ID   PSDS_BOTBR              Reviewed;         403 AA.
AC   G0Y286;
DT   06-MAR-2013, integrated into UniProtKB/Swiss-Prot.
DT   19-OCT-2011, sequence version 1.
DT   03-AUG-2022, entry version 32.
DE   RecName: Full=Presqualene diphosphate synthase {ECO:0000305};
DE            EC=2.5.1.103 {ECO:0000269|PubMed:21746901};
DE   AltName: Full=Squalene synthase-like 1;
GN   Name=SSL-1;
OS   Botryococcus braunii (Green alga).
OC   Eukaryota; Viridiplantae; Chlorophyta; core chlorophytes; Trebouxiophyceae;
OC   Trebouxiophyceae incertae sedis; Elliptochloris clade; Botryococcus.
OX   NCBI_TaxID=38881;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY, AND
RP   BIOPHYSICOCHEMICAL PROPERTIES.
RC   STRAIN=Race B;
RX   PubMed=21746901; DOI=10.1073/pnas.1106222108;
RA   Niehaus T.D., Okada S., Devarenne T.P., Watt D.S., Sviripa V., Chappell J.;
RT   "Identification of unique mechanisms for triterpene biosynthesis in
RT   Botryococcus braunii.";
RL   Proc. Natl. Acad. Sci. U.S.A. 108:12260-12265(2011).
CC   -!- FUNCTION: Catalyzes the biosynthesis of presqualene diphosphate (PSPP).
CC       Works in combination with SSL-2 or SSL-3 to produce respectively
CC       squalene or botryococcene. In most other species, farnesyl diphosphate
CC       (FPP) is converted into squalene in a two-step reaction by a single
CC       enzyme. {ECO:0000269|PubMed:21746901}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 (2E,6E)-farnesyl diphosphate = diphosphate + presqualene
CC         diphosphate; Xref=Rhea:RHEA:22672, ChEBI:CHEBI:33019,
CC         ChEBI:CHEBI:57310, ChEBI:CHEBI:175763; EC=2.5.1.103;
CC         Evidence={ECO:0000269|PubMed:21746901};
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC         Evidence={ECO:0000250|UniProtKB:P37268};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=12.8 uM for (2E,6E)-farnesyl diphosphate
CC         {ECO:0000269|PubMed:21746901};
CC         Note=kcat is 0.27 sec(-1) with farnesyl diphosphate as substrate. Not
CC         stimulated by NADPH addition.;
CC   -!- SIMILARITY: Belongs to the phytoene/squalene synthase family.
CC       {ECO:0000305}.
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DR   EMBL; HQ585058; AEL16715.1; -; mRNA.
DR   AlphaFoldDB; G0Y286; -.
DR   SMR; G0Y286; -.
DR   KEGG; ag:AEL16715; -.
DR   BioCyc; MetaCyc:MON-17313; -.
DR   BRENDA; 2.5.1.103; 915.
DR   GO; GO:0004310; F:farnesyl-diphosphate farnesyltransferase activity; IEA:InterPro.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0008610; P:lipid biosynthetic process; IEA:InterPro.
DR   CDD; cd00683; Trans_IPPS_HH; 1.
DR   Gene3D; 1.10.600.10; -; 1.
DR   InterPro; IPR008949; Isoprenoid_synthase_dom_sf.
DR   InterPro; IPR002060; Squ/phyt_synthse.
DR   InterPro; IPR006449; Squal_synth-like.
DR   InterPro; IPR044844; Trans_IPPS_euk-type.
DR   InterPro; IPR033904; Trans_IPPS_HH.
DR   PANTHER; PTHR11626; PTHR11626; 1.
DR   Pfam; PF00494; SQS_PSY; 1.
DR   SFLD; SFLDG01018; Squalene/Phytoene_Synthase_Lik; 1.
DR   SUPFAM; SSF48576; SSF48576; 1.
DR   TIGRFAMs; TIGR01559; squal_synth; 1.
PE   1: Evidence at protein level;
KW   Magnesium; Metal-binding; Transferase.
FT   CHAIN           1..403
FT                   /note="Presqualene diphosphate synthase"
FT                   /id="PRO_0000421361"
FT   BINDING         84
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250|UniProtKB:P37268"
FT   BINDING         87
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250|UniProtKB:P37268"
FT   BINDING         88
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT                   /evidence="ECO:0000250|UniProtKB:P37268"
SQ   SEQUENCE   403 AA;  45953 MW;  53F2BEA6C1DA39B8 CRC64;
     MTMHQDHGVM KDLVKHPNEF PYLLQLAATT YGSPAAPIPK EPDRAFCYNT LHTVSKGFPR
     FVMRLPQELQ DPICIFYLLL RALDTVEDDM NLKSETKISL LRVFHEHCSD RNWSMKSDYG
     IYADLMERFP LVVSVLEKLP PATQQTFREN VKYMGNGMAD FIDKQILTVD EYDLYCHYVA
     GSCGIAVTKV IVQFNLATPE ADSYDFSNSL GLLLQKANII TDYNEDINEE PRPRMFWPQE
     IWGKYAEKLA DFNEPENIDT AVKCLNHMVT DAMRHIEPSL KGMVYFTDKT VFRALALLLV
     TAFGHLSTLY NNPNVFKEKV RQRKGRIARL VMSSRNVPGL FRTCLKLANN FESRCKQETA
     NDPTVAMTIK RLQSIQATCR DGLAKYDTPS GLKSFCAAPT PTK