ID   B7K0C3_RIPO1            Unreviewed;       556 AA.
AC   B7K0C3;
DT   10-FEB-2009, integrated into UniProtKB/TrEMBL.
DT   10-FEB-2009, sequence version 1.
DT   27-MAR-2024, entry version 107.
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=PCC8801_3439 {ECO:0000313|EMBL:ACK67407.1};
OS   Rippkaea orientalis (strain PCC 8801 / RF-1) (Cyanothece sp. (strain PCC
OS   8801)).
OC   Bacteria; Cyanobacteriota; Cyanophyceae; Oscillatoriophycideae;
OC   Chroococcales; Aphanothecaceae; Rippkaea; Rippkaea orientalis.
OX   NCBI_TaxID=41431 {ECO:0000313|EMBL:ACK67407.1, ECO:0000313|Proteomes:UP000008204};
RN   [1] {ECO:0000313|Proteomes:UP000008204}
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=PCC 8801 {ECO:0000313|Proteomes:UP000008204};
RX   PubMed=21972240; DOI=10.1128/mBio.00214-11;
RA   Bandyopadhyay A., Elvitigala T., Welsh E., Stockel J., Liberton M., Min H.,
RA   Sherman L.A., Pakrasi H.B.;
RT   "Novel metabolic attributes of the genus Cyanothece, comprising a group of
RT   unicellular nitrogen-fixing Cyanobacteria.";
RL   MBio 2:E214-E214(2011).
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|HAMAP-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 + 3 H(+) + 2 phosphate; 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:ARBA00029293, 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|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}.
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DR   EMBL; CP001287; ACK67407.1; -; Genomic_DNA.
DR   RefSeq; WP_012596667.1; NC_011726.1.
DR   AlphaFoldDB; B7K0C3; -.
DR   STRING; 41431.PCC8801_3439; -.
DR   KEGG; cyp:PCC8801_3439; -.
DR   eggNOG; COG0108; Bacteria.
DR   eggNOG; COG0807; Bacteria.
DR   HOGENOM; CLU_020273_0_1_3; -.
DR   OrthoDB; 9793111at2; -.
DR   UniPathway; UPA00275; UER00399.
DR   Proteomes; UP000008204; Chromosome.
DR   GO; GO:0008686; F:3,4-dihydroxy-2-butanone-4-phosphate synthase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0005525; F:GTP binding; IEA:UniProtKB-KW.
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   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; TIGR00505; ribA; 1.
DR   NCBIfam; TIGR00506; ribB; 1.
DR   PANTHER; PTHR21327; GTP CYCLOHYDROLASE II-RELATED; 1.
DR   PANTHER; PTHR21327:SF48; RIBOFLAVIN BIOSYNTHESIS PROTEIN RIBBA; 1.
DR   Pfam; PF00926; DHBP_synthase; 1.
DR   Pfam; PF00925; GTP_cyclohydro2; 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:UP000008204};
KW   Riboflavin biosynthesis {ECO:0000256|ARBA:ARBA00022619, ECO:0000256|HAMAP-
KW   Rule:MF_01283}; Zinc {ECO:0000256|HAMAP-Rule:MF_01283}.
FT   DOMAIN          221..385
FT                   /note="GTP cyclohydrolase II"
FT                   /evidence="ECO:0000259|Pfam:PF00925"
FT   REGION          1..211
FT                   /note="DHBP synthase"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   REGION          212..556
FT                   /note="GTP cyclohydrolase II"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   ACT_SITE        341
FT                   /note="Proton acceptor; for GTP cyclohydrolase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   ACT_SITE        343
FT                   /note="Nucleophile; for GTP cyclohydrolase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         35..36
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         36
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="1"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         36
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         40
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         150..154
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         153
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /ligand_label="2"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         174
FT                   /ligand="D-ribulose 5-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:58121"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         264..268
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         269
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         280
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         282
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /ligand_note="catalytic"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         285
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         307..309
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         329
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         364
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   BINDING         369
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   SITE            136
FT                   /note="Essential for DHBP synthase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
FT   SITE            174
FT                   /note="Essential for DHBP synthase activity"
FT                   /evidence="ECO:0000256|HAMAP-Rule:MF_01283"
SQ   SEQUENCE   556 AA;  61992 MW;  ABDD8DBF8EF3DE98 CRC64;
     MDASPNAIAQ FDTIDAALAD IKAGKAIIVV DDENRENEGD LICAAQFATP NMINFMAVEA
     RGLICLAMMG ERLDTLDLPL MVTKNTDSNQ TAFTVSIDAA KHLGVSTGIS AEDRARTIQV
     AINPDTHPDD LTRPGHIFPI RAKEGGVLKR AGHTEAAVDL SRLAGLYPAG VICEIQNPDG
     SMARLPELFE YAKKHELKLI SIADLISYRL KHDRFVYRET VCQFPSQFGT FQLYAYRNVL
     DGTEHVAIVK GDPAQFKDQP VMVRMHSECL TGDALGSMRC DCRMQLQTAL KMIEGSGLGV
     VVYLRQEGRG IGLVNKLKAY SLQDMGLDTV EANERLGFPA DLRDYGMGAQ MLNDLGVKQI
     RLITNNPRKI AGLKGYGLEV VDRVPLLIEA NDYNANYLAT KAEKLGHLLL HTYLITVAID
     WETEMRSAKE RYGNLEKLRQ LCRSSQLLLQ EEVRPIANAL FSSPSLIFHL GFEQGKMVDP
     HWYHNSKHPY LSAIAQILDE IVTWPNIKRL EFLISSGDDP LLGLQVQLDR HTFSLKDQPS
     EYLRELEMQT IYSFQG
//