ID   T1SD_ECOLX              Reviewed;         444 AA.
AC   P06991;
DT   01-APR-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1988, sequence version 1.
DT   25-MAY-2022, entry version 75.
DE   RecName: Full=Type I restriction enzyme EcoDI specificity subunit {ECO:0000305};
DE            Short=S protein;
DE   AltName: Full=Type I specificity subunit S.EcoDI {ECO:0000303|PubMed:12654995};
DE            Short=S.EcoDI {ECO:0000303|PubMed:12654995};
DE   AltName: Full=Type-1 restriction enzyme EcoDI specificity subunit;
GN   Name=hsdS {ECO:0000303|PubMed:6304321}; Synonyms=hss;
OS   Escherichia coli.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=562;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=D / E166;
RX   PubMed=6304321; DOI=10.1016/s0022-2836(83)80047-3;
RA   Gough J.A., Murray N.E.;
RT   "Sequence diversity among related genes for recognition of specific targets
RT   in DNA molecules.";
RL   J. Mol. Biol. 166:1-19(1983).
RN   [2]
RP   NOMENCLATURE.
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 specificity (S) subunit of a type I restriction enzyme;
CC       this subunit dictates DNA sequence specificity. The M and S subunits
CC       together form a methyltransferase (MTase) that methylates two adenine
CC       residues of the sequence 5'-TTAN(7)GTCY-3'. In the presence of the R
CC       subunit the complex can also act as an endonuclease, binding to the
CC       same target sequence but cutting the DNA some distance from this site.
CC       Whether the DNA is cut or modified depends on the methylation state of
CC       the target sequence. When the target site is unmodified, the DNA is
CC       cut. When the target site is hemimethylated, the complex acts as a
CC       maintenance MTase modifying the DNA so that both strands become
CC       methylated. After locating a non-methylated recognition site, the
CC       enzyme complex serves as a molecular motor that translocates DNA in an
CC       ATP-dependent manner until a collision occurs that triggers cleavage.
CC       {ECO:0000250|UniProtKB:P05719, ECO:0000303|PubMed:12654995}.
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:P05719}.
CC   -!- DOMAIN: Contains two DNA recognition domains, each specifying
CC       recognition of one of the two defined components of the target
CC       sequence. {ECO:0000250|UniProtKB:P05719}.
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:P05719}.
CC   -!- SIMILARITY: Belongs to the type-I restriction system S methylase
CC       family. {ECO:0000305}.
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DR   EMBL; V00287; CAA23553.1; -; Genomic_DNA.
DR   AlphaFoldDB; P06991; -.
DR   SMR; P06991; -.
DR   REBASE; 156147; S.BamRD77ORF2498P.
DR   REBASE; 191864; S.Apa1447ORF2453P.
DR   REBASE; 3640; S.EcoDI.
DR   PRO; PR:P06991; -.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0009307; P:DNA restriction-modification system; IEA:UniProtKB-KW.
DR   Gene3D; 3.90.220.20; -; 2.
DR   InterPro; IPR000055; Restrct_endonuc_typeI_TRD.
DR   InterPro; IPR044946; Restrct_endonuc_typeI_TRD_sf.
DR   Pfam; PF01420; Methylase_S; 2.
PE   3: Inferred from homology;
KW   DNA-binding; Restriction system.
FT   CHAIN           1..444
FT                   /note="Type I restriction enzyme EcoDI specificity subunit"
FT                   /id="PRO_0000198033"
SQ   SEQUENCE   444 AA;  49894 MW;  14BE17B5325294F0 CRC64;
     MSAGKLPVDW KTVELGELIK LSTGKLDANA ADNDGQYPFF TCAESVSQIN SWAFDTSAVL
     LAGNGSFSIK KYTGKFNAYQ RTYVIEPILI KTEFLYWLLR GNIKKITENG RGSTIPYIRK
     GDITDISVAL PSPSEQTLIA EKLDTLLAQV ESTKARLEQI PQILKRFRQA VLTFAMNGEL
     TKEWRSQNNN PAFFPAEKNS LKQFRNKELP SIPNNWSWMR FDQVADIASK LKSPLDYPNT
     IHLAPNHIES WTGKASGYQT ILEDGVTSAK HEFYTGQIIY SKIRPYLCKV TIATFDGMCS
     ADMYPINSKI DTHFLFRWML TNTFTDWASN AESRTVLPKI NQKDLSEIPV PTPPLPEQHE
     IVRRVEQLFA YADTIEKQVN NALARVNNLT QSILAKAFRG ELTAQWRAEN PDLISGENSA
     AALLEKIKAE RAASGGKKAS RKKS