ID   T1M_SALPO               Reviewed;         529 AA.
AC   P07989;
DT   01-AUG-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1995, sequence version 2.
DT   29-MAY-2024, entry version 92.
DE   RecName: Full=Type I restriction enzyme StySPI methylase subunit;
DE            Short=M protein;
DE            EC=2.1.1.72 {ECO:0000250|UniProtKB:P08957};
DE   AltName: Full=Type I methyltransferase M.StySPI {ECO:0000303|PubMed:12654995};
DE            Short=M.StySPI {ECO:0000303|PubMed:12654995};
DE   AltName: Full=Type I restriction and modification system SP {ECO:0000303|PubMed:3025838};
GN   Name=hsdM {ECO:0000303|PubMed:3025838}; Synonyms=hsdT;
OS   Salmonella potsdam.
OC   Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Salmonella.
OX   NCBI_TaxID=597;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1409708; DOI=10.1073/pnas.89.20.9836;
RA   Sharp P.M., Kelleher J.E., Daniel A.S., Cowan G.M., Murray N.E.;
RT   "Roles of selection and recombination in the evolution of type I
RT   restriction-modification systems in enterobacteria.";
RL   Proc. Natl. Acad. Sci. U.S.A. 89:9836-9840(1992).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 455-529, AND FUNCTION.
RX   PubMed=3025838; DOI=10.1073/pnas.83.24.9368;
RA   Fuller-Pace F.V., Murray N.E.;
RT   "Two DNA recognition domains of the specificity polypeptides of a family of
RT   type I restriction enzymes.";
RL   Proc. Natl. Acad. Sci. U.S.A. 83:9368-9372(1986).
RN   [3]
RP   NOMENCLATURE, AND SUBTYPE.
RX   PubMed=12654995; DOI=10.1093/nar/gkg274;
RA   Roberts R.J., Belfort M., Bestor T., Bhagwat A.S., Bickle T.A.,
RA   Bitinaite J., Blumenthal R.M., Degtyarev S.K., Dryden D.T., Dybvig K.,
RA   Firman K., Gromova E.S., Gumport R.I., Halford S.E., Hattman S.,
RA   Heitman J., Hornby D.P., Janulaitis A., Jeltsch A., Josephsen J., Kiss A.,
RA   Klaenhammer T.R., Kobayashi I., Kong H., Krueger D.H., Lacks S.,
RA   Marinus M.G., Miyahara M., Morgan R.D., Murray N.E., Nagaraja V.,
RA   Piekarowicz A., Pingoud A., Raleigh E., Rao D.N., Reich N., Repin V.E.,
RA   Selker E.U., Shaw P.C., Stein D.C., Stoddard B.L., Szybalski W.,
RA   Trautner T.A., Van Etten J.L., Vitor J.M., Wilson G.G., Xu S.Y.;
RT   "A nomenclature for restriction enzymes, DNA methyltransferases, homing
RT   endonucleases and their genes.";
RL   Nucleic Acids Res. 31:1805-1812(2003).
CC   -!- FUNCTION: The subtype gamma methyltransferase (M) subunit of a type I
CC       restriction enzyme. The M and S subunits together form a
CC       methyltransferase (MTase) that methylates A-2 on the top strand and A-3
CC       on the bottom strand of the sequence 5'-AACN(6)GTRC-3'. In the presence
CC       of the R subunit the complex can also act as an endonuclease, binding
CC       to the same target sequence but cutting the DNA some distance from this
CC       site. Whether the DNA is cut or modified depends on the methylation
CC       state of the target sequence. When the target site is unmodified, the
CC       DNA is cut. When the target site is hemimethylated, the complex acts as
CC       a maintenance MTase modifying the DNA so that both strands become
CC       methylated (PubMed:12654995, PubMed:3025838). After locating a non-
CC       methylated recognition site, the enzyme complex serves as a molecular
CC       motor that translocates DNA in an ATP-dependent manner until a
CC       collision occurs that triggers cleavage (By similarity).
CC       {ECO:0000250|UniProtKB:P08957, ECO:0000269|PubMed:3025838,
CC       ECO:0000303|PubMed:12654995}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=a 2'-deoxyadenosine in DNA + S-adenosyl-L-methionine = an
CC         N(6)-methyl-2'-deoxyadenosine in DNA + H(+) + S-adenosyl-L-
CC         homocysteine; Xref=Rhea:RHEA:15197, Rhea:RHEA-COMP:12418, Rhea:RHEA-
CC         COMP:12419, ChEBI:CHEBI:15378, ChEBI:CHEBI:57856, ChEBI:CHEBI:59789,
CC         ChEBI:CHEBI:90615, ChEBI:CHEBI:90616; EC=2.1.1.72;
CC         Evidence={ECO:0000250|UniProtKB:P08957};
CC   -!- SUBUNIT: The type I restriction/modification system is composed of
CC       three polypeptides R, M and S; the restriction enzyme has stoichiometry
CC       R(2)M(2)S(1) while the methyltransferase is M(2)S(1).
