ID   RISA_ACTPL              Reviewed;         215 AA.
AC   P50854;
DT   01-OCT-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-1996, sequence version 1.
DT   27-MAR-2024, entry version 89.
DE   RecName: Full=Riboflavin synthase;
DE            Short=RS;
DE            EC=2.5.1.9;
GN   Name=ribE; Synonyms=ribB;
OS   Actinobacillus pleuropneumoniae (Haemophilus pleuropneumoniae).
OC   Bacteria; Pseudomonadota; Gammaproteobacteria; Pasteurellales;
OC   Pasteurellaceae; Actinobacillus.
OX   NCBI_TaxID=715;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ISU-178 / Serotype 5;
RX   PubMed=8522537; DOI=10.1128/jb.177.24.7265-7270.1995;
RA   Fuller T.E., Mulks M.H.;
RT   "Characterization of Actinobacillus pleuropneumoniae riboflavin
RT   biosynthesis genes.";
RL   J. Bacteriol. 177:7265-7270(1995).
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; U27202; AAA86523.1; -; Genomic_DNA.
DR   PIR; T50547; T50547.
DR   AlphaFoldDB; P50854; -.
DR   SMR; P50854; -.
DR   UniPathway; UPA00275; UER00405.
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   NCBIfam; TIGR00187; ribE; 1.
DR   PANTHER; PTHR21098:SF0; RIBOFLAVIN SYNTHASE; 1.
DR   PANTHER; PTHR21098; RIBOFLAVIN SYNTHASE ALPHA CHAIN; 1.
DR   Pfam; PF00677; Lum_binding; 2.
DR   PIRSF; PIRSF000498; Riboflavin_syn_A; 1.
DR   SUPFAM; SSF63380; Riboflavin synthase domain-like; 2.
DR   PROSITE; PS51177; LUMAZINE_BIND; 2.
PE   3: Inferred from homology;
KW   Repeat; Riboflavin biosynthesis; Transferase.
FT   CHAIN           1..215
FT                   /note="Riboflavin synthase"
FT                   /id="PRO_0000068156"
FT   REPEAT          1..96
FT                   /note="Lumazine-binding 1"
FT   REPEAT          97..193
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         47..49
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         61..66
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         100..102
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         135
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         144..146
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
FT   BINDING         158..163
FT                   /ligand="2,4-dihydroxypteridine"
FT                   /ligand_id="ChEBI:CHEBI:16489"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000250|UniProtKB:Q2YN92"
SQ   SEQUENCE   215 AA;  23404 MW;  D66CFB7C37CFCF5E CRC64;
     MFTGIIEEVG KIAQIHKQGE FAVVTINATK VLQDVHLGDT IAVNGVCLTV TSFSSNQFTA
     DVMSETLKRT SLGELKSNSP VNLERAMAAN GRFGGHIVSG HIDGTGEIAE ITPAHNSTWY
     RIKTSPKLMR YIIEKGSITI DGISLTVVDT DDESFRVSII PHTIKETNLG SKKIGSIVNL
     ENDIVGKYIE QFLLKKPADE PKSNLSLDFL KQAGF
//