ID   C7LSH6_DESBD            Unreviewed;       404 AA.
AC   C7LSH6;
DT   13-OCT-2009, integrated into UniProtKB/TrEMBL.
DT   13-OCT-2009, sequence version 1.
DT   02-SEP-2026, entry version 103.
DE   RecName: Full=Riboflavin biosynthesis protein RibBA {ECO:0000256|HAMAP-Rule:MF_01283};
DE   Includes:
DE     RecName: Full=3,4-dihydroxy-2-butanone 4-phosphate synthase {ECO:0000256|HAMAP-Rule:MF_01283};
DE              Short=DHBP synthase {ECO:0000256|HAMAP-Rule:MF_01283};
DE              EC=4.1.99.12 {ECO:0000256|HAMAP-Rule:MF_01283};
DE   Includes:
DE     RecName: Full=GTP cyclohydrolase-2 {ECO:0000256|HAMAP-Rule:MF_01283};
DE              EC=3.5.4.25 {ECO:0000256|HAMAP-Rule:MF_01283};
DE     AltName: Full=GTP cyclohydrolase II {ECO:0000256|HAMAP-Rule:MF_01283};
GN   Name=ribBA {ECO:0000256|HAMAP-Rule:MF_01283};
GN   OrderedLocusNames=Dbac_0060 {ECO:0000313|EMBL:ACU88190.1};
OS   Desulfomicrobium baculatum (strain DSM 4028 / VKM B-1378 / X)
OS   (Desulfovibrio baculatus).
OC   Bacteria; Pseudomonadati; Thermodesulfobacteriota; Desulfovibrionia;
OC   Desulfovibrionales; Desulfomicrobiaceae; Desulfomicrobium.
OX   NCBI_TaxID=525897 {ECO:0000313|EMBL:ACU88190.1, ECO:0000313|Proteomes:UP000002216};
RN   [1] {ECO:0000313|EMBL:ACU88190.1, ECO:0000313|Proteomes:UP000002216}
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 4028 / VKM B-1378 / X {ECO:0000313|Proteomes:UP000002216};
RX   PubMed=21304634; DOI=10.4056/sigs.13134;
RA   Copeland A., Spring S., Goker M., Schneider S., Lapidus A., Del Rio T.G.,
RA   Tice H., Cheng J.F., Chen F., Nolan M., Bruce D., Goodwin L., Pitluck S.,
RA   Ivanova N., Mavrommatis K., Ovchinnikova G., Pati A., Chen A.,
RA   Palaniappan K., Land M., Hauser L., Chang Y.J., Jeffries C.C., Meincke L.,
RA   Sims D., Brettin T., Detter J.C., Han C., Chain P., Bristow J., Eisen J.A.,
RA   Markowitz V., Hugenholtz P., Kyrpides N.C., Klenk H.P., Lucas S.;
RT   "Complete genome sequence of Desulfomicrobium baculatum type strain (X).";
RL   Stand. Genomic Sci. 1:29-37(2009).
CC   -!- FUNCTION: Catalyzes the conversion of D-ribulose 5-phosphate to formate
CC       and 3,4-dihydroxy-2-butanone 4-phosphate.
CC       {ECO:0000256|ARBA:ARBA00002284, ECO:0000256|HAMAP-Rule:MF_01283}.