CC       {ECO:0000250|UniProtKB:P08957}.
CC   -!- MISCELLANEOUS: Type I restriction and modification enzymes are complex,
CC       multifunctional systems which require ATP, S-adenosyl methionine and
CC       Mg(2+) as cofactors and, in addition to their endonucleolytic and
CC       methylase activities, are potent DNA-dependent ATPases.
CC       {ECO:0000250|UniProtKB:P08957}.
CC   -!- SIMILARITY: Belongs to the N(4)/N(6)-methyltransferase family.
CC       {ECO:0000305}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; L02507; AAA27143.1; -; Genomic_DNA.
DR   EMBL; M14984; AAA27144.1; -; Genomic_DNA.
DR   AlphaFoldDB; P07989; -.
DR   SMR; P07989; -.
DR   REBASE; 3518; M.StySPI.
DR   PRO; PR:P07989; -.
DR   GO; GO:0003677; F:DNA binding; IEA:InterPro.
DR   GO; GO:0008170; F:N-methyltransferase activity; IEA:InterPro.
DR   GO; GO:0009007; F:site-specific DNA-methyltransferase (adenine-specific) activity; IEA:UniProtKB-EC.
DR   GO; GO:0009307; P:DNA restriction-modification system; IEA:UniProtKB-KW.
DR   GO; GO:0032259; P:methylation; IEA:UniProtKB-KW.
DR   Gene3D; 1.20.1260.30; -; 1.
DR   Gene3D; 3.40.50.150; Vaccinia Virus protein VP39; 1.
DR   InterPro; IPR022749; D12N6_MeTrfase_N.
DR   InterPro; IPR003356; DNA_methylase_A-5.
DR   InterPro; IPR002052; DNA_methylase_N6_adenine_CS.
DR   InterPro; IPR029063; SAM-dependent_MTases_sf.
DR   InterPro; IPR038333; T1MK-like_N_sf.
DR   PANTHER; PTHR42933; SLR6095 PROTEIN; 1.
DR   PANTHER; PTHR42933:SF4; TYPE I RESTRICTION ENZYME ECOKI METHYLASE SUBUNIT; 1.
DR   Pfam; PF12161; HsdM_N; 1.
DR   Pfam; PF02384; N6_Mtase; 1.
DR   PRINTS; PR00507; N12N6MTFRASE.
DR   SUPFAM; SSF53335; S-adenosyl-L-methionine-dependent methyltransferases; 1.
DR   PROSITE; PS00092; N6_MTASE; 1.
PE   3: Inferred from homology;
KW   Methyltransferase; Restriction system; S-adenosyl-L-methionine;
KW   Transferase.
FT   CHAIN           1..529
FT                   /note="Type I restriction enzyme StySPI methylase subunit"
FT                   /id="PRO_0000088025"
FT   REGION          424..443
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        429..443
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         148..153
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000250|UniProtKB:Q89Z59"
FT   BINDING         178..180
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000250|UniProtKB:Q89Z59"
FT   BINDING         216
FT                   /ligand="S-adenosyl-L-methionine"
FT                   /ligand_id="ChEBI:CHEBI:59789"
FT                   /evidence="ECO:0000250|UniProtKB:Q89Z59"
SQ   SEQUENCE   529 AA;  58906 MW;  07895A9ADA4FA249 CRC64;
     MNNNDLVAKL WKLCDNLRDG GVSYQNYVNE LASLLFLKMC KETGQEADYL PEGYRWDDLK
     SRIGQEQLQF YRNLLVHLGA DEKKLVQAVF QNVNTTITQP KQLTELVSSM DSLDWYNGDH
     GKSRDDFGDM YEGLLQKNAN ETKSGAGQYF TPRPLIKTII HLLKPQPREV VQDPAAGTAG
     FLIEADRYVK SQTNDLDDLD GDAQDFQIKK AFVGLELVPG TRRLALMNCL LHDIEGNLDH
     GGAIRLGNTL GSDGENLPQA DIVATNPPFG SAAGTNITRT FVHPTSNKQL CFMQHIIETL
     PPGGRAAAVV PDNVLFEGGK GTDIRRDLMD KCHLHTILRL PTGIFYAQGV KTNVLFFTKG
     TVANPNQDKN CTDDVWVYDL RTNMPSFGKR TPFTEQHLQP FETVYGEDPH GLSPRTEGEW
     SFNAEESEVA DSEENKNADQ HQATSRWRKF SREWIRTAKS DSLDISWLKD KDSIDADSLP
     EPDVLAAEAM GELVQALGEL DALMRELGAG DEADAQRQLL EEAFGGVKA
//