ID   RISA_BUCAI              Reviewed;         208 AA.
AC   P57212;
DT   01-DEC-2000, integrated into UniProtKB/Swiss-Prot.
DT   01-DEC-2000, sequence version 1.
DT   03-AUG-2022, entry version 108.
DE   RecName: Full=Riboflavin synthase;
DE            Short=RS;
DE            EC=2.5.1.9;
GN   Name=ribE; OrderedLocusNames=BU112;
OS   Buchnera aphidicola subsp. Acyrthosiphon pisum (strain APS) (Acyrthosiphon
OS   pisum symbiotic bacterium).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Erwiniaceae; Buchnera.
OX   NCBI_TaxID=107806;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=APS;
RX   PubMed=10993077; DOI=10.1038/35024074;
RA   Shigenobu S., Watanabe H., Hattori M., Sakaki Y., Ishikawa H.;
RT   "Genome sequence of the endocellular bacterial symbiont of aphids Buchnera
RT   sp. APS.";
RL   Nature 407:81-86(2000).
CC   -!- FUNCTION: Catalyzes the dismutation of two molecules of 6,7-dimethyl-8-
CC       ribityllumazine, resulting in the formation of riboflavin and 5-amino-
CC       6-(D-ribitylamino)uracil. {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 6,7-dimethyl-8-(1-D-ribityl)lumazine + H(+) = 5-amino-6-(D-
CC         ribitylamino)uracil + riboflavin; Xref=Rhea:RHEA:20772,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:15934, ChEBI:CHEBI:57986,
CC         ChEBI:CHEBI:58201; EC=2.5.1.9;
CC   -!- PATHWAY: Cofactor biosynthesis; riboflavin biosynthesis; riboflavin
CC       from 2-hydroxy-3-oxobutyl phosphate and 5-amino-6-(D-
CC       ribitylamino)uracil: step 2/2.
CC   -!- SUBUNIT: Homotrimer. {ECO:0000250}.
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DR   EMBL; BA000003; BAB12830.1; -; Genomic_DNA.
DR   RefSeq; NP_239944.1; NC_002528.1.
DR   RefSeq; WP_010895951.1; NC_002528.1.
DR   AlphaFoldDB; P57212; -.
DR   SMR; P57212; -.
DR   STRING; 107806.10038795; -.
DR   EnsemblBacteria; BAB12830; BAB12830; BAB12830.
DR   KEGG; buc:BU112; -.
DR   PATRIC; fig|107806.10.peg.119; -.
DR   eggNOG; COG0307; Bacteria.
DR   HOGENOM; CLU_034388_0_1_6; -.
DR   OMA; HILSGHV; -.
DR   UniPathway; UPA00275; UER00405.
DR   Proteomes; UP000001806; Chromosome.
DR   GO; GO:0004746; F:riboflavin synthase activity; IEA:UniProtKB-EC.
DR   GO; GO:0009231; P:riboflavin biosynthetic process; IEA:UniProtKB-UniPathway.
DR   CDD; cd00402; Riboflavin_synthase_like; 1.
DR   Gene3D; 2.40.30.20; -; 2.
DR   InterPro; IPR023366; ATP_synth_asu-like_sf.
DR   InterPro; IPR001783; Lumazine-bd.
DR   InterPro; IPR026017; Lumazine-bd_dom.
DR   InterPro; IPR017938; Riboflavin_synthase-like_b-brl.
DR   PANTHER; PTHR21098; PTHR21098; 1.
DR   Pfam; PF00677; Lum_binding; 2.
DR   PIRSF; PIRSF000498; Riboflavin_syn_A; 1.
DR   SUPFAM; SSF63380; SSF63380; 2.
DR   TIGRFAMs; TIGR00187; ribE; 1.
DR   PROSITE; PS51177; LUMAZINE_BIND; 2.
PE   3: Inferred from homology;
KW   Reference proteome; Repeat; Riboflavin biosynthesis; Transferase.
FT   CHAIN           1..208
FT                   /note="Riboflavin synthase"
FT                   /id="PRO_0000068160"
FT   REPEAT          1..97
FT                   /note="Lumazine-binding 1"
FT   REPEAT          98..195
FT                   /note="Lumazine-binding 2"
FT   BINDING         4..6
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         48..50
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared between two trimeric partners"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         62..67
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared between two trimeric partners"
FT                   /evidence="ECO:0000250|UniProtKB:P0AFU8"
FT   BINDING         101..103
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared between two trimeric partners"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         137
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="2"
FT                   /ligand_note="ligand shared between two trimeric partners"
FT                   /note="in other chain"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         146..148
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         160..165
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
SQ   SEQUENCE   208 AA;  23505 MW;  7CCE3272CF54BA5B CRC64;
     MFTGIINGTA TIVYIEKKKK KYRYTVELPS NLSKNLKLGD SISHNGCCLT VKLINNSFII
     CDVIQETLKS TNLGILNIGD SINIERSIKY GDEIGGHIIS GHVMNTAEIS KMSKSDNNCV
     IWLKMNNMSL MKYIFYKGFI CVDGISLTVN DIIKNEFCVN IIPYTFLFTT IKDKKNGSLV
     NIEIDFYTQT IVDTTERLIN NNLKSLYD