ID   MMT1_MAIZE              Reviewed;        1091 AA.
AC   Q8W519; Q9XFH6;
DT   19-JUL-2004, integrated into UniProtKB/Swiss-Prot.
DT   19-JUL-2004, sequence version 2.
DT   03-AUG-2022, entry version 100.
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   Zea mays (Maize).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; Liliopsida; Poales; Poaceae; PACMAD clade;
OC   Panicoideae; Andropogonodae; Andropogoneae; Tripsacinae; Zea.
OX   NCBI_TaxID=4577;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=10449582; DOI=10.2307/3870977;
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   NUCLEOTIDE SEQUENCE [MRNA] OF 520-611.
RA   Wang H., Bohnert H.;
RT   "Plant one-carbon genes.";
RL   Submitted (OCT-2001) to the EMBL/GenBank/DDBJ databases.
RN   [3]
RP   PROBABLE FUNCTION OF SMM CYCLE.
RX   PubMed=12692340; DOI=10.1104/pp.102.018846;
RA   Kocsis M.G., Ranocha P., Gage D.A., Simon E.S., Rhodes D., Peel G.J.,
RA   Mellema S., Saito K., Awazuhara M., Li C., Meeley R.B., Tarczynski M.C.,
RA   Wagner C., Hanson A.D.;
RT   "Insertional inactivation of the methionine s-methyltransferase gene
RT   eliminates the s-methylmethionine cycle and increases the methylation
RT   ratio.";
RL   Plant Physiol. 131:1808-1815(2003).
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.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-methionine + S-adenosyl-L-methionine = S-adenosyl-L-
CC         homocysteine + S-methyl-L-methionine; Xref=Rhea:RHEA:13761,
CC         ChEBI:CHEBI:57844, ChEBI:CHEBI:57856, ChEBI:CHEBI:58252,
CC         ChEBI:CHEBI:59789; EC=2.1.1.12;
CC   -!- SUBUNIT: Homotetramer. {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the class I-like SAM-binding methyltransferase
CC       superfamily. {ECO:0000305}.
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DR   EMBL; AF144079; AAD34585.2; -; mRNA.
DR   EMBL; AF439733; AAL33599.1; -; mRNA.
DR   RefSeq; NP_001104941.2; NM_001111471.2.
DR   STRING; 4577.GRMZM2G098039_P01; -.
DR   PaxDb; Q8W519; -.
DR   GeneID; 541786; -.
DR   KEGG; zma:541786; -.
DR   eggNOG; ENOG502QS81; Eukaryota.
DR   Proteomes; UP000007305; Unplaced.
DR   ExpressionAtlas; Q8W519; baseline and differential.
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   GO; GO:0009058; P:biosynthetic process; IEA:InterPro.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   Gene3D; 3.40.50.150; -; 1.
DR   Gene3D; 3.40.640.10; -; 1.
DR   InterPro; IPR004839; Aminotransferase_I/II.
DR   InterPro; IPR025779; Met_S-MeTrfase.
DR   InterPro; IPR025714; Methyltranfer_dom.
DR   InterPro; IPR015424; PyrdxlP-dep_Trfase.
DR   InterPro; IPR015421; PyrdxlP-dep_Trfase_major.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   Pfam; PF00155; Aminotran_1_2; 1.
DR   Pfam; PF13847; Methyltransf_31; 1.
DR   SUPFAM; SSF53335; SSF53335; 1.
DR   SUPFAM; SSF53383; SSF53383; 2.
DR   PROSITE; PS51555; SAM_MT12; 1.
PE   2: Evidence at transcript level;
KW   Cytoplasm; Methyltransferase; Reference proteome; S-adenosyl-L-methionine;
KW   Transferase.
FT   CHAIN           1..1091
FT                   /note="Methionine S-methyltransferase"
FT                   /id="PRO_0000204462"
FT   CONFLICT        524..525
FT                   /note="LI -> MV (in Ref. 2; AAL33599)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        609..611
FT                   /note="YSD -> ITS (in Ref. 2; AAL33599)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   1091 AA;  120309 MW;  81A11D882CC4A5F8 CRC64;
     MAALAGEDKD VDAFLADCTA SGDAAYGAAK AVLERLHAPA TRPAARRLLG AVRRRFAASR
     AAGEDCFRTF HFRIHDVVLD PHVQGFQQMK KLTMMEIPSI FIPEDWSFTF YEGLNRHPDS
     IFRDKTVAEL GCGNGWISIA LAEKWCPSKV YGLDINPRAV KIAWINLYLN ALDDDGLPIY
     DGEGKTLLDR VEFYESDLLS YCRDNKIELD RIVGCIPQIL NPNPEAMSKI VTENSSEEFL
     YALSNYCALQ GFVEDQFGLG LIARAVEEGI SVIKPSGIMV FNMGGRPGQG VCERLFRRRG
     FRITKLWQTK IMQXADTDIS ALVEXEKNSR HRFEFFMDLV GBQPICARTA WAYMKSGGHI
     SHALSVYSCQ LRQPNQVKKI FEFLKDGFHE VSSSLDLSFD DDSVAEEKIP FLAYLASFLK
     ENKSNPCEPP AGCLNFRKLV AGFMKSYHHI PLTPDNVVVF PSRSVAIENA LQLFSPALAI
     VDEHLTRHLP KQWLTSLAIE GRADCNHADG TVTVIEAPRQ SDLLIELIRK LQPQVVVTGM
     AQFEAITSAA FENLLNVTKD VGSRLFLDIS EHLELSSLPS SNGVLKYLAG KTLPSHAAIL
     CGLVKNQVYS DLEVAFAISE DAAVYKALSQ TIELLEGHTS LISQHYYGCL FHELLAFQIA
     DRHPQQERQP AEVIPQQMIG FSDPAVSTLK ATEFFVPGSA ESSIIHMDLD RSFLPVPSAV
     NASVFESFVR QNITDSETDV RSSIQQLVKD SYGLSAAGCA EIIYGNTSVA LFNKLVLCCM
     QEQGTLLFPL GTNGHYVSAA KFVNASTVTI PTNPSSGFRI EPKVLADTLK NVSRPWVYVC
     GPTINPTGFL YSDSDIRELL SVCAEYGARV VIDTSFSGLE YETDGWRQWN LAGCLSSLKR
     SEPSFSVVLL GELSFALTAG GHDFGFVILG DSSLAETFHS FSSLSRPHTT LKYTFKKLLG
     LKNQKDQHFS DLIVEQKEEL KNRANQLIQT LESCGWEAAI GCGGISMLAK PTAYMGKAFK
     AAGFDGELDA SNIREAILRA TGLCINSSSW TGIPGYCRFS FALERGEFER AMGCIARFKE
     LVLGGAQMNG A