ID   MMT1_WOLBI              Reviewed;        1088 AA.
AC   Q9SWR3;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   02-SEP-2026, entry version 91.
DE   RecName: Full=Methionine S-methyltransferase;
DE            EC=2.1.1.12;
DE   AltName: Full=AdoMet:Met S-methyltransferase;
GN   Name=MMT1; Synonyms=MMT;
OS   Wollastonia biflora (Beach sunflower) (Wedelia biflora).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; campanulids; Asterales; Asteraceae; Asteroideae;
OC   Heliantheae alliance; Heliantheae; Wollastonia.
OX   NCBI_TaxID=101473;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 71-80; 162-196; 300-305;
RP   380-385; 421-445; 450-462; 531-555; 704-712; 804-821; 823-825 AND 932-948,
RP   AND FUNCTION.
RC   TISSUE=Leaf;
RX   PubMed=10449582; DOI=10.1105/tpc.11.8.1485;
RA   Bourgis F., Roje S., Nuccio M.L., Fisher D.B., Tarczynski M.C., Li C.,
RA   Herschbach C., Rennenberg H., Pimenta M.J., Shen T.-L., Gage D.A.,
RA   Hanson A.D.;
RT   "S-methylmethionine plays a major role in phloem sulfur transport and is
RT   synthesized by a novel type of methyltransferase.";
RL   Plant Cell 11:1485-1498(1999).
RN   [2]
RP   ENZYME ACTIVITY, SUBUNIT, AND BIOPHYSICOCHEMICAL PROPERTIES.
RX   PubMed=7673218; DOI=10.1074/jbc.270.38.22344;
RA   James F., Nolte K.D., Hanson A.D.;
RT   "Purification and properties of S-adenosyl-L-methionine:L-methionine S-
RT   methyltransferase from Wollastonia biflora leaves.";
RL   J. Biol. Chem. 270:22344-22350(1995).
RN   [3]
RP   SUBCELLULAR LOCATION.
RX   PubMed=12226341; DOI=10.1104/pp.111.4.965;
RA   Trossat C., Nolte K.D., Hanson A.D.;
RT   "Evidence that the pathway of dimethylsulfoniopropionate biosynthesis
RT   begins in the cytosol and ends in the chloroplast.";
RL   Plant Physiol. 111:965-973(1996).
CC   -!- FUNCTION: Catalyzes the S-methylmethionine (SMM) biosynthesis from
CC       adenosyl-L-homocysteine (AdoMet) and methionine. SMM biosynthesis (by
CC       MMT1) and degradation (by HMT-1, HMT-2 and HMT-3) constitute the SMM
CC       cycle in plants, which is probably required to achieve short term
CC       control of AdoMet level. Also able to catalyze the selenium-
CC       methylmethionine (SeMM) from AdoMet and selenium-methionine (SeMet).
CC       May play a role in phoem sulfur transport; such function is however not
CC       essential. {ECO:0000269|PubMed:10449582}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-methionine + S-adenosyl-L-methionine = S-methyl-L-methionine
CC         + S-adenosyl-L-homocysteine; Xref=Rhea:RHEA:13761, ChEBI:CHEBI:57844,
CC         ChEBI:CHEBI:57856, ChEBI:CHEBI:58252, ChEBI:CHEBI:59789; EC=2.1.1.12;
CC         Evidence={ECO:0000269|PubMed:7673218};
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       pH dependence:
CC         Optimum pH is 7.2. {ECO:0000269|PubMed:7673218};
CC   -!- SUBUNIT: Homotetramer. {ECO:0000269|PubMed:7673218}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000269|PubMed:12226341}.
CC   -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC       superfamily. {ECO:0000305}.
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DR   EMBL; AF137023; AAD49573.1; -; mRNA.
DR   AlphaFoldDB; Q9SWR3; -.
DR   SMR; Q9SWR3; -.
DR   BioCyc; MetaCyc:MONOMER-14235; -.
DR   SABIO-RK; Q9SWR3; -.
DR   GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell.
DR   GO; GO:0030732; F:methionine S-methyltransferase activity; IEA:UniProtKB-EC.
DR   GO; GO:0030170; F:pyridoxal phosphate binding; IEA:InterPro.
DR   CDD; cd02440; AdoMet_MTases; 1.
DR   Gene3D; 3.90.1150.10; Aspartate Aminotransferase, domain 1; 1.
