ID   T1SK_ECOLI              Reviewed;         464 AA.
AC   P05719; Q2M5W8;
DT   01-NOV-1988, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1988, sequence version 1.
DT   27-MAR-2024, entry version 159.
DE   RecName: Full=Type I restriction enzyme EcoKI specificity subunit {ECO:0000305};
DE            Short=S protein;
DE   AltName: Full=Type I specificity subunit S.EcoKI {ECO:0000303|PubMed:12654995};
DE            Short=S.EcoKI {ECO:0000303|PubMed:12654995};
DE   AltName: Full=Type-1 restriction enzyme EcoKI specificity subunit;
GN   Name=hsdS {ECO:0000303|PubMed:6255295}; Synonyms=hss;
GN   OrderedLocusNames=b4348, JW4311;
OS   Escherichia coli (strain K12).
OC   Bacteria; Pseudomonadota; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=83333;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND DOMAIN.
RC   STRAIN=K12;
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   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / MG1655 / ATCC 47076;
RX   PubMed=7610040; DOI=10.1093/nar/23.12.2105;
RA   Burland V.D., Plunkett G. III, Sofia H.J., Daniels D.L., Blattner F.R.;
RT   "Analysis of the Escherichia coli genome VI: DNA sequence of the region
RT   from 92.8 through 100 minutes.";
RL   Nucleic Acids Res. 23:2105-2119(1995).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / MG1655 / ATCC 47076;
RX   PubMed=9278503; DOI=10.1126/science.277.5331.1453;
RA   Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V.,
RA   Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F.,
RA   Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B.,
RA   Shao Y.;
RT   "The complete genome sequence of Escherichia coli K-12.";
RL   Science 277:1453-1462(1997).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911;
RX   PubMed=16738553; DOI=10.1038/msb4100049;
RA   Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S.,
RA   Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.;
RT   "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655
RT   and W3110.";
RL   Mol. Syst. Biol. 2:E1-E5(2006).
RN   [5]
RP   PROTEIN SEQUENCE OF 2-6, FUNCTION, AND SUBUNIT.
RC   STRAIN=K12;
RX   PubMed=8514761; DOI=10.1016/s0021-9258(19)38641-7;
RA   Dryden D.T., Cooper L.P., Murray N.E.;
RT   "Purification and characterization of the methyltransferase from the type 1
RT   restriction and modification system of Escherichia coli K12.";
RL   J. Biol. Chem. 268:13228-13236(1993).
RN   [6]
RP   PROTEIN SEQUENCE OF 2-35, AND DNA-BINDING.
RC   STRAIN=K12;
RX   PubMed=7739896; DOI=10.1093/nar/23.7.1177;
RA   Chen A., Powell L.M., Dryden D.T., Murray N.E., Brown T.;
RT   "Tyrosine 27 of the specificity polypeptide of EcoKI can be UV crosslinked
RT   to a bromodeoxyuridine-substituted DNA target sequence.";
RL   Nucleic Acids Res. 23:1177-1183(1995).
RN   [7]
RP   FUNCTION.
RC   STRAIN=K12;
RX   PubMed=4868368; DOI=10.1038/2171110a0;
RA   Meselson M., Yuan R.;
RT   "DNA restriction enzyme from E. coli.";
RL   Nature 217:1110-1114(1968).
RN   [8]
RP   FUNCTION, SUBUNIT, AND OPERON STRUCTURE.
RC   STRAIN=K12;
RX   PubMed=6255295; DOI=10.1007/bf00267350;
RA   Sain B., Murray N.E.;
RT   "The hsd (host specificity) genes of E. coli K 12.";
RL   Mol. Gen. Genet. 180:35-46(1980).
RN   [9]
RP   FUNCTION, AND SUBUNIT.
RC   STRAIN=K12;
RX   PubMed=9033396; DOI=10.1021/bi9619435;
RA   Dryden D.T., Cooper L.P., Thorpe P.H., Byron O.;
RT   "The in vitro assembly of the EcoKI type I DNA restriction/modification
RT   enzyme and its in vivo implications.";
RL   Biochemistry 36:1065-1076(1997).
RN   [10]
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).
