ID   OMT2_CHRAE              Reviewed;         343 AA.
AC   Q42653;
DT   19-OCT-2002, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   20-JAN-2009, entry version 50.
DE   RecName: Full=Quercetin 3-O-methyltransferase 2;
DE            EC=2.1.1.76;
DE   AltName: Full=Flavonol 3-O-methyltransferase 2;
GN   Name=OMT2;
OS   Chrysosplenium americanum (Golden saxifrage).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliophyta; eudicotyledons; core eudicotyledons;
OC   Saxifragales; Saxifragaceae; Chrysosplenium.
OX   NCBI_TaxID=36749;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], AND CHARACTERIZATION.
RC   TISSUE=Leaf;
RX   MEDLINE=98181116; PubMed=9514654; DOI=10.1006/abbi.1997.0554;
RA   Gauthier A., Gulick P.J., Ibrahim R.K.;
RT   "Characterization of two cDNA clones which encode O-methyltransferases
RT   for the methylation of both flavonoid and phenylpropanoid compounds.";
RL   Arch. Biochem. Biophys. 351:243-249(1998).
CC   -!- FUNCTION: Methylates OH residues of flavonoid and phenylpropanoid
CC       compounds and shows a higher affinity for flavonoid than
CC       phenylpropanoid substrates. Substrate preference is quercetin
CC       (flavonoid) = luteolin (flavonoid) = 5-hydroxyferulic acid
CC       (phenylpropanoid) > caffeic acid (phenylpropanoid) >> apigenin
CC       (flavonoid) = kempferol (flavonoid). 3,4-dimethylquercetin is not
CC       a substrate.
CC   -!- CATALYTIC ACTIVITY: S-adenosyl-L-methionine + 3,5,7,3',4'-
CC       pentahydroxyflavone = S-adenosyl-L-homocysteine + 3-methoxy-
CC       5,7,3',4'-tetrahydroxyflavone.
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         Note=The Vmax value for flavonoid compounds methylation is two
CC         to threefold lower for OMT2 than for OMT1;
CC   -!- PATHWAY: Flavonoid metabolism; quercetin degradation.
CC   -!- SUBUNIT: Homodimer (By similarity).
CC   -!- SIMILARITY: Belongs to the methyltransferase superfamily. Type 2
CC       family. COMT subfamily.
CC   -!- CAUTION: It is not sure if OMT1 and OMT2 are really encoded by two
CC       different genes or if they represent cloning artifacts.
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DR   EMBL; U16793; AAA86982.1; -; mRNA.
DR   HSSP; P28002; 1KYZ.
DR   SMR; Q42653; 2-341.
DR   BRENDA; 2.1.1.76; 262661.
DR   GO; GO:0008171; F:O-methyltransferase activity; IEA:InterPro.
DR   GO; GO:0046983; F:protein dimerization activity; IEA:InterPro.
DR   GO; GO:0030755; F:quercetin 3-O-methyltransferase activity; IEA:EC.
DR   InterPro; IPR016461; O-MeTrfase_COMT_euk.
DR   InterPro; IPR001077; O_MeTrfase_2.
DR   InterPro; IPR012967; Plant_MeTrfase_dimerisation.
DR   InterPro; IPR011991; Wing_hlx_DNA_bd.
DR   Gene3D; G3DSA:1.10.10.10; Wing_hlx_DNA_bd; 1.
DR   Pfam; PF08100; Dimerisation; 1.
DR   Pfam; PF00891; Methyltransf_2; 1.
DR   PIRSF; PIRSF005739; O-mtase; 1.
PE   1: Evidence at protein level;
KW   Methyltransferase; S-adenosyl-L-methionine; Transferase.
FT   CHAIN         1    343       Quercetin 3-O-methyltransferase 2.
FT                                /FTId=PRO_0000063216.
FT   ACT_SITE    245    245       Proton acceptor (By similarity).
FT   BINDING     184    184       S-adenosyl-L-methionine; via carbonyl
FT                                oxygen (By similarity).
FT   BINDING     207    207       S-adenosyl-L-methionine (By similarity).
FT   BINDING     227    227       S-adenosyl-L-methionine (By similarity).
FT   BINDING     228    228       S-adenosyl-L-methionine; via amide
FT                                nitrogen (By similarity).
FT   BINDING     241    241       S-adenosyl-L-methionine (By similarity).
SQ   SEQUENCE   343 AA;  37868 MW;  8D363A98330FDE4F CRC64;
     MLFAMQLACA SVLPMVLKSA IELDLLEIIR GQDTCMSPTE IASHLPTTNP DAPAMVDRIL
     RLLSCYSVVT CSVRSVDDQR VYGLAPVCKY LTKNQDGVSI AALCLMNQDK VLMESWYHLK
     DAVLDGGIPF NKAYGMSSFE YHGTDPRFNK VFNRGMSDHS TITMKKVFQT YQGFQGLTSL
     VDVGGGTGAT LTMILSKYPT IRCINFDLPH VIEDAPEYPG IEHVGGDMFV SVPKGDAIFM
     KWICHDWSDE HCLKLLKNCY DALPNNGKVI LAECILPEVP DSSLATKGVV HIDVITVAHN
     PGGKERTEKE FEALAKAAGF QGFQVFCNAF NTYIIEFSKK ICN
//