I4OMT_MEDTR
ID I4OMT_MEDTR Reviewed; 364 AA.
AC Q29U70;
DT 27-JUL-2011, integrated into UniProtKB/Swiss-Prot.
DT 04-APR-2006, sequence version 1.
DT 03-AUG-2022, entry version 75.
DE RecName: Full=Isoflavone 4'-O-methyltransferase;
DE Short=MtHI4'OMT;
DE EC=2.1.1.46 {ECO:0000269|PubMed:17172354};
DE AltName: Full=2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase;
DE EC=2.1.1.212 {ECO:0000269|PubMed:17172354};
GN Name=HI4'OMT;
OS Medicago truncatula (Barrel medic) (Medicago tribuloides).
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC rosids; fabids; Fabales; Fabaceae; Papilionoideae; 50 kb inversion clade;
OC NPAAA clade; Hologalegina; IRL clade; Trifolieae; Medicago.
OX NCBI_TaxID=3880;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY,
RP BIOPHYSICOCHEMICAL PROPERTIES, X-RAY CRYSTALLOGRAPHY (2.35 ANGSTROMS) OF
RP 7-364 IN COMPLEX WITH SUBSTRATES, AND SUBUNIT.
RX PubMed=17172354; DOI=10.1105/tpc.106.041376;
RA Liu C.J., Deavours B.E., Richard S.B., Ferrer J.L., Blount J.W., Huhman D.,
RA Dixon R.A., Noel J.P.;
RT "Structural basis for dual functionality of isoflavonoid O-
RT methyltransferases in the evolution of plant defense responses.";
RL Plant Cell 18:3656-3669(2006).
CC -!- FUNCTION: 2-hydroxyisoflavanone 4'-O-methyltransferase involved in the
CC biosynthesis of the phytoalexin medicarpin. Has also an in vitro (+)-
CC 6a-hydroxymaackiain-3-0-methyltransferase activity, converting the
CC pterocarpan 6a-hydroxymaackiain into pisatin. No activity with di- or
CC trihydroxylated isoflavones, including daidzein and genistein, or with
CC (-)-medicarpin and maackiain. The dual activity for either 3- or 4'-O-
CC methylation depends upon substrate availability.
CC {ECO:0000269|PubMed:17172354}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=a 4'-hydroxyisoflavone + S-adenosyl-L-methionine = a 4'-
CC methoxyisoflavone + H(+) + S-adenosyl-L-homocysteine;
CC Xref=Rhea:RHEA:31739, ChEBI:CHEBI:15378, ChEBI:CHEBI:57856,
CC ChEBI:CHEBI:59789, ChEBI:CHEBI:63328, ChEBI:CHEBI:133959;
CC EC=2.1.1.46; Evidence={ECO:0000269|PubMed:17172354};
CC -!- CATALYTIC ACTIVITY:
CC Reaction=(2R,3S)-2,4',7-trihydroxyisoflavanone + S-adenosyl-L-
CC methionine = (2R,3S)-2,7-dihydroxy-4'-methoxyisoflavanone + H(+) + S-
CC adenosyl-L-homocysteine; Xref=Rhea:RHEA:31371, ChEBI:CHEBI:15378,
CC ChEBI:CHEBI:57856, ChEBI:CHEBI:59789, ChEBI:CHEBI:63325,
CC ChEBI:CHEBI:85906; EC=2.1.1.212;
CC Evidence={ECO:0000269|PubMed:17172354};
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=73.3 uM for 2,7,4'-trihydroxyisoflavanone
CC {ECO:0000269|PubMed:17172354};
CC KM=62.1 uM for 6a-hydroxymaackiain {ECO:0000269|PubMed:17172354};
CC KM=99.8 uM for S-adenosyl-L-methionine {ECO:0000269|PubMed:17172354};
CC Vmax=4.0 nmol/min/mg enzyme with 2,7,4'-trihydroxyisoflavanone as
CC substrate {ECO:0000269|PubMed:17172354};
CC Vmax=17.9 nmol/min/mg enzyme with 6a-hydroxymaackiain as substrate
CC {ECO:0000269|PubMed:17172354};
CC Vmax=23.9 nmol/min/mg enzyme toward S-adenosyl-L-methionine for the
CC 4'-O-methyltransferase activity {ECO:0000269|PubMed:17172354};
CC -!- SUBUNIT: Homodimer. {ECO:0000269|PubMed:17172354}.
CC -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC superfamily. Cation-independent O-methyltransferase family. COMT
CC subfamily. {ECO:0000255|PROSITE-ProRule:PRU01020}.
