ID   SQMT2_BOTBR             Reviewed;         378 AA.
AC   H2E7T6;
DT   06-MAR-2013, integrated into UniProtKB/Swiss-Prot.
DT   21-MAR-2012, sequence version 1.
DT   03-AUG-2022, entry version 31.
DE   RecName: Full=Squalene methyltransferase 2;
DE            EC=2.1.1.262;
DE   AltName: Full=Triterpene methyltransferase 2;
GN   Name=TMT-2;
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.
RX   PubMed=22241476; DOI=10.1074/jbc.m111.316059;
RA   Niehaus T.D., Kinison S., Okada S., Yeo Y.S., Bell S.A., Cui P.,
RA   Devarenne T.P., Chappell J.;
RT   "Functional identification of triterpene methyltransferases from
RT   Botryococcus braunii race B.";
RL   J. Biol. Chem. 287:8163-8173(2012).
CC   -!- FUNCTION: Converts squalene to mono- and dimethyl derivatives, but not
CC       to tri- and tetramethylated products. Unable to methylate cycloartenol,
CC       zymosterol or lanosterol. Methylates both C-3 and C22 positions, but
CC       only C-3 position in monomethylated products. Produces mainly
CC       monomethylated squalene and only 20% of dimethylated squalene.
CC       {ECO:0000269|PubMed:22241476}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=2 S-adenosyl-L-methionine + squalene = 3,22-dimethyl-
CC         1,2,23,24-tetradehydro-2,3,22,23-tetrahydrosqualene + 2 H(+) + 2 S-
CC         adenosyl-L-homocysteine; Xref=Rhea:RHEA:34643, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:15440, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789,
CC         ChEBI:CHEBI:70861; EC=2.1.1.262;
CC         Evidence={ECO:0000269|PubMed:22241476};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=22.5 uM for squalene {ECO:0000269|PubMed:22241476};
CC   -!- SUBCELLULAR LOCATION: Microsome membrane {ECO:0000305}; Single-pass
CC       membrane protein {ECO:0000305}.
CC   -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC       superfamily. Erg6/SMT family. {ECO:0000255|PROSITE-ProRule:PRU01022}.
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DR   EMBL; JN828963; AEY68257.1; -; mRNA.
DR   AlphaFoldDB; H2E7T6; -.
DR   SMR; H2E7T6; -.
DR   KEGG; ag:AEY68257; -.
DR   BioCyc; MetaCyc:MON-17323; -.
DR   SABIO-RK; H2E7T6; -.
DR   GO; GO:0005783; C:endoplasmic reticulum; IEA:UniProtKB-KW.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0008168; F:methyltransferase activity; IEA:UniProtKB-KW.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   GO; GO:0006694; P:steroid biosynthetic process; IEA:InterPro.
DR   Gene3D; 3.40.50.150; -; 1.
DR   InterPro; IPR013216; Methyltransf_11.
DR   InterPro; IPR030384; MeTrfase_SMT.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   InterPro; IPR044625; SMT2/3-like.
DR   InterPro; IPR013705; Sterol_MeTrfase_C.
DR   PANTHER; PTHR44742; PTHR44742; 1.
DR   Pfam; PF08241; Methyltransf_11; 1.
DR   Pfam; PF08498; Sterol_MT_C; 1.
DR   SUPFAM; SSF53335; SSF53335; 1.
DR   PROSITE; PS51685; SAM_MT_ERG6_SMT; 1.
PE   1: Evidence at protein level;
KW   Endoplasmic reticulum; Lipid biosynthesis; Lipid metabolism; Membrane;
KW   Methyltransferase; Microsome; S-adenosyl-L-methionine; Transferase;
KW   Transmembrane; Transmembrane helix.
FT   CHAIN           1..378
FT                   /note="Squalene methyltransferase 2"
FT                   /id="PRO_0000421356"
FT   TRANSMEM        17..37
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   378 AA;  41581 MW;  B8F77029042EA1E8 CRC64;
     MAVDLLSIYG PGLFESLLTV KGATGLIAAL ILGYIIITRL PGQKTKPKLL DLTAGGIPFE
     KVGEVFNDYD KSYGKGTHGE LHVQDTNKVF QLANTFYDFV TDGYEWAWGS SFHFSQRMPG
     LSHAASQMLH ESRMASYLRL KPGMTCLDVG CGVGNPGRTV AACSGAVVTG ITINKYQIQR
     AEYHNRRTGL VGFFKPTVGN FCNMPFDAKS FDAAFAMDAT CHAPKLEDVY GEVFRVLKPG
     GFFATYEWVS TKNYDPTNTR HVKVMNSIIF GNGLPNIRSW KQAEEAGENV GFKLLTSFDL
     ATAPPVGKPW YYVPELMVKY GLLKIQKALV RGACSLGLLP DQSWKVCNMV ADMVPNLVEG
     GATDIFTPMH LLIFQKPE