OCR_BPT7
ID OCR_BPT7 Reviewed; 117 AA.
AC P03775;
DT 21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT 21-JUL-1986, sequence version 1.
DT 03-AUG-2022, entry version 102.
DE RecName: Full=Protein Ocr {ECO:0000303|PubMed:32483229};
DE AltName: Full=Gene product 0.3;
DE Short=Gp0.3;
DE AltName: Full=Overcome classical restriction;
DE Short=Ocr;
GN OrderedLocusNames=0.3;
OS Escherichia phage T7 (Bacteriophage T7).
OC Viruses; Duplodnaviria; Heunggongvirae; Uroviricota; Caudoviricetes;
OC Caudovirales; Autographiviridae; Studiervirinae; Teseptimavirus.
OX NCBI_TaxID=10760;
OH NCBI_TaxID=562; Escherichia coli.
RN [1]
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX PubMed=6864790; DOI=10.1016/s0022-2836(83)80282-4;
RA Dunn J.J., Studier F.W.;
RT "Complete nucleotide sequence of bacteriophage T7 DNA and the locations of
RT T7 genetic elements.";
RL J. Mol. Biol. 166:477-535(1983).
RN [2]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=7310871; DOI=10.1016/0022-2836(81)90178-9;
RA Dunn J.J., Studier F.W.;
RT "Nucleotide sequence from the genetic left end of bacteriophage T7 DNA to
RT the beginning of gene 4.";
RL J. Mol. Biol. 148:303-330(1981).
RN [3]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RA Korobko V.G., Chuvpilo S.A., Kolosov M.N.;
RT "Nucleotide sequence of gene 0.3 of bacteriophage T7.";
RL Bioorg. Khim. 6:1272-1274(1980).
RN [4]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX PubMed=7007389; DOI=10.1016/s0021-9258(19)69822-4;
RA Dunn J.J., Elzinga M., Mark K.-K., Studier F.W.;
RT "Amino acid sequence of the gene 0.3 protein of bacteriophage T7 and
RT nucleotide sequence of its mRNA.";
RL J. Biol. Chem. 256:2579-2585(1981).
RN [5]
RP SUBUNIT.
RX PubMed=6257722; DOI=10.1016/s0021-9258(19)69821-2;
RA Mark K.K., Studier F.W.;
RT "Purification of the gene 0.3 protein of bacteriophage T7, an inhibitor of
RT the DNA restriction system of Escherichia coli.";
RL J. Biol. Chem. 256:2573-2578(1981).
RN [6]
RP FUNCTION.
RX PubMed=1095770; DOI=10.1016/0022-2836(75)90083-2;
RA Studier F.W.;
RT "Gene 0.3 of bacteriophage T7 acts to overcome the DNA restriction system
RT of the host.";
RL J. Mol. Biol. 94:283-295(1975).
RN [7]
RP FUNCTION, INTERACTION WITH HOST HSDM, AND INTERACTION WITH HOST HSDR.
RX PubMed=12235377; DOI=10.1093/nar/gkf518;
RA Atanasiu C., Su T.J., Sturrock S.S., Dryden D.T.;
RT "Interaction of the ocr gene 0.3 protein of bacteriophage T7 with EcoKI
RT restriction/modification enzyme.";
RL Nucleic Acids Res. 30:3936-3944(2002).
RN [8]
RP FUNCTION, INTERACTION WITH HOST PGLX, AND MUTAGENESIS OF PHE-54 AND ALA-58.
RX PubMed=32338761; DOI=10.1093/nar/gkaa290;
RA Isaev A., Drobiazko A., Sierro N., Gordeeva J., Yosef I., Qimron U.,
RA Ivanov N.V., Severinov K.;
RT "Phage T7 DNA mimic protein Ocr is a potent inhibitor of BREX defence.";
RL Nucleic Acids Res. 48:5397-5406(2020).