CC   -!- FUNCTION: Catalyzes the conversion of GTP to 2,5-diamino-6-
CC       ribosylamino-4(3H)-pyrimidinone 5'-phosphate (DARP), formate and
CC       pyrophosphate. {ECO:0000256|ARBA:ARBA00043932, ECO:0000256|HAMAP-
CC       Rule:MF_01283}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=D-ribulose 5-phosphate = (2S)-2-hydroxy-3-oxobutyl phosphate +
CC         formate + H(+); Xref=Rhea:RHEA:18457, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:15740, ChEBI:CHEBI:58121, ChEBI:CHEBI:58830;
CC         EC=4.1.99.12; Evidence={ECO:0000256|ARBA:ARBA00000141,
CC         ECO:0000256|HAMAP-Rule:MF_01283};
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=GTP + 4 H2O = 2,5-diamino-6-hydroxy-4-(5-phosphoribosylamino)-
CC         pyrimidine + formate + 2 phosphate + 3 H(+); Xref=Rhea:RHEA:23704,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:15740,
CC         ChEBI:CHEBI:37565, ChEBI:CHEBI:43474, ChEBI:CHEBI:58614; EC=3.5.4.25;
CC         Evidence={ECO:0000256|ARBA:ARBA00049295, ECO:0000256|HAMAP-
CC         Rule:MF_01283};
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Evidence={ECO:0000256|HAMAP-
CC         Rule:MF_01283};
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035; Evidence={ECO:0000256|HAMAP-
CC         Rule:MF_01283};
CC       Note=Binds 2 divalent metal cations per subunit. Magnesium or
CC       manganese. {ECO:0000256|HAMAP-Rule:MF_01283};
CC   -!- COFACTOR:
CC       Name=Mn(2+); Xref=ChEBI:CHEBI:29035;
CC         Evidence={ECO:0000256|ARBA:ARBA00001936};
CC   -!- COFACTOR:
CC       Name=Zn(2+); Xref=ChEBI:CHEBI:29105; Evidence={ECO:0000256|HAMAP-
CC         Rule:MF_01283};
CC       Note=Binds 1 zinc ion per subunit. {ECO:0000256|HAMAP-Rule:MF_01283};
CC   -!- PATHWAY: Cofactor biosynthesis; riboflavin biosynthesis; 2-hydroxy-3-
CC       oxobutyl phosphate from D-ribulose 5-phosphate: step 1/1.
CC       {ECO:0000256|ARBA:ARBA00004904, ECO:0000256|HAMAP-Rule:MF_01283}.
CC   -!- PATHWAY: Cofactor biosynthesis; riboflavin biosynthesis; 5-amino-6-(D-
CC       ribitylamino)uracil from GTP: step 1/4. {ECO:0000256|ARBA:ARBA00004853,
CC       ECO:0000256|HAMAP-Rule:MF_01283}.
CC   -!- SIMILARITY: In the C-terminal section; belongs to the GTP
CC       cyclohydrolase II family. {ECO:0000256|ARBA:ARBA00008976,
CC       ECO:0000256|HAMAP-Rule:MF_01283}.
CC   -!- SIMILARITY: In the N-terminal section; belongs to the DHBP synthase
CC       family. {ECO:0000256|ARBA:ARBA00005520, ECO:0000256|HAMAP-
CC       Rule:MF_01283}.
CC   -!- CAUTION: Lacks conserved residue(s) required for the propagation of
CC       feature annotation. {ECO:0000256|HAMAP-Rule:MF_01283}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; CP001629; ACU88190.1; -; Genomic_DNA.
DR   RefSeq; WP_012805275.1; NC_013173.1.
DR   AlphaFoldDB; C7LSH6; -.
DR   STRING; 525897.Dbac_0060; -.
DR   KEGG; dba:Dbac_0060; -.
DR   eggNOG; COG0108; Bacteria.
DR   eggNOG; COG0807; Bacteria.
DR   HOGENOM; CLU_020273_1_2_7; -.
DR   OrthoDB; 9793111at2; -.
DR   UniPathway; UPA00275; UER00399.
DR   Proteomes; UP000002216; Chromosome.
DR   GO; GO:0005829; C:cytosol; IEA:TreeGrafter.
DR   GO; GO:0008686; F:3,4-dihydroxy-2-butanone-4-phosphate synthase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0003935; F:GTP cyclohydrolase II activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0000287; F:magnesium ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0030145; F:manganese ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0008270; F:zinc ion binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0009231; P:riboflavin biosynthetic process; IEA:UniProtKB-UniRule.
DR   CDD; cd00641; GTP_cyclohydro2; 1.
DR   FunFam; 3.40.50.10990:FF:000001; Riboflavin biosynthesis protein RibBA; 1.
DR   FunFam; 3.90.870.10:FF:000001; Riboflavin biosynthesis protein RibBA; 1.
DR   Gene3D; 3.90.870.10; DHBP synthase; 1.
DR   Gene3D; 3.40.50.10990; GTP cyclohydrolase II; 1.
DR   HAMAP; MF_00179; RibA; 1.
DR   HAMAP; MF_00180; RibB; 1.
DR   HAMAP; MF_01283; RibBA; 1.
DR   InterPro; IPR017945; DHBP_synth_RibB-like_a/b_dom.
DR   InterPro; IPR000422; DHBP_synthase_RibB.
DR   InterPro; IPR032677; GTP_cyclohydro_II.
DR   InterPro; IPR000926; RibA.
DR   InterPro; IPR036144; RibA-like_sf.
