ID   COMT1_POPKI             Reviewed;         365 AA.
AC   Q43046;
DT   11-APR-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 86.
DE   RecName: Full=Caffeic acid 3-O-methyltransferase 1;
DE            Short=CAOMT-1;
DE            Short=COMT-1;
DE            EC=2.1.1.68;
DE   AltName: Full=S-adenosysl-L-methionine:caffeic acid 3-O-methyltransferase 1;
GN   Name=HOMT1;
OS   Populus kitakamiensis (Aspen) (Populus sieboldii x Populus grandidentata).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; fabids; Malpighiales; Salicaceae; Saliceae; Populus.
OX   NCBI_TaxID=34292;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA   Hayakawa T., Nanto K., Kawai S., Katayama Y., Morohoshi N.;
RT   "Molecular cloning and tissue-specific expression of two genes that encode
RT   caffeic acid O-methyltransferases from Populus kitakamiensis.";
RL   Plant Sci. 113:157-165(1996).
CC   -!- FUNCTION: Catalyzes the conversion of caffeic acid to ferulic acid and
CC       of 5-hydroxyferulic acid to sinapic acid. The resulting products may
CC       subsequently be converted to the corresponding alcohols that are
CC       incorporated into lignins.
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; EC=2.1.1.68;
CC   -!- PATHWAY: Aromatic compound metabolism; phenylpropanoid biosynthesis.
CC   -!- SUBUNIT: Homodimer. {ECO:0000250}.
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; D49710; BAA08558.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q43046; -.
DR   SMR; Q43046; -.
DR   UniPathway; UPA00711; -.
DR   GO; GO:0047763; F:caffeate O-methyltransferase activity; IEA:UniProtKB-EC.
DR   GO; GO:0046983; F:protein dimerization activity; IEA:InterPro.
DR   GO; GO:0009809; P:lignin biosynthetic process; IEA:UniProtKB-KW.
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   3: Inferred from homology;
KW   Lignin biosynthesis; Methyltransferase; S-adenosyl-L-methionine;
KW   Transferase.
FT   CHAIN           1..365
FT                   /note="Caffeic acid 3-O-methyltransferase 1"
FT                   /id="PRO_0000063207"
FT   REGION          162..180
FT                   /note="Substrate binding"
FT                   /evidence="ECO:0000250"
FT   ACT_SITE        269
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         130..136
FT                   /ligand="substrate"
FT                   /evidence="ECO:0000250"
FT   BINDING         208
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         231
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         251
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         252
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         265
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
SQ   SEQUENCE   365 AA;  39791 MW;  D6005B10FE55B83C CRC64;
     MGSTGETQMT PTQVSDEEAH LFAMQLASAS VLPMILKTAI ELDLLEIMAK AGPGAFLSTS
     EIASHLPTKN PDAPVMLDRI LRLLASYSIL TCSLKDLPDG KVERLYGLAP VCKFLTKNED
     GVSVSPLCLM NQDKVLMESW YYLKDAILEG GIPFNKAYGM TAFEYHGTDP RFNKVFNKGM
     SDHSTITMKK ILETYKGFEG LTSLVDVGGG TGAVVNTIVS KYPSIKGINF DLPHVIEDAP
     SYPGVEHVGG DMFVSVPNAD AVFMKWICHD WSDAHCLKFL KNCYDALPEN GKVILVECIL
     PVAPDTSLAT KGVVHVDVIM LAHNPGGKER TEKEFEGLAN GAGFQGFEVM CCAFNTHVIE
     FRKKA