Dynamics of Proofreading by the E. coli Pol III Replicase
نویسندگان
چکیده
منابع مشابه
Escherichia coli DNA polymerase IV (Pol IV), but not Pol II, dynamically switches with a stalled Pol III* replicase.
The dnaN159 allele encodes a temperature-sensitive mutant form of the β sliding clamp (β159). SOS-induced levels of DNA polymerase IV (Pol IV) confer UV sensitivity upon the dnaN159 strain, while levels of Pol IV ∼4-fold higher than those induced by the SOS response severely impede its growth. Here, we used mutations in Pol IV that disrupted specific interactions with the β clamp to test our hy...
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The dnaQ gene of Escherichia coli encodes the ε subunit of DNA polymerase III, which provides the 3' → 5' exonuclease proofreading activity of the replicative polymerase. Prior studies have shown that loss of ε leads to high mutation frequency, partially constitutive SOS, and poor growth. In addition, a previous study from our laboratory identified dnaQ knockout mutants in a screen for mutants ...
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The epsilon-subunit contains the catalytic site for the 3'-->5' proofreading exonuclease that functions in the DNA pol III (DNA polymerase III) core to edit nucleotides misinserted by the alpha-subunit DNA pol. A novel mutagenesis strategy was used to identify 23 dnaQ alleles that exhibit a mutator phenotype in vivo. Fourteen of the epsilon mutants were purified, and these proteins exhibited 3'...
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Processive DNA synthesis by the αεθ core of the Escherichia coli Pol III replicase requires it to be bound to the β2 clamp via a site in the α polymerase subunit. How the ε proofreading exonuclease subunit influences DNA synthesis by α was not previously understood. In this work, bulk assays of DNA replication were used to uncover a non-proofreading activity of ε. Combination of mutagenesis wit...
متن کاملSingle‐molecule mechanochemical characterization of E. coli pol III core catalytic activity
Pol III core is the three-subunit subassembly of the E. coli replicative DNA polymerase III holoenzyme. It contains the catalytic polymerase subunit α, the 3' → 5' proofreading exonuclease ε, and a subunit of unknown function, θ. We employ optical tweezers to characterize pol III core activity on a single DNA substrate. We observe polymerization at applied template forces F < 25 pN and exonucle...
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ژورنال
عنوان ژورنال: Cell Chemical Biology
سال: 2018
ISSN: 2451-9456
DOI: 10.1016/j.chembiol.2017.09.008