Structural highlights
Function
[V03_BPT7] Prevents both degradation and modification of T7 DNA by the host restriction-modification complex. Structural mimic of the phosphate backbone of B-form DNA that binds to and completely occupies the DNA-binding site of all type I restriction/modification enzymes. Thereby, inhibits the restriction endonuclease activity and protects the phage genome as it penetrates into host cytoplasm.[1] [2]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
We have solved, by X-ray crystallography to a resolution of 1.8 A, the structure of a protein capable of mimicking approximately 20 base pairs of B-form DNA. This ocr protein, encoded by gene 0.3 of bacteriophage T7, mimics the size and shape of a bent DNA molecule and the arrangement of negative charges along the phosphate backbone of B-form DNA. We also demonstrate that ocr is an efficient inhibitor in vivo of all known families of the complex type I DNA restriction enzymes. Using atomic force microscopy, we have also observed that type I enzymes induce a bend in DNA of similar magnitude to the bend in the ocr molecule. This first structure of an antirestriction protein demonstrates the construction of structural mimetics of long segments of B-form DNA.
Structure of Ocr from bacteriophage T7, a protein that mimics B-form DNA.,Walkinshaw MD, Taylor P, Sturrock SS, Atanasiu C, Berge T, Henderson RM, Edwardson JM, Dryden DT Mol Cell. 2002 Jan;9(1):187-94. PMID:11804597[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Studier FW. Gene 0.3 of bacteriophage T7 acts to overcome the DNA restriction system of the host. J Mol Biol. 1975 May 15;94(2):283-95. PMID:1095770
- ↑ Atanasiu C, Su TJ, Sturrock SS, Dryden DT. Interaction of the ocr gene 0.3 protein of bacteriophage T7 with EcoKI restriction/modification enzyme. Nucleic Acids Res. 2002 Sep 15;30(18):3936-44. PMID:12235377
- ↑ Walkinshaw MD, Taylor P, Sturrock SS, Atanasiu C, Berge T, Henderson RM, Edwardson JM, Dryden DT. Structure of Ocr from bacteriophage T7, a protein that mimics B-form DNA. Mol Cell. 2002 Jan;9(1):187-94. PMID:11804597
