ID   RISB_SYNP6              Reviewed;         181 AA.
AC   Q5N0X6;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-2005, sequence version 1.
DT   03-AUG-2022, entry version 92.
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}; OrderedLocusNames=syc1854_d;
OS   Synechococcus sp. (strain ATCC 27144 / PCC 6301 / SAUG 1402/1) (Anacystis
OS   nidulans).
OC   Bacteria; Cyanobacteria; Synechococcales; Synechococcaceae; Synechococcus.
OX   NCBI_TaxID=269084;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 27144 / PCC 6301 / SAUG 1402/1;
RX   PubMed=17211581; DOI=10.1007/s11120-006-9122-4;
RA   Sugita C., Ogata K., Shikata M., Jikuya H., Takano J., Furumichi M.,
RA   Kanehisa M., Omata T., Sugiura M., Sugita M.;
RT   "Complete nucleotide sequence of the freshwater unicellular cyanobacterium
RT   Synechococcus elongatus PCC 6301 chromosome: gene content and
RT   organization.";
RL   Photosyn. Res. 93:55-67(2007).
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 + H(+) + 2
CC         H2O + phosphate; 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; AP008231; BAD80044.1; -; Genomic_DNA.
DR   RefSeq; WP_011244164.1; NC_006576.1.
DR   AlphaFoldDB; Q5N0X6; -.
DR   SMR; Q5N0X6; -.
DR   STRING; 269084.syc1854_d; -.
DR   EnsemblBacteria; BAD80044; BAD80044; syc1854_d.
DR   KEGG; syc:syc1854_d; -.
DR   eggNOG; COG0054; Bacteria.
DR   OMA; CQGVTQG; -.
DR   UniPathway; UPA00275; UER00404.
DR   Proteomes; UP000001175; Chromosome.
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   Gene3D; 3.40.50.960; -; 1.
DR   HAMAP; MF_00178; Lumazine_synth; 1.
DR   InterPro; IPR034964; LS.
DR   InterPro; IPR002180; LS/RS.
DR   InterPro; IPR036467; LS/RS_sf.
DR   PANTHER; PTHR21058; PTHR21058; 1.
DR   Pfam; PF00885; DMRL_synthase; 1.
DR   SUPFAM; SSF52121; SSF52121; 1.
DR   TIGRFAMs; TIGR00114; lumazine-synth; 1.
PE   3: Inferred from homology;
KW   Riboflavin biosynthesis; Transferase.
FT   CHAIN           1..181
FT                   /note="6,7-dimethyl-8-ribityllumazine synthase"
FT                   /id="PRO_1000040531"
FT   ACT_SITE        93
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         23
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         61..63
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         85..87
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         90..91
FT                   /ligand="(2S)-2-hydroxy-3-oxobutyl phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58830"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         118
FT                   /ligand="5-amino-6-(D-ribitylamino)uracil"
FT                   /ligand_id="ChEBI:CHEBI:15934"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
FT   BINDING         132
FT                   /ligand="(2S)-2-hydroxy-3-oxobutyl phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58830"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00178"
SQ   SEQUENCE   181 AA;  19333 MW;  69E580924F89074C CRC64;
     MAVFEGSFVN ASQFRLAVVI GRFNDLVCEK LLAGCQDCLK RHGVDPDPQG TQVDYAWVPG
     SFEIPLVARQ LALTGRYDAI ICLGAVIRGQ TPHFDYVASE VAKGVAATSL QTGIPIAFGV
     LTVDNLQQAL ERAGIKSNLG WNYALSALEM ASLMHQIRST TGEVPRQTLP LAAAPSNFAG
     T