ID   RISB_CHLPM              Reviewed;         155 AA.
AC   A4SGN3;
DT   20-MAY-2008, integrated into UniProtKB/Swiss-Prot.
DT   15-MAY-2007, sequence version 1.
DT   18-JUN-2025, entry version 94.
DE   RecName: Full=6,7-dimethyl-8-ribityllumazine synthase {ECO:0000255|HAMAP-Rule:MF_00178};
DE            Short=DMRL synthase {ECO:0000255|HAMAP-Rule:MF_00178};
DE            Short=LS {ECO:0000255|HAMAP-Rule:MF_00178};
DE            Short=Lumazine synthase {ECO:0000255|HAMAP-Rule:MF_00178};
DE            EC=2.5.1.78 {ECO:0000255|HAMAP-Rule:MF_00178};
GN   Name=ribH {ECO:0000255|HAMAP-Rule:MF_00178};
GN   OrderedLocusNames=Cvib_1632;
OS   Chlorobium phaeovibrioides (strain DSM 265 / 1930) (Prosthecochloris
OS   vibrioformis (strain DSM 265)).
OC   Bacteria; Pseudomonadati; Chlorobiota; Chlorobiia; Chlorobiales;
OC   Chlorobiaceae; Chlorobium/Pelodictyon group; Chlorobium.
OX   NCBI_TaxID=290318;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 265 / 1930;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C.,
RA   Glavina del Rio T., Hammon N., Israni S., Pitluck S., Schmutz J.,
RA   Larimer F., Land M., Hauser L., Mikhailova N., Li T., Overmann J.,
RA   Schuster S.C., Bryant D.A., Richardson P.;
RT   "Complete sequence of Prosthecochloris vibrioformis DSM 265.";
RL   Submitted (MAR-2007) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Catalyzes the formation of 6,7-dimethyl-8-ribityllumazine by
CC       condensation of 5-amino-6-(D-ribitylamino)uracil with 3,4-dihydroxy-2-
CC       butanone 4-phosphate. This is the penultimate step in the biosynthesis
CC       of riboflavin. {ECO:0000255|HAMAP-Rule:MF_00178}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(2S)-2-hydroxy-3-oxobutyl phosphate + 5-amino-6-(D-
CC         ribitylamino)uracil = 6,7-dimethyl-8-(1-D-ribityl)lumazine +
CC         phosphate + 2 H2O + H(+); Xref=Rhea:RHEA:26152, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:15934, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:58201, ChEBI:CHEBI:58830; EC=2.5.1.78;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00178};
CC   -!- PATHWAY: Cofactor biosynthesis; riboflavin biosynthesis; riboflavin
CC       from 2-hydroxy-3-oxobutyl phosphate and 5-amino-6-(D-
CC       ribitylamino)uracil: step 1/2. {ECO:0000255|HAMAP-Rule:MF_00178}.
CC   -!- SIMILARITY: Belongs to the DMRL synthase family. {ECO:0000255|HAMAP-
CC       Rule:MF_00178}.
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DR   EMBL; CP000607; ABP37642.1; -; Genomic_DNA.
DR   AlphaFoldDB; A4SGN3; -.
DR   SMR; A4SGN3; -.
DR   STRING; 290318.Cvib_1632; -.
DR   KEGG; pvi:Cvib_1632; -.
DR   eggNOG; COG0054; Bacteria.
DR   HOGENOM; CLU_089358_1_1_10; -.
DR   OrthoDB; 9809709at2; -.
DR   UniPathway; UPA00275; UER00404.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
DR   GO; GO:0009349; C:riboflavin synthase complex; IEA:InterPro.
DR   GO; GO:0000906; F:6,7-dimethyl-8-ribityllumazine synthase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0009231; P:riboflavin biosynthetic process; IEA:UniProtKB-UniRule.
DR   CDD; cd09209; Lumazine_synthase-I; 1.
DR   FunFam; 3.40.50.960:FF:000001; 6,7-dimethyl-8-ribityllumazine synthase; 1.
DR   Gene3D; 3.40.50.960; Lumazine/riboflavin synthase; 1.
DR   HAMAP; MF_00178; Lumazine_synth; 1.
DR   InterPro; IPR034964; LS.
DR   InterPro; IPR002180; LS/RS.
DR   InterPro; IPR036467; LS/RS_sf.
DR   NCBIfam; TIGR00114; lumazine-synth; 1.
DR   NCBIfam; NF000812; PRK00061.1-4; 1.
DR   PANTHER; PTHR21058:SF0; 6,7-DIMETHYL-8-RIBITYLLUMAZINE SYNTHASE; 1.
DR   PANTHER; PTHR21058; 6,7-DIMETHYL-8-RIBITYLLUMAZINE SYNTHASE DMRL SYNTHASE LUMAZINE SYNTHASE; 1.
DR   Pfam; PF00885; DMRL_synthase; 1.
DR   SUPFAM; SSF52121; Lumazine synthase; 1.
PE   3: Inferred from homology;
KW   Riboflavin biosynthesis; Transferase.
FT   CHAIN           1..155
FT                   /note="6,7-dimethyl-8-ribityllumazine synthase"
FT                   /id="PRO_1000077243"
FT   ACT_SITE        90
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         24
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         58..60
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         82..84
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         87..88
FT                   /ligand="(2S)-2-hydroxy-3-oxobutyl phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58830"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         115
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         129
FT                   /ligand="(2S)-2-hydroxy-3-oxobutyl phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58830"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
SQ   SEQUENCE   155 AA;  16430 MW;  D6DD08F8A74221B2 CRC64;
     MQIQQIEGGF GAQDARIALV VSRFNDFIGQ KLVEGAIDCI RRNGGSEENI AIYRCPGAFE
     LPMVAKKVAL TGKYDAVVTL GAIIRGSTPH FDVIAAEATK GIAQASLETG VPIAFGVLTT
     ENIEQAIERA GTKAGNKGFD AALTAIEMIN LYRAM
//