RN   [11] {ECO:0007744|PDB:2Y7C, ECO:0007744|PDB:2Y7H}
RP   STRUCTURE BY ELECTRON MICROSCOPY (18.00 ANGSTROMS) IN COMPLEX WITH
RP   METHYLASE SUBUNIT AND ESCHERICHIA PHAGE T7 PROTEIN OCR.
RX   PubMed=19074193; DOI=10.1093/nar/gkn988;
RA   Kennaway C.K., Obarska-Kosinska A., White J.H., Tuszynska I., Cooper L.P.,
RA   Bujnicki J.M., Trinick J., Dryden D.T.;
RT   "The structure of M.EcoKI Type I DNA methyltransferase with a DNA mimic
RT   antirestriction protein.";
RL   Nucleic Acids Res. 37:762-770(2009).
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 A-2 on the
CC       top and A-3 on the bottom strand of the sequence 5'-AACN(6)GTGC-3'. In
CC       the presence of the R subunit the complex can also act as an
CC       endonuclease, binding to the same target sequence but cutting the DNA
CC       some distance from this site. Whether the DNA is cut or modified
CC       depends on the methylation state of the target sequence. When the
CC       target site is unmodified, the DNA is cut. When the target site is
CC       hemimethylated, the complex acts as a maintenance MTase modifying the
CC       DNA so that both strands become methylated. 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. {ECO:0000269|PubMed:4868368,
CC       ECO:0000269|PubMed:6255295, ECO:0000269|PubMed:8514761,
CC       ECO:0000269|PubMed:9033396}.
CC   -!- SUBUNIT: The type I restriction/modification system is composed of
CC       three polypeptides R, M and S (PubMed:6255295). The restriction enzyme
CC       has stoichiometry R(2)M(2)S(1) (PubMed:9033396). The methyltransferase
CC       is composed of M(2)S(1) (PubMed:8514761, PubMed:9033396,
CC       PubMed:19074193). {ECO:0000269|PubMed:19074193,
CC       ECO:0000269|PubMed:6255295, ECO:0000269|PubMed:8514761,
CC       ECO:0000269|PubMed:9033396}.
CC   -!- SUBUNIT: (Microbial infection) Interacts with Escherichia phage T7
CC       protein Ocr; this interaction leads to the inhibition of the
CC       methyltransferase restriction enzyme M.EcoKI composed of M(2)S(1).
CC       {ECO:0000269|PubMed:19074193}.
CC   -!- INDUCTION: Encoded in the hsd locus, in the order hsdR-hsdM-hsdS. There
CC       is a promoter upstream of hsdR and another between hsdR and hsdM
CC       (PubMed:6255295). This probably allows expression of the methylase
CC       enzyme before the restriction-specific subunit (Probable).
CC       {ECO:0000269|PubMed:6255295, ECO:0000305|PubMed:6255295}.
CC   -!- DOMAIN: Contains two DNA recognition domains, each specifying
CC       recognition of one of the two defined components of the target
CC       sequence. {ECO:0000305|PubMed:6304321}.
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:0000269|PubMed:4868368, ECO:0000269|PubMed:6255295,
CC       ECO:0000269|PubMed:8514761, ECO:0000269|PubMed:9033396}.
CC   -!- SIMILARITY: Belongs to the type-I restriction system S methylase
CC       family. {ECO:0000305}.
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DR   EMBL; V00288; CAA23554.1; -; Genomic_DNA.
DR   EMBL; U14003; AAA97245.1; -; Genomic_DNA.
DR   EMBL; U00096; AAC77304.1; -; Genomic_DNA.
DR   EMBL; AP009048; BAE78338.1; -; Genomic_DNA.
DR   PIR; A30369; NDECKS.
DR   RefSeq; NP_418768.1; NC_000913.3.
DR   RefSeq; WP_001272447.1; NZ_LN832404.1.
DR   PDB; 2Y7C; EM; 18.00 A; A=1-464.
DR   PDB; 2Y7H; EM; 18.00 A; A=1-464.
DR   PDBsum; 2Y7C; -.
DR   PDBsum; 2Y7H; -.
DR   AlphaFoldDB; P05719; -.
DR   SMR; P05719; -.
DR   BioGRID; 4262767; 128.
DR   ComplexPortal; CPX-5628; Type I restriction-modification EcoKI complex.
