ID   HMT1_BRAOT              Reviewed;         326 AA.
AC   A4ZGQ8;
DT   31-MAY-2011, integrated into UniProtKB/Swiss-Prot.
DT   29-MAY-2007, sequence version 1.
DT   03-AUG-2022, entry version 36.
DE   RecName: Full=Homocysteine S-methyltransferase 1;
DE            Short=BoHMT1;
DE            EC=2.1.1.10;
GN   Name=HMT1;
OS   Brassica oleracea var. italica (Broccoli).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; malvids; Brassicales; Brassicaceae; Brassiceae; Brassica.
OX   NCBI_TaxID=36774;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], FUNCTION, CATALYTIC ACTIVITY,
RP   BIOPHYSICOCHEMICAL PROPERTIES, ACTIVITY REGULATION, TISSUE SPECIFICITY, AND
RP   INDUCTION BY SELENATE.
RC   STRAIN=cv. Green comet;
RX   PubMed=17391716; DOI=10.1016/j.phytochem.2007.02.007;
RA   Lyi S.M., Zhou X., Kochian L.V., Li L.;
RT   "Biochemical and molecular characterization of the homocysteine S-
RT   methyltransferase from broccoli (Brassica oleracea var. italica).";
RL   Phytochemistry 68:1112-1119(2007).
CC   -!- FUNCTION: Catalyzes methyl transfer from S-methylmethionine to
CC       homocysteine. The highest preference is for DL-homocysteine >> DL-
CC       cysteine. Has no selenocysteine methyltransferase activity.
CC       {ECO:0000269|PubMed:17391716}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=L-homocysteine + S-methyl-L-methionine = H(+) + 2 L-
CC         methionine; Xref=Rhea:RHEA:26337, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:57844, ChEBI:CHEBI:58199, ChEBI:CHEBI:58252; EC=2.1.1.10;
CC         Evidence={ECO:0000269|PubMed:17391716};
CC   -!- COFACTOR:
CC       Name=Zn(2+); Xref=ChEBI:CHEBI:29105;
CC         Evidence={ECO:0000255|PROSITE-ProRule:PRU00333};
CC   -!- ACTIVITY REGULATION: Inhibited by L-methionine.
CC       {ECO:0000269|PubMed:17391716}.
CC   -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC       Kinetic parameters:
CC         KM=72 uM for DL-homocysteine {ECO:0000269|PubMed:17391716};
CC       pH dependence:
CC         Optimum pH is 7.2. {ECO:0000269|PubMed:17391716};
CC   -!- TISSUE SPECIFICITY: Expressed in roots, young leaves, florets and
CC       flowers. Not detected in old leaves. {ECO:0000269|PubMed:17391716}.
CC   -!- INDUCTION: Not induced by selenate or selenite. Up-regulated by
CC       sulfate. Not affected by the status of methionine, s-methylmethionine
CC       or homocysteine, or by cadmium. {ECO:0000269|PubMed:17391716}.
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DR   EMBL; DQ679980; ABG74913.1; -; mRNA.
DR   AlphaFoldDB; A4ZGQ8; -.
DR   SMR; A4ZGQ8; -.
DR   BioCyc; MetaCyc:MON-15250; -.
DR   GO; GO:0047150; F:betaine-homocysteine S-methyltransferase activity; IEA:InterPro.
DR   GO; GO:0008898; F:S-adenosylmethionine-homocysteine S-methyltransferase activity; IDA:UniProtKB.
DR   GO; GO:0061627; F:S-methylmethionine-homocysteine S-methyltransferase activity; IEA:RHEA.
DR   GO; GO:0008270; F:zinc ion binding; IEA:InterPro.
DR   GO; GO:0009086; P:methionine biosynthetic process; IEA:InterPro.
DR   GO; GO:0032259; P:methylation; IDA:UniProtKB.
DR   Gene3D; 3.20.20.330; -; 1.
DR   InterPro; IPR017226; Betaine-hCys_S-MeTrfase_BHMT.
DR   InterPro; IPR003726; HCY_dom.
DR   InterPro; IPR036589; HCY_dom_sf.
DR   Pfam; PF02574; S-methyl_trans; 1.
DR   PIRSF; PIRSF037505; Betaine_HMT; 1.
DR   SUPFAM; SSF82282; SSF82282; 1.
DR   PROSITE; PS50970; HCY; 1.
PE   1: Evidence at protein level;
KW   Metal-binding; Methyltransferase; Transferase; Zinc.
FT   CHAIN           1..326
FT                   /note="Homocysteine S-methyltransferase 1"
FT                   /id="PRO_0000409376"
FT   DOMAIN          9..323
FT                   /note="Hcy-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         241
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         308
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
FT   BINDING         309
FT                   /ligand="Zn(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29105"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00333"
SQ   SEQUENCE   326 AA;  35817 MW;  E7B32300AE2FB4A2 CRC64;
     MGLEKKSALL EDLIEKCGGC AVVDGGFATQ LEIHGAAIND PLWSAVSLIK DPELIKRVHM
     EYLEAGADVV VTSSYQATIP GFLSRGLSME ESESLLQKSV KLAVEARDRF WDKVSKTSGH
     SYNRALVAAS IGSYGAYLAD GSEYSGSYGE DVSLDKLKDF HRRRIQVLVE ASPDLLAFET
     IPNKLEAQAC VELLEEENVQ IPAWICFTSV DGENAPSGES FQECLETLNK SNNICAVGIN
     CAPPQFMDNL IRKFSKLTQK AIVVYPNSGE VWDGKAKKWL PSQCFGDAEF EMFATKWRDL
     GAKLIGGCCR TTPSTIKAIS RDLKRR