ID   IMT1_MESCR              Reviewed;         365 AA.
AC   P45986;
DT   01-NOV-1995, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1995, sequence version 1.
DT   03-AUG-2022, entry version 88.
DE   RecName: Full=Inositol 4-methyltransferase;
DE            EC=2.1.1.129;
GN   Name=IMT1;
OS   Mesembryanthemum crystallinum (Common ice plant) (Cryophytum crystallinum).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   Caryophyllales; Aizoaceae; Mesembryanthemum;
OC   Mesembryanthemum subgen. Cryophytum.
OX   NCBI_TaxID=3544;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RC   TISSUE=Leaf;
RX   PubMed=1600940; DOI=10.1002/j.1460-2075.1992.tb05266.x;
RA   Vernon D.M., Bohnert H.J.;
RT   "A novel methyl transferase induced by osmotic stress in the facultative
RT   halophyte Mesembryanthemum crystallinum.";
RL   EMBO J. 11:2077-2085(1992).
RN   [2]
RP   NUCLEOTIDE SEQUENCE.
RX   PubMed=9880357; DOI=10.1104/pp.119.1.165;
RA   Nelson D.E., Koukoumanos M., Bohnert H.J.;
RT   "Myo-inositol-dependent sodium uptake in ice plant.";
RL   Plant Physiol. 119:165-172(1999).
RN   [3]
RP   PROTEIN SEQUENCE OF N-TERMINUS.
RX   PubMed=7574673; DOI=10.1006/abbi.1995.1450;
RA   Rammesmayer G., Pichorner H., Adams P., Jensen R.G., Bohnert H.J.;
RT   "Characterization of IMT1, myo-inositol O-methyltransferase, from
RT   Mesembryanthemum crystallinum.";
RL   Arch. Biochem. Biophys. 322:183-188(1995).
CC   -!- FUNCTION: Catalyzes the methylation of myo-inositol into ononitol (1D-
CC       4-O-methyl myo-inositol), the first step in the biosynthesis of the
CC       cyclic sugar pinitol which has osmoprotective properties.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=myo-inositol + S-adenosyl-L-methionine = 1D-4-O-methyl-myo-
CC         inositol + H(+) + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:23248,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:17268, ChEBI:CHEBI:18266,
CC         ChEBI:CHEBI:57856, ChEBI:CHEBI:59789; EC=2.1.1.129;
CC   -!- PATHWAY: Polyol metabolism; myo-inositol metabolism.
CC   -!- TISSUE SPECIFICITY: Leaves and roots. The levels found in the leaves
CC       are 25 times greater than in the roots.
CC   -!- INDUCTION: By salt (osmotic) stress.
CC   -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC       superfamily. Cation-independent O-methyltransferase family.
CC       {ECO:0000255|PROSITE-ProRule:PRU01020}.
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DR   EMBL; M87340; AAA33032.1; -; mRNA.
DR   EMBL; U63634; AAB05891.1; -; Genomic_DNA.
DR   PIR; S22696; S22696.
DR   AlphaFoldDB; P45986; -.
DR   SMR; P45986; -.
DR   KEGG; ag:AAA33032; -.
DR   BioCyc; MetaCyc:MON-16307; -.
DR   BRENDA; 2.1.1.129; 3238.
DR   UniPathway; UPA00914; -.
DR   GO; GO:0030787; F:inositol 4-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:0006020; P:inositol metabolic process; IEA:UniProtKB-UniPathway.
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   Direct protein sequencing; Methyltransferase; S-adenosyl-L-methionine;
KW   Stress response; Transferase.
FT   CHAIN           1..365
FT                   /note="Inositol 4-methyltransferase"
FT                   /id="PRO_0000084188"
FT   ACT_SITE        270
FT                   /note="Proton acceptor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
FT   BINDING         232
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01020"
SQ   SEQUENCE   365 AA;  40296 MW;  E52D2ECFE6ED2922 CRC64;
     MTTYTNGNYT QPKTLDKDEQ LAGLAVTLAN AAAFPMILKS AFELKILDIF SKAGEGVFVS
     TSEIASQIGA KNPNAPVLLD RMLRLLASHS VLTCKLQKGE GGSQRVYGPA PLCNYLASND
     GQGSLGPLLV LHHDKVMMES WFHLNDYILE GGVPFKRAHG MIQFDYTGTD ERFNHVFNQG
     MAHHTILVMK KLLDNYNGFN DVKVLVDVGG NIGVNVSMIV AKHTHIKGIN YDLPHVIADA
     PSYPGVEHVG GNMFESIPQA DAIFMKWVLH DWSDEHCVKI LNKCYESLAK GGKIILVESL
     IPVIPEDNLE SHMVFSLDCH TLVHNQGGKE RSKEDFEALA SKTGFSTVDV ICCAYDTWVM
     ELYKK