OMT2_CHRAE
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 03-AUG-2022, entry version 90.
DE RecName: Full=Flavone 3'-O-methyltransferase OMT2 {ECO:0000305};
DE EC=2.1.1.42 {ECO:0000269|PubMed:9514654};
GN Name=OMT2 {ECO:0000303|PubMed:9514654};
OS Chrysosplenium americanum (American golden saxifrage).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC Saxifragales; Saxifragaceae; Chrysosplenium.
OX NCBI_TaxID=36749;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY, AND
RP BIOPHYSICOCHEMICAL PROPERTIES.
RC TISSUE=Leaf;
RX 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 for
RT the methylation of both flavonoid and phenylpropanoid compounds.";
RL Arch. Biochem. Biophys. 351:243-249(1998).
CC -!- FUNCTION: Catalyzes the 3'-O-methylation of the flavonoids luteolin and
CC quercetin (PubMed:9514654). Catalyzes the 3- of 5-O-methylation of the
CC phenylpropanoids caffeate and 5-hydroxyferulate (PubMed:9514654).
CC Substrate preference is 5-hydroxyferulate > luteolin > quercetin >
CC caffeate (PubMed:9514654). Apigenin, kempferol and 3,4-
CC dimethylquercetin do not seem to be substrates for methylation
CC (PubMed:9514654). {ECO:0000269|PubMed:9514654}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(E)-5-hydroxyferulate + S-adenosyl-L-methionine = E-sinapate +
CC H(+) + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:60952,
CC ChEBI:CHEBI:15378, ChEBI:CHEBI:30023, ChEBI:CHEBI:57856,
CC ChEBI:CHEBI:59789, ChEBI:CHEBI:144381;
CC Evidence={ECO:0000269|PubMed:9514654};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:60953;
CC Evidence={ECO:0000269|PubMed:9514654};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=luteolin + S-adenosyl-L-methionine = chrysoeriol + H(+) + S-
CC adenosyl-L-homocysteine; Xref=Rhea:RHEA:14589, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:57545, ChEBI:CHEBI:57799, ChEBI:CHEBI:57856,
CC ChEBI:CHEBI:59789; Evidence={ECO:0000269|PubMed:9514654};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:14590;
CC Evidence={ECO:0000269|PubMed:9514654};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=quercetin + S-adenosyl-L-methionine = H(+) + isorhamnetin + S-
CC adenosyl-L-homocysteine; Xref=Rhea:RHEA:60944, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:57694, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789,
CC ChEBI:CHEBI:144055; Evidence={ECO:0000269|PubMed:9514654};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:60945;
CC Evidence={ECO:0000269|PubMed:9514654};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(E)-caffeate + S-adenosyl-L-methionine = (E)-ferulate + H(+) +
CC S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:20225, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:29749, ChEBI:CHEBI:57770, ChEBI:CHEBI:57856,
CC ChEBI:CHEBI:59789; Evidence={ECO:0000269|PubMed:9514654};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:20226;
CC Evidence={ECO:0000269|PubMed:9514654};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 3'-hydroxyflavone + S-adenosyl-L-methionine = a 3'-
CC methoxyflavone + H(+) + S-adenosyl-L-homocysteine;
CC Xref=Rhea:RHEA:55332, ChEBI:CHEBI:15378, ChEBI:CHEBI:27741,
CC ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:138730;
CC EC=2.1.1.42; Evidence={ECO:0000269|PubMed:9514654};
CC PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:55333;
CC Evidence={ECO:0000269|PubMed:9514654};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=2.77 uM for quercetin {ECO:0000269|PubMed:9514654};
CC KM=3.3 uM for luteolin {ECO:0000269|PubMed:9514654};
CC KM=16.22 uM for 5-hydroxyferrulate {ECO:0000269|PubMed:9514654};
CC KM=19.6 uM for caffeate {ECO:0000269|PubMed:9514654};
CC Vmax=18.2 nmol/sec/mg enzyme with quercetin as substrate
CC {ECO:0000269|PubMed:9514654};
CC Vmax=18.5 nmol/sec/mg enzyme with luteolin as substrate
CC {ECO:0000269|PubMed:9514654};
CC Vmax=82 nmol/sec/mg enzyme with 5-hydroxyferrulate as substrate
CC {ECO:0000269|PubMed:9514654};
CC Vmax=24.6 nmol/sec/mg enzyme with caffeate as substrate
CC {ECO:0000269|PubMed:9514654};
CC -!- PATHWAY: Flavonoid metabolism. {ECO:0000305}.
CC -!- SUBUNIT: Homodimer. {ECO:0000250|UniProtKB:P28002}.
CC -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC superfamily. Cation-independent O-methyltransferase family. COMT
CC subfamily. {ECO:0000305}.
CC -!- CAUTION: It is not sure whether OMT1 and OMT2 are really encoded by two
CC different genes or if they represent cloning artifacts. {ECO:0000305}.
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DR EMBL; U16793; AAA86982.1; -; mRNA.
DR AlphaFoldDB; Q42653; -.
DR SMR; Q42653; -.
DR KEGG; ag:AAA86982; -.
DR BioCyc; MetaCyc:MON-17791; -.
DR GO; GO:0047763; F:caffeate O-methyltransferase activity; IEA:RHEA.
DR GO; GO:0030744; F:luteolin O-methyltransferase activity; IDA:UniProtKB.
DR GO; GO:0046983; F:protein dimerization activity; IEA:InterPro.
DR GO; GO:0102822; F:quercetin 3'-O-methyltransferase activity; IEA:UniProtKB-EC.
DR GO; GO:0030755; F:quercetin 3-O-methyltransferase activity; IDA:UniProtKB.
DR GO; GO:0009812; P:flavonoid metabolic process; IDA:UniProtKB.
DR GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR Gene3D; 1.10.10.10; -; 1.
DR Gene3D; 3.40.50.150; -; 1.
DR InterPro; IPR016461; COMT-like.
DR InterPro; IPR001077; O_MeTrfase_dom.
DR InterPro; IPR012967; Plant_MeTrfase_dimerisation.
DR InterPro; IPR029063; SAM-dependent_MTases_sf.
DR InterPro; IPR036388; WH-like_DNA-bd_sf.
DR InterPro; IPR036390; WH_DNA-bd_sf.
DR PANTHER; PTHR11746; PTHR11746; 1.
DR Pfam; PF08100; Dimerisation; 1.
DR Pfam; PF00891; Methyltransf_2; 1.
DR PIRSF; PIRSF005739; O-mtase; 1.
DR SUPFAM; SSF46785; SSF46785; 1.
DR SUPFAM; SSF53335; SSF53335; 1.
DR PROSITE; PS51683; SAM_OMT_II; 1.
PE 1: Evidence at protein level;
KW Methyltransferase; S-adenosyl-L-methionine; Transferase.
FT CHAIN 1..343
FT /note="Flavone 3'-O-methyltransferase OMT2"
FT /id="PRO_0000063216"
FT ACT_SITE 245
FT /note="Proton acceptor"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT ACT_SITE 273
FT /evidence="ECO:0000250|UniProtKB:F1DBB3"
FT ACT_SITE 305
FT /evidence="ECO:0000250|UniProtKB:F1DBB3"
FT BINDING 184
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000250|UniProtKB:P28002"
FT BINDING 207
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT BINDING 227
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000250|UniProtKB:P28002"
FT BINDING 228
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000250|UniProtKB:P28002"
FT BINDING 241
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000250|UniProtKB:P28002"
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
