ID   GCH3_SULIA              Reviewed;         230 AA.
AC   C3MZ63;
DT   22-SEP-2009, integrated into UniProtKB/Swiss-Prot.
DT   16-JUN-2009, sequence version 1.
DT   25-MAY-2022, entry version 46.
DE   RecName: Full=GTP cyclohydrolase III {ECO:0000255|HAMAP-Rule:MF_00608};
DE            EC=3.5.4.29 {ECO:0000255|HAMAP-Rule:MF_00608};
GN   Name=gch3 {ECO:0000255|HAMAP-Rule:MF_00608}; OrderedLocusNames=M1627_1820;
OS   Sulfolobus islandicus (strain M.16.27).
OC   Archaea; Crenarchaeota; Thermoprotei; Sulfolobales; Sulfolobaceae;
OC   Sulfolobus.
OX   NCBI_TaxID=427318;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=M.16.27;
RX   PubMed=19435847; DOI=10.1073/pnas.0808945106;
RA   Reno M.L., Held N.L., Fields C.J., Burke P.V., Whitaker R.J.;
RT   "Biogeography of the Sulfolobus islandicus pan-genome.";
RL   Proc. Natl. Acad. Sci. U.S.A. 106:8605-8610(2009).
CC   -!- FUNCTION: Catalyzes the formation of 2-amino-5-formylamino-6-
CC       ribofuranosylamino-4(3H)-pyrimidinone ribonucleotide monophosphate and
CC       inorganic phosphate from GTP. Also has an independent pyrophosphate
CC       phosphohydrolase activity. {ECO:0000255|HAMAP-Rule:MF_00608}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=GTP + 3 H2O = 2-amino-5-formylamino-6-(5-phospho-D-
CC         ribosylamino)pyrimidin-4(3H)-one + 2 H(+) + 2 phosphate;
CC         Xref=Rhea:RHEA:22468, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:37565, ChEBI:CHEBI:43474, ChEBI:CHEBI:57258; EC=3.5.4.29;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00608};
CC   -!- SIMILARITY: Belongs to the archaeal-type GTP cyclohydrolase family.
CC       {ECO:0000255|HAMAP-Rule:MF_00608}.
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DR   EMBL; CP001401; ACP55695.1; -; Genomic_DNA.
DR   RefSeq; WP_012718947.1; NC_012632.1.
DR   AlphaFoldDB; C3MZ63; -.
DR   SMR; C3MZ63; -.
DR   EnsemblBacteria; ACP55695; ACP55695; M1627_1820.
DR   GeneID; 7812484; -.
DR   KEGG; sim:M1627_1820; -.
DR   HOGENOM; CLU_080076_0_0_2; -.
DR   OMA; VQIAHID; -.
DR   Proteomes; UP000002307; Chromosome.
DR   GO; GO:0005525; F:GTP binding; IEA:UniProtKB-KW.
DR   GO; GO:0043740; F:GTP cyclohydrolase IIa activity; IEA:UniProtKB-EC.
DR   GO; GO:0009058; P:biosynthetic process; IEA:InterPro.
DR   Gene3D; 3.30.70.1230; -; 1.
DR   Gene3D; 3.30.70.270; -; 1.
DR   HAMAP; MF_00608; GTP_cyclohydro_3; 1.
DR   InterPro; IPR007839; GTP_CycHdrlase_3.
DR   InterPro; IPR029787; Nucleotide_cyclase.
DR   InterPro; IPR043128; Rev_trsase/Diguanyl_cyclase.
DR   PANTHER; PTHR42202; PTHR42202; 1.
DR   Pfam; PF05165; GCH_III; 1.
DR   PIRSF; PIRSF009265; GTP_cyclohydro_3; 1.
PE   3: Inferred from homology;
KW   GTP-binding; Hydrolase; Nucleotide-binding.
FT   CHAIN           1..230
FT                   /note="GTP cyclohydrolase III"
FT                   /id="PRO_1000212259"
SQ   SEQUENCE   230 AA;  26734 MW;  3591A551AB06F500 CRC64;
     MKVLAIKLVD YREWTERLGY DREWLIQKIQ NKFMMKIHEI ASQYSTFPLQ LRFDNLLMIV
     DGITNTQLIY MINDMQENLP VGIKTCLGYG KTPLEAQWNA SVCLNNKEDK FKEYVDEKIA
     ALHFDINFNT EALKYTSVYD SFLEITNIYV DLSRFLYKIG GILQYLGGDN YLGFVSTNSV
     NKVIEKFSDD NKIKVGIGIG QNARTAIKLA TTSLEKIRNN REKTWHIEEE