DR   Gene3D; 3.40.640.10; Type I PLP-dependent aspartate aminotransferase-like (Major domain); 1.
DR   Gene3D; 3.40.50.150; Vaccinia Virus protein VP39; 1.
DR   InterPro; IPR004839; Aminotransferase_I/II_large.
DR   InterPro; IPR025779; Met_S-MeTrfase.
DR   InterPro; IPR015424; PyrdxlP-dep_Trfase.
DR   InterPro; IPR015421; PyrdxlP-dep_Trfase_major.
DR   InterPro; IPR015422; PyrdxlP-dep_Trfase_small.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   InterPro; IPR007848; Small_mtfrase_dom.
DR   PANTHER; PTHR47087; METHIONINE S-METHYLTRANSFERASE; 1.
DR   PANTHER; PTHR47087:SF1; METHIONINE S-METHYLTRANSFERASE; 1.
DR   Pfam; PF00155; Aminotran_1_2; 1.
DR   Pfam; PF05175; MTS; 1.
DR   SUPFAM; SSF53383; PLP-dependent transferases; 2.
DR   SUPFAM; SSF53335; S-adenosyl-L-methionine-dependent methyltransferases; 1.
DR   PROSITE; PS51555; SAM_MT12; 1.
PE   1: Evidence at protein level;
KW   Cytoplasm; Direct protein sequencing; Methyltransferase;
KW   S-adenosyl-L-methionine; Transferase.
FT   CHAIN           1..1088
FT                   /note="Methionine S-methyltransferase"
FT                   /id="PRO_0000204463"
SQ   SEQUENCE   1088 AA;  121565 MW;  594CC75C1C4FB616 CRC64;
     MAAVTGLYGS IDEFLNHCSQ SGDSAYSALR SLLERLEKPD TRTEARIFLA HLQKKLDNDG
     ASQRCLETYH FQIQDIYLDR NEGTGYQNRK KFTMMVIPSI FMPEDWSFTF YEGINRHPDS
     IFKDKTVAEL GCGNGWISIA IAEKWLPLKV YGLDINPRAV KISWINLYLN AFDEDGQPVY
     DSESKTLLDR VEFYESDLLS YCRDNHIELE RIVGCIPQIL NPNPDAMSKL VTENASEEFL
     HSLSNYCALQ GFVEDQFGLG LIARAVEEGI DVIKPMGIMI FNMGGRPGQG VCKRLFERRG
     LSVNKLWQTK ILQASDTDIS ALVEIEKNNP HRFEFFMGLV GDRPICARTA WAFGKACGRI
     SHALSVYSCQ LRHPNEVKKI FEFLKNGFHD ISNSLDLSFE DDSVADEKIP FLAYLAGVLK
     DGSRFPYEPP TGNKRFRDLI ASFMKTYHHV PLSTDNVAIF PSRATAIENS LRLFTPRLAI
     VEEHLTCNLP RQWLTSLEIE QTRDSKTPID GITVIEAPRQ SDLMIELIKK LKPQVVVTGI
     AQFEAVTSSA FEHLLRVTRE IGSRLFIDIS DQFELSSLPS SIGVLKYLAR TPLPSHAAII
     CGLLRNRVYT DLEVAFVISE EQTIFDALTR TVELLQGNTA LISQYYYGCL FHELLSFQIP
     DRRQTAEREA ENVEASDIDM IGFSSSAISV LSQSELSVRV TEKSSLLHMD VDQIFLPTPT
     PVKAAIFESF ARQNVTETEC DVTPILRQFI LNTWNFSVEH SAEFIYADFP LALFNKLVLC
     CIEEGGSLCM PAGSNGNYAA AAKFLNANIM SIPTEAEVGF KLTAKQLSSV LETVHKPWVY
     ISGPTINPTG LLYSNEEMKS LLTVCARYGA RTIIDTSFSG IKFNSQDWDG WNLDASLAGL
     TGNPSFSVCL LGGLFFKIPT GGLSYGFLVL KSGFLADSFR SSFSGLNKPH NTVRYTAKKL
     LELGEQKGNL TGAAQGQEKL LATRLKRLKE TLENCGWEVI EARGGVSVIA KPSAYLGKNI
     KLEKDGSTWV TKLDGTNIRE AMLRATGLCI NGPSWTGIPD YCRFTFALED GDFDRALDCI
     VKFNQLVK
//