DR   DIP; DIP-9945N; -.
DR   IntAct; P05719; 12.
DR   STRING; 511145.b4348; -.
DR   REBASE; 13378; S.EcoW3110ORF4339P.
DR   REBASE; 3646; S.EcoKI.
DR   jPOST; P05719; -.
DR   PaxDb; 511145-b4348; -.
DR   EnsemblBacteria; AAC77304; AAC77304; b4348.
DR   GeneID; 948867; -.
DR   KEGG; ecj:JW4311; -.
DR   KEGG; eco:b4348; -.
DR   PATRIC; fig|1411691.4.peg.2338; -.
DR   EchoBASE; EB0455; -.
DR   eggNOG; COG0732; Bacteria.
DR   HOGENOM; CLU_021095_10_2_6; -.
DR   InParanoid; P05719; -.
DR   OMA; LPEGWCW; -.
DR   OrthoDB; 9798929at2; -.
DR   PhylomeDB; P05719; -.
DR   BioCyc; EcoCyc:EG10460-MONOMER; -.
DR   BioCyc; MetaCyc:EG10460-MONOMER; -.
DR   BRENDA; 3.1.21.3; 2165.
DR   EvolutionaryTrace; P05719; -.
DR   PRO; PR:P05719; -.
DR   Proteomes; UP000000318; Chromosome.
DR   Proteomes; UP000000625; Chromosome.
DR   GO; GO:0019812; C:type I site-specific deoxyribonuclease complex; IPI:ComplexPortal.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0009307; P:DNA restriction-modification system; IDA:ComplexPortal.
DR   CDD; cd17252; RMtype1_S_EcoKI-TRD1-CR1_like; 1.
DR   CDD; cd17261; RMtype1_S_EcoKI-TRD2-CR2_like; 1.
DR   Gene3D; 3.90.220.20; DNA methylase specificity domains; 2.
DR   InterPro; IPR000055; Restrct_endonuc_typeI_TRD.
DR   InterPro; IPR044946; Restrct_endonuc_typeI_TRD_sf.
DR   PANTHER; PTHR43140:SF1; TYPE I RESTRICTION ENZYME ECOKI SPECIFICITY SUBUNIT; 1.
DR   PANTHER; PTHR43140; TYPE-1 RESTRICTION ENZYME ECOKI SPECIFICITY PROTEIN; 1.
DR   Pfam; PF01420; Methylase_S; 2.
DR   SUPFAM; SSF116734; DNA methylase specificity domain; 2.
PE   1: Evidence at protein level;
KW   3D-structure; Direct protein sequencing; DNA-binding; Reference proteome;
KW   Restriction system.
FT   INIT_MET        1
FT                   /note="Removed"
FT                   /evidence="ECO:0000269|PubMed:7739896,
FT                   ECO:0000269|PubMed:8514761"
FT   CHAIN           2..464
FT                   /note="Type I restriction enzyme EcoKI specificity subunit"
FT                   /id="PRO_0000198035"
SQ   SEQUENCE   464 AA;  51395 MW;  1D651D0716B08C04 CRC64;
     MSAGKLPEGW VIAPVSTVTT LIRGVTYKKE QAINYLKDDY LPLIRANNIQ NGKFDTTDLV
     FVPKNLVKES QKISPEDIVI AMSSGSKSVV GKSAHQHLPF ECSFGAFCGV LRPEKLIFSG
     FIAHFTKSSL YRNKISSLSA GANINNIKPA SFDLINIPIP PLAEQKIIAE KLDTLLAQVD
     STKARFEQIP QILKRFRQAV LGGAVNGKLT EKWRNFEPQH SVFKKLNFES ILTELRNGLS
     SKPNESGVGH PILRISSVRA GHVDQNDIRF LECSESELNR HKLQDGDLLF TRYNGSLEFV
     GVCGLLKKLQ HQNLLYPDKL IRARLTKDAL PEYIEIFFSS PSARNAMMNC VKTTSGQKGI
     SGKDIKSQVV LLPPVKEQAE IVRRVEQLFA YADTIEKQVN NALARVNNLT QSILAKAFRG
     ELTAQWRAEN PDLISGENSA AALLEKIKAE RAASGGKKAS RKKS
//