RN [9] {ECO:0007744|PDB:1S7Z}
RP X-RAY CRYSTALLOGRAPHY (1.83 ANGSTROMS).
RX PubMed=11804597; DOI=10.1016/s1097-2765(02)00435-5;
RA Walkinshaw M.D., Taylor P., Sturrock S.S., Atanasiu C., Berge T.,
RA Henderson R.M., Edwardson J.M., Dryden D.T.;
RT "Structure of Ocr from bacteriophage T7, a protein that mimics B-form
RT DNA.";
RL Mol. Cell 9:187-194(2002).
RN [10] {ECO:0007744|PDB:2Y7C}
RP STRUCTURE BY ELECTRON MICROSCOPY (18.0 ANGSTROMS) OF 1-116 IN COMPLEX WITH
RP THE HOST TYPE I RESTRICTION-MODIFICATION METHYLASE COMPLEX ECOKI (M2S1),
RP AND INTERACTION WITH HOST HSDM.
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).
RN [11] {ECO:0007744|PDB:6R9B, ECO:0007744|PDB:6R9G}
RP STRUCTURE BY ELECTRON MICROSCOPY (3.70 ANGSTROMS), SUBUNIT, AND FUNCTION.
RX PubMed=32039758; DOI=10.7554/elife.52125;
RA Ye F., Kotta-Loizou I., Jovanovic M., Liu X., Dryden D.T., Buck M.,
RA Zhang X.;
RT "Structural basis of transcription inhibition by the DNA mimic protein Ocr
RT of bacteriophage T7.";
RL Elife 9:0-0(2020).
RN [12] {ECO:0007744|PDB:7BST, ECO:0007744|PDB:7BTP}
RP STRUCTURE BY ELECTRON MICROSCOPY (4.01 ANGSTROMS) IN COMPLEX WITH THE HOST
RP TYPE I RESTRICTION-MODIFICATION, FUNCTION, AND INTERACTION WITH HOST HSDR.
RX PubMed=32483229; DOI=10.1038/s41564-020-0731-z;
RA Gao Y., Cao D., Zhu J., Feng H., Luo X., Liu S., Yan X.X., Zhang X.,
RA Gao P.;
RT "Structural insights into assembly, operation and inhibition of a type I
RT restriction-modification system.";
RL Nat. Microbiol. 5:1107-1118(2020).
CC -!- FUNCTION: Prevents both degradation and modification of T7 DNA by the
CC host restriction-modification complex (PubMed:32039758,
CC PubMed:1095770). Structural mimic of the phosphate backbone of B-form
CC DNA that binds to and completely occupies the DNA-binding sites of all
CC known families of the complex type I DNA restriction enzymes
CC (PubMed:12235377, PubMed:32483229). Thereby, inhibits the restriction
CC endonuclease activity and protects the phage genome as it penetrates
CC into host cytoplasm (PubMed:12235377, PubMed:32483229). Inhibits host
CC transcription by binding to the bacterial RNAP and competing with sigma
CC factors (PubMed:32039758). Inhibits the host exclusion defense system
CC BREX (PubMed:32338761). {ECO:0000269|PubMed:1095770,
CC ECO:0000269|PubMed:12235377, ECO:0000269|PubMed:32039758,
CC ECO:0000269|PubMed:32338761, ECO:0000269|PubMed:32483229}.
CC -!- SUBUNIT: Homodimer (PubMed:32039758, PubMed:6257722). Interacts with
CC HsdM (AC P08957), the M subunit of host type I methyltransferase
CC restriction enzyme M.EcoKI; 1 Ocr dimer binds to M.EcoKI
CC (PubMed:12235377, PubMed:19074193). Interacts with HsdR (AC P08956),
CC the R subunit of host type I bifunctional endonuclease and
CC methyltransferase restriction enzyme R.EcoKI; 2 Ocr dimers binds to
CC R.EcoKI (PubMed:12235377, PubMed:32483229). Interacts with host
CC PglX/BrxX (AC P0DUF9); this interaction decreases by 20% the pglX-
CC mediated methylated sites required for self versus non-self
CC differentiation by the host (PubMed:32338761).
