Collision with duplex DNA renders Escherichia coli DNA polymerase III holoenzyme susceptible to DNA polymerase IV-mediated polymerase switching on the sliding clamp.

ABSTRACT: Organisms possess multiple DNA polymerases (Pols) and use each for a different purpose. One of the five Pols in Escherichia coli, DNA polymerase IV (Pol IV), encoded by the dinB gene, is known to participate in lesion bypass at certain DNA adducts. To understand how cells choose Pols when the replication fork encounters an obstacle on template DNA, the process of polymerase exchange from the primary replicative enzyme DNA polymerase III (Pol III) to Pol IV was studied in vitro. Replicating Pol III forming a tight holoenzyme (Pol III HE) with the sliding clamp was challenged by Pol IV on a primed ssDNA template carrying a short inverted repeat. A rapid and lesion-independent switch from Pol III to Pol IV occurred when Pol III HE encountered a hairpin stem duplex, implying that the loss of P

SUBMITTER: Le TT 

PROVIDER: S-EPMC5643309 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature