ID   CUCS_SIRGR              Reviewed;         759 AA.
AC   K7NBZ9;
DT   02-DEC-2020, integrated into UniProtKB/Swiss-Prot.
DT   06-FEB-2013, sequence version 1.
DT   25-MAY-2022, entry version 40.
DE   RecName: Full=Cucurbitadienol synthase {ECO:0000303|PubMed:25759326};
DE            Short=SgCbQ {ECO:0000303|PubMed:25759326};
DE            EC=5.4.99.33 {ECO:0000269|PubMed:25759326, ECO:0000269|PubMed:29192442};
GN   Name=CBQ {ECO:0000303|PubMed:25759326};
GN   Synonyms=CBS {ECO:0000303|PubMed:29192442};
OS   Siraitia grosvenorii (Monk's fruit) (Luo han guo).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Cucurbitales; Cucurbitaceae; Siraitieae; Siraitia.
OX   NCBI_TaxID=190515;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RA   Tang Q., Ma X.J., Zhao H., Mo C.M.;
RT   "Cloning of genes related to mogrosides biosynthesis in Siraitia
RT   grosvenorii.";
RL   Submitted (AUG-2010) to the EMBL/GenBank/DDBJ databases.
RN   [2]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, AND CATALYTIC ACTIVITY.
RX   PubMed=29192442; DOI=10.19540/j.cnki.cjcmm.20170714.003;
RA   Li S.L., Wang D., Liu Y., Lin T.T., Tang J.L., Hua E.B., Zhang X.L.,
RA   Dai Z.B., Huang L.Q.;
RT   "Study of heterologous efficient synthesis of cucurbitadienol.";
RL   Zhongguo Zhong Yao Za Zhi 42:3326-3331(2017).
RN   [3]
RP   FUNCTION, AND CATALYTIC ACTIVITY.
RX   PubMed=25759326; DOI=10.1093/pcp/pcv043;
RA   Dai L., Liu C., Zhu Y., Zhang J., Men Y., Zeng Y., Sun Y.;
RT   "Functional characterization of cucurbitadienol synthase and triterpene
RT   glycosyltransferase involved in biosynthesis of mogrosides from Siraitia
RT   grosvenorii.";
RL   Plant Cell Physiol. 56:1172-1182(2015).
CC   -!- FUNCTION: Oxidosqualene cyclase involved in the biosynthesis of the
CC       highly oxygenated tetracyclic triterpenes mogrosides and cucurbitacins
CC       (PubMed:29192442, PubMed:25759326). Converts oxidosqualene to
CC       cucurbitadienol (PubMed:29192442, PubMed:25759326).
CC       {ECO:0000269|PubMed:25759326, ECO:0000269|PubMed:29192442}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=(S)-2,3-epoxysqualene = cucurbitadienol; Xref=Rhea:RHEA:30999,
CC         ChEBI:CHEBI:15441, ChEBI:CHEBI:62456; EC=5.4.99.33;
CC         Evidence={ECO:0000269|PubMed:25759326, ECO:0000269|PubMed:29192442};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:31000;
CC         Evidence={ECO:0000269|PubMed:25759326, ECO:0000269|PubMed:29192442};
CC   -!- MISCELLANEOUS: Cucurbitadienol has anti-inflammation, anti-cancer
CC       activities, and acts as a precursor of traditional Chinese medicine
CC       active ingredients mogroside and cucurbitacin.
CC       {ECO:0000305|PubMed:29192442}.
CC   -!- SIMILARITY: Belongs to the terpene cyclase/mutase family.
CC       {ECO:0000305}.
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DR   EMBL; HQ128567; AEM42982.1; -; mRNA.
DR   EMBL; MF596154; AUC64917.1; -; mRNA.
DR   AlphaFoldDB; K7NBZ9; -.
DR   SMR; K7NBZ9; -.
DR   BRENDA; 5.4.99.33; 3400.
DR   GO; GO:0005811; C:lipid droplet; IEA:InterPro.
DR   GO; GO:0034076; F:cucurbitadienol synthase activity; IDA:UniProtKB.
DR   GO; GO:0016104; P:triterpenoid biosynthetic process; IEA:InterPro.
DR   CDD; cd02892; SQCY_1; 1.
DR   InterPro; IPR032696; SQ_cyclase_C.
DR   InterPro; IPR032697; SQ_cyclase_N.
DR   InterPro; IPR018333; Squalene_cyclase.
DR   InterPro; IPR002365; Terpene_synthase_CS.
DR   InterPro; IPR008930; Terpenoid_cyclase/PrenylTrfase.
DR   PANTHER; PTHR11764; PTHR11764; 1.
DR   Pfam; PF13243; SQHop_cyclase_C; 1.
DR   Pfam; PF13249; SQHop_cyclase_N; 1.
DR   SFLD; SFLDG01016; Prenyltransferase_Like_2; 1.
DR   SUPFAM; SSF48239; SSF48239; 2.
DR   TIGRFAMs; TIGR01787; squalene_cyclas; 1.
DR   PROSITE; PS01074; TERPENE_SYNTHASES; 1.
PE   1: Evidence at protein level;
KW   Isomerase; Repeat.
FT   CHAIN           1..759
FT                   /note="Cucurbitadienol synthase"
FT                   /id="PRO_0000451486"
SQ   SEQUENCE   759 AA;  86449 MW;  8172B4511A508A71 CRC64;
     MWRLKVGAES VGENDEKWLK SISNHLGRQV WEFCPDAGTQ QQLLQVHKAR KAFHDDRFHR
     KQSSDLFITI QYGKEVENGG KTAGVKLKEG EEVRKEAVES SLERALSFYS SIQTSDGNWA
     SDLGGPMFLL PGLVIALYVT GVLNSVLSKH HRQEMCRYVY NHQNEDGGWG LHIEGPSTMF
     GSALNYVALR LLGEDANAGA MPKARAWILD HGGATGITSW GKLWLSVLGV YEWSGNNPLP
     PEFWLFPYFL PFHPGRMWCH CRMVYLPMSY LYGKRFVGPI TPIVLSLRKE LYAVPYHEID
     WNKSRNTCAK EDLYYPHPKM QDILWGSLHH VYEPLFTRWP AKRLREKALQ TAMQHIHYED
     ENTRYICLGP VNKVLNLLCC WVEDPYSDAF KLHLQRVHDY LWVAEDGMKM QGYNGSQLWD
     TAFSIQAIVS TKLVDNYGPT LRKAHDFVKS SQIQQDCPGD PNVWYRHIHK GAWPFSTRDH
     GWLISDCTAE GLKAALMLSK LPSETVGESL ERNRLCDAVN VLLSLQNDNG GFASYELTRS
     YPWLELINPA ETFGDIVIDY PYVECTSATM EALTLFKKLH PGHRTKEIDT AIVRAANFLE
     NMQRTDGSWY GCWGVCFTYA GWFGIKGLVA AGRTYNNCLA IRKACDFLLS KELPGGGWGE
     SYLSCQNKVY TNLEGNRPHL VNTAWVLMAL IEAGQAERDP TPLHRAARLL INSQLENGDF
     PQQEIMGVFN KNCMITYAAY RNIFPIWALG EYCHRVLTE