CC {ECO:0000269|PubMed:12235377, ECO:0000269|PubMed:19074193,
CC ECO:0000269|PubMed:32039758, ECO:0000269|PubMed:32338761,
CC ECO:0000269|PubMed:32483229, ECO:0000269|PubMed:6257722}.
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DR EMBL; M38334; AAA32564.1; -; Genomic_DNA.
DR EMBL; V01146; CAA24384.1; -; Genomic_DNA.
DR EMBL; V01127; CAA24327.1; -; Genomic_DNA.
DR PIR; A43002; W0BP37.
DR RefSeq; NP_041954.1; NC_001604.1.
DR PDB; 1S7Z; X-ray; 1.83 A; A=1-117.
DR PDB; 2Y7C; EM; 18.00 A; D/E=1-116.
DR PDB; 6R9B; EM; 3.80 A; F/G=1-117.
DR PDB; 6R9G; EM; 3.70 A; F/G=1-117.
DR PDB; 7BST; EM; 4.37 A; F/G=1-117.
DR PDB; 7BTP; EM; 4.01 A; D/F=1-117.
DR PDB; 7EEW; X-ray; 2.90 A; B=1-117.
DR PDBsum; 1S7Z; -.
DR PDBsum; 2Y7C; -.
DR PDBsum; 6R9B; -.
DR PDBsum; 6R9G; -.
DR PDBsum; 7BST; -.
DR PDBsum; 7BTP; -.
DR PDBsum; 7EEW; -.
DR SASBDB; P03775; -.
DR SMR; P03775; -.
DR IntAct; P03775; 1.
DR MINT; P03775; -.
DR GeneID; 1261063; -.
DR KEGG; vg:1261063; -.
DR EvolutionaryTrace; P03775; -.
DR Proteomes; UP000000840; Genome.
DR GO; GO:0099018; P:evasion by virus of host restriction-modification system; IEA:UniProtKB-KW.
DR Gene3D; 1.20.120.780; -; 1.
DR InterPro; IPR036207; B-form_Ocr.
DR InterPro; IPR014798; Ocr.
DR Pfam; PF08684; ocr; 1.
DR SUPFAM; SSF101059; SSF101059; 1.
PE 1: Evidence at protein level;
KW 3D-structure; Early protein; Host-virus interaction; Reference proteome;
KW Restriction-modification system evasion by virus.
FT CHAIN 1..117
FT /note="Protein Ocr"
FT /id="PRO_0000106462"
FT MUTAGEN 54
FT /note="F->D: Partial loss of inhibition of the host
FT exclusion defense system BREX; when associated with E-58."
FT /evidence="ECO:0000269|PubMed:32338761"
FT MUTAGEN 58
FT /note="A->E: Partial loss of inhibition of the host
FT exclusion defense system BREX; when associated with D-54."
FT /evidence="ECO:0000269|PubMed:32338761"
FT CONFLICT 43
FT /note="D -> S (in Ref. 3; AAA32564)"
FT /evidence="ECO:0000305"
FT HELIX 8..25
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 31..33
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 35..45
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 50..57
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 69..71
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 78..96
FT /evidence="ECO:0007829|PDB:1S7Z"
FT HELIX 98..106
FT /evidence="ECO:0007829|PDB:1S7Z"
SQ SEQUENCE 117 AA; 13809 MW; BB7D3D45068EB17D CRC64;
MAMSNMTYNN VFDHAYEMLK ENIRYDDIRD TDDLHDAIHM AADNAVPHYY ADIFSVMASE
GIDLEFEDSG LMPDTKDVIR ILQARIYEQL TIDLWEDAED LLNEYLEEVE EYEEDEE
