI:CHEBI:58210"
FT                   /evidence="ECO:0000250"
FT   BINDING         95
FT                   /ligand="FMN"
FT                   /ligand_id="ChEBI:CHEBI:58210"
FT                   /evidence="ECO:0000250"
FT   BINDING         154
FT                   /ligand="FMN"
FT                   /ligand_id="ChEBI:CHEBI:58210"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   207 AA;  23059 MW;  02C6AE7A0D33C989 CRC64;
     MNFEQTHRDA LTEVLRWRRD VRHFRPDPID EAVIDRLRAV MDMAPSVGNA RPWRVIRVDS
     PALRAEVLAN FNAARAAAGS AYAGEQAEAY ATLKLQGIDQ APLQLAVFTH RDPAAGHGLG
     RASMPVTLQQ STAMAIHTLW LAARAENLGL GMVSVLDPKA VERLLNAPPD WDFVAWLCIG
     VPEFTDDTPL LHRAGWQENL PTEWERR