Reconstitution of the Very Short Patch Repair Pathway from Escherichia coli |
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Authors: | Adam B Robertson Steven W Matson |
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Institution: | From the ‡Department of Biology and ;the §Curriculum in Genetics & Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599 |
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Abstract: | The Escherichia coli very short patch (VSP) repair pathway corrects thymidine-guanine mismatches that result from spontaneous hydrolytic deamination damage of 5-methyl cytosine. The VSP repair pathway requires the Vsr endonuclease, DNA polymerase I, a DNA ligase, MutS, and MutL to function at peak efficiency. The biochemical roles of most of these proteins in the VSP repair pathway have been studied extensively. However, these proteins have not been studied together in the context of VSP repair in an in vitro system. Using purified components of the VSP repair system in a reconstitution reaction, we have begun to develop an understanding of the role played by each of these proteins in the VSP repair pathway and have gained insights into their interactions. In this report we demonstrate an in vitro reconstitution of the VSP repair pathway using a plasmid DNA substrate. Surprisingly, the repair track length can be modulated by the concentration of DNA ligase. We propose roles for MutL and MutS in coordination of this repair pathway. |
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Keywords: | DNA Damage DNA Enzymes DNA Methylation DNA Mismatch Repair DNA Polymerase DNA Ligase MutL MutS VSR Endonuclease |
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