1. Exchange between Escherichia coli polymerases II and III on a processivity clamp.
- Author
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Kath JE, Chang S, Scotland MK, Wilbertz JH, Jergic S, Dixon NE, Sutton MD, and Loparo JJ
- Subjects
- DNA genetics, DNA Damage genetics, DNA Polymerase II chemistry, DNA Polymerase III chemistry, DNA Polymerase beta chemistry, DNA Repair genetics, DNA Replication genetics, Escherichia coli enzymology, Escherichia coli genetics, Multiprotein Complexes chemistry, Multiprotein Complexes genetics, Protein Structure, Tertiary, DNA biosynthesis, DNA Polymerase II genetics, DNA Polymerase III genetics, DNA Polymerase beta genetics
- Abstract
Escherichia coli has three DNA polymerases implicated in the bypass of DNA damage, a process called translesion synthesis (TLS) that alleviates replication stalling. Although these polymerases are specialized for different DNA lesions, it is unclear if they interact differently with the replication machinery. Of the three, DNA polymerase (Pol) II remains the most enigmatic. Here we report a stable ternary complex of Pol II, the replicative polymerase Pol III core complex and the dimeric processivity clamp, β. Single-molecule experiments reveal that the interactions of Pol II and Pol III with β allow for rapid exchange during DNA synthesis. As with another TLS polymerase, Pol IV, increasing concentrations of Pol II displace the Pol III core during DNA synthesis in a minimal reconstitution of primer extension. However, in contrast to Pol IV, Pol II is inefficient at disrupting rolling-circle synthesis by the fully reconstituted Pol III replisome. Together, these data suggest a β-mediated mechanism of exchange between Pol II and Pol III that occurs outside the replication fork., (© The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.)
- Published
- 2016
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