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DR EMBL; AY942158; AAY18581.1; -; mRNA.
DR RefSeq; XP_013456930.1; XM_013601476.1.
DR PDB; 1ZG3; X-ray; 2.35 A; A=7-364.
DR PDB; 1ZGA; X-ray; 2.35 A; A=8-364.
DR PDB; 1ZGJ; X-ray; 2.50 A; A=11-364.
DR PDB; 1ZHF; X-ray; 2.50 A; A=8-364.
DR PDBsum; 1ZG3; -.
DR PDBsum; 1ZGA; -.
DR PDBsum; 1ZGJ; -.
DR PDBsum; 1ZHF; -.
DR AlphaFoldDB; Q29U70; -.
DR SMR; Q29U70; -.
DR ProMEX; Q29U70; -.
DR EnsemblPlants; KEH30961; KEH30961; MTR_4g088190.
DR GeneID; 25493072; -.
DR Gramene; KEH30961; KEH30961; MTR_4g088190.
DR KEGG; ag:AAY18581; -.
DR HOGENOM; CLU_005533_7_0_1; -.
DR OrthoDB; 817726at2759; -.
DR BRENDA; 2.1.1.212; 3201.
DR BRENDA; 2.1.1.270; 3201.
DR EvolutionaryTrace; Q29U70; -.
DR ExpressionAtlas; Q29U70; differential.
DR GO; GO:0102670; F:2,7,4'-trihydroxyisoflavanone-4'-O-methyltransferase activity; IEA:UniProtKB-EC.
DR GO; GO:0030746; F:isoflavone 4'-O-methyltransferase activity; IEA:UniProtKB-EC.
DR GO; GO:0008171; F:O-methyltransferase activity; IEA:InterPro.
DR GO; GO:0046983; F:protein dimerization activity; IEA:InterPro.
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 3D-structure; Methyltransferase; S-adenosyl-L-methionine; Transferase.
FT CHAIN 1..364
FT /note="Isoflavone 4'-O-methyltransferase"
FT /id="PRO_0000411977"
FT ACT_SITE 268
FT /note="Proton acceptor"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT BINDING 206..209
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT BINDING 230..231
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT BINDING 230
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT BINDING 250..251
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT BINDING 264
FT /ligand="S-adenosyl-L-methionine"
FT /ligand_id="ChEBI:CHEBI:59789"
FT TURN 8..10
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 16..24
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 27..39
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 41..48
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 54..60
FT /evidence="ECO:0007829|PDB:1ZG3"
FT TURN 65..67
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 68..80
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 83..89
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 92..95
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 99..104
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 106..109
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 113..115
FT /evidence="ECO:0007829|PDB:1ZGA"
FT HELIX 120..126
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 129..132
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 133..137
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 138..143
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 150..155
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 159..163
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 166..168
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 169..184
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 186..192
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 194..198
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 201..206
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 212..220
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 224..230
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 232..235
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 242..248
FT /evidence="ECO:0007829|PDB:1ZG3"
FT TURN 251..253
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 259..265
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 267..269
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 272..285
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 286..292
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 294..299
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 309..326
FT /evidence="ECO:0007829|PDB:1ZG3"
FT HELIX 333..342
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 347..353
FT /evidence="ECO:0007829|PDB:1ZG3"
FT TURN 354..356
FT /evidence="ECO:0007829|PDB:1ZG3"
FT STRAND 357..363
FT /evidence="ECO:0007829|PDB:1ZG3"
SQ SEQUENCE 364 AA; 40754 MW; C7C83C858A4BC9E5 CRC64;
MAFSTNGSEE SELYHAQIHL YKHVYNFVSS MALKSAMELG IADAIHNHGK PMTLSELASS
LKLHPSKVNI LHRFLRLLTH NGFFAKTIVK GKEGDEEEEI AYSLTPPSKL LISGKPTCLS
SIVKGALHPS SLDMWSSSKK WFNEDKEQTL FECATGESFW DFLNKDSESS TLSMFQDAMA
SDSRMFKLVL QENKRVFEGL ESLVDVGGGT GGVTKLIHEI FPHLKCTVFD QPQVVGNLTG
NENLNFVGGD MFKSIPSADA VLLKWVLHDW NDEQSLKILK NSKEAISHKG KDGKVIIIDI
SIDETSDDRG LTELQLDYDL VMLTMFLGKE RTKQEWEKLI YDAGFSSYKI TPISGFKSLI
EVYP
