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Exploring the DNA mimicry of the Ocr protein of phage T7

DNA mimic proteins have evolved to control DNA-binding proteins by competing with the target DNA for binding to the protein. The Ocr protein of bacteriophage T7 is the most studied DNA mimic and functions to block the DNA-binding groove of Type I DNA restriction/modification enzymes. This binding pr...

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Autores principales: Roberts, Gareth A., Stephanou, Augoustinos S., Kanwar, Nisha, Dawson, Angela, Cooper, Laurie P., Chen, Kai, Nutley, Margaret, Cooper, Alan, Blakely, Garry W., Dryden, David T. F.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Oxford University Press 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439906/
https://www.ncbi.nlm.nih.gov/pubmed/22684506
http://dx.doi.org/10.1093/nar/gks516
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author Roberts, Gareth A.
Stephanou, Augoustinos S.
Kanwar, Nisha
Dawson, Angela
Cooper, Laurie P.
Chen, Kai
Nutley, Margaret
Cooper, Alan
Blakely, Garry W.
Dryden, David T. F.
author_facet Roberts, Gareth A.
Stephanou, Augoustinos S.
Kanwar, Nisha
Dawson, Angela
Cooper, Laurie P.
Chen, Kai
Nutley, Margaret
Cooper, Alan
Blakely, Garry W.
Dryden, David T. F.
author_sort Roberts, Gareth A.
collection PubMed
description DNA mimic proteins have evolved to control DNA-binding proteins by competing with the target DNA for binding to the protein. The Ocr protein of bacteriophage T7 is the most studied DNA mimic and functions to block the DNA-binding groove of Type I DNA restriction/modification enzymes. This binding prevents the enzyme from cleaving invading phage DNA. Each 116 amino acid monomer of the Ocr dimer has an unusual amino acid composition with 34 negatively charged side chains but only 6 positively charged side chains. Extensive mutagenesis of the charges of Ocr revealed a regression of Ocr activity from wild-type activity to partial activity then to variants inactive in antirestriction but deleterious for cell viability and lastly to totally inactive variants with no deleterious effect on cell viability. Throughout the mutagenesis the Ocr mutant proteins retained their folding. Our results show that the extreme bias in charged amino acids is not necessary for antirestriction activity but that less charged variants can affect cell viability by leading to restriction proficient but modification deficient cell phenotypes.
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spelling pubmed-34399062012-09-12 Exploring the DNA mimicry of the Ocr protein of phage T7 Roberts, Gareth A. Stephanou, Augoustinos S. Kanwar, Nisha Dawson, Angela Cooper, Laurie P. Chen, Kai Nutley, Margaret Cooper, Alan Blakely, Garry W. Dryden, David T. F. Nucleic Acids Res Structural Biology DNA mimic proteins have evolved to control DNA-binding proteins by competing with the target DNA for binding to the protein. The Ocr protein of bacteriophage T7 is the most studied DNA mimic and functions to block the DNA-binding groove of Type I DNA restriction/modification enzymes. This binding prevents the enzyme from cleaving invading phage DNA. Each 116 amino acid monomer of the Ocr dimer has an unusual amino acid composition with 34 negatively charged side chains but only 6 positively charged side chains. Extensive mutagenesis of the charges of Ocr revealed a regression of Ocr activity from wild-type activity to partial activity then to variants inactive in antirestriction but deleterious for cell viability and lastly to totally inactive variants with no deleterious effect on cell viability. Throughout the mutagenesis the Ocr mutant proteins retained their folding. Our results show that the extreme bias in charged amino acids is not necessary for antirestriction activity but that less charged variants can affect cell viability by leading to restriction proficient but modification deficient cell phenotypes. Oxford University Press 2012-09 2012-06-07 /pmc/articles/PMC3439906/ /pubmed/22684506 http://dx.doi.org/10.1093/nar/gks516 Text en © The Author(s) 2012. Published by Oxford University Press. http://creativecommons.org/licenses/by-nc/3.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Structural Biology
Roberts, Gareth A.
Stephanou, Augoustinos S.
Kanwar, Nisha
Dawson, Angela
Cooper, Laurie P.
Chen, Kai
Nutley, Margaret
Cooper, Alan
Blakely, Garry W.
Dryden, David T. F.
Exploring the DNA mimicry of the Ocr protein of phage T7
title Exploring the DNA mimicry of the Ocr protein of phage T7
title_full Exploring the DNA mimicry of the Ocr protein of phage T7
title_fullStr Exploring the DNA mimicry of the Ocr protein of phage T7
title_full_unstemmed Exploring the DNA mimicry of the Ocr protein of phage T7
title_short Exploring the DNA mimicry of the Ocr protein of phage T7
title_sort exploring the dna mimicry of the ocr protein of phage t7
topic Structural Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3439906/
https://www.ncbi.nlm.nih.gov/pubmed/22684506
http://dx.doi.org/10.1093/nar/gks516
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