DR   InterPro; IPR016299; Riboflavin_synth_RibBA.
DR   NCBIfam; NF001591; PRK00393.1; 1.
DR   NCBIfam; NF006803; PRK09311.1; 1.
DR   NCBIfam; TIGR00505; ribA; 1.
DR   NCBIfam; TIGR00506; ribB; 1.
DR   PANTHER; PTHR21327:SF18; 3,4-DIHYDROXY-2-BUTANONE 4-PHOSPHATE SYNTHASE; 1.
DR   PANTHER; PTHR21327; GTP CYCLOHYDROLASE II-RELATED; 1.
DR   Pfam; PF00926; DHBP_synthase; 1.
DR   Pfam; PF00925; GTP_cyclohydro2; 1.
DR   PIRSF; PIRSF001259; RibA; 1.
DR   SUPFAM; SSF142695; RibA-like; 1.
DR   SUPFAM; SSF55821; YrdC/RibB; 1.
PE   3: Inferred from homology;
KW   GTP-binding {ECO:0000256|ARBA:ARBA00023134, ECO:0000256|HAMAP-
KW   Rule:MF_01283};
KW   Hydrolase {ECO:0000256|ARBA:ARBA00022801, ECO:0000256|HAMAP-Rule:MF_01283};
KW   Lyase {ECO:0000256|ARBA:ARBA00023239, ECO:0000256|HAMAP-Rule:MF_01283};
KW   Magnesium {ECO:0000256|ARBA:ARBA00022842, ECO:0000256|HAMAP-Rule:MF_01283};
KW   Manganese {ECO:0000256|ARBA:ARBA00023211, ECO:0000256|HAMAP-Rule:MF_01283};
KW   Metal-binding {ECO:0000256|ARBA:ARBA00022723, ECO:0000256|HAMAP-
KW   Rule:MF_01283};
KW   Multifunctional enzyme {ECO:0000256|ARBA:ARBA00023268, ECO:0000256|HAMAP-
KW   Rule:MF_01283};
KW   Nucleotide-binding {ECO:0000256|ARBA:ARBA00022741, ECO:0000256|HAMAP-
KW   Rule:MF_01283}; Reference proteome {ECO:0000313|Proteomes:UP000002216};
KW   Riboflavin biosynthesis {ECO:0000256|ARBA:ARBA00022619, ECO:0000256|HAMAP-
KW   Rule:MF_01283};
KW   Zinc {ECO:0000256|ARBA:ARBA00022833, ECO:0000256|HAMAP-Rule:MF_01283}.
FT   DOMAIN          208..372
FT                   /note="GTP cyclohydrolase II"
FT                   /evidence="ECO:0000259|Pfam:PF00925"
FT   REGION          1..201
FT                   /note="DHBP synthase"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   REGION          202..404
FT                   /note="GTP cyclohydrolase II"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   ACT_SITE        329
FT                   /note="Proton acceptor; for GTP cyclohydrolase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   ACT_SITE        331
FT                   /note="Nucleophile; for GTP cyclohydrolase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         27..28
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         28
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         28
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         32
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         164
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         252..256
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         257
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         268
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         270
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         273
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         295..297
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         317
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         352
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         357
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   SITE            126
FT                   /note="Essential for DHBP synthase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   SITE            164
FT                   /note="Essential for DHBP synthase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
SQ   SEQUENCE   404 AA;  44379 MW;  D4CB39048F1F5266 CRC64;
     MHKCSAEEAI KEIKAGKMII LVDDEDRENE GDLTIAAEMV TPEAINFMAK YGRGLICLAL
     EPALVDKLEL PLMARRNTSK FGTNFTVSIE AKQGVTTGIS AHDRALTIQT AVADQTTPED
     LATPGHIFPL RAKPGGVLVR AGQTEGSVDL ARLAGLKGAA VICEIMNDDG SMSRMPDLRK
     FAEEHDMKIA TIADLIAYRS RKDSLVRRVA EARMPTCYGE FTIVAYENDI DSHTHIALVK
     GEINEETPVL VRVHSECLTG DVFGSMRCDC GSQLQRAMQM VNDEGAGVIL YMRQEGRGIG
     LGNKIKAYHL QDEGRDTVEA NLELGFAPDL RDYGLGAQIL VDLGVKRMRL LTNNPKKIIG
     LEGYGLKVEE RISIEIPACD DNKCYLHTKH SKLGHLLQFE AENK
//