Cryo-EM structure of Pol κ-DNA-PCNA holoenzyme and implications for polymerase switching in DNA lesion bypass
Sobhy, Mohamed Abdelmaboud
Ragan, Timothy J.
De Biasio, Alfredo
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Laboratory of DNA Replication and Recombination
Permanent link to this recordhttp://hdl.handle.net/10754/664430
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AbstractReplacement of the stalled replicative polymerase (Pol δ) at a DNA lesion by the error-prone DNA polymerase κ (Pol κ) restarts synthesis past the lesion to prevent genome instability. The switching from Pol δ to Pol κ is mediated by the processivity clamp PCNA but the structural basis of this mechanism is unknown. We determined the Cryo-EM structures of human Pol κ-DNA-PCNA complex and of a stalled Pol δ-DNA-PCNA complex at 3.9 and 4.7 Å resolution, respectively. In Pol κ complex, the C-terminus of the PAD domain docks the catalytic core to one PCNA protomer in an angled orientation, bending the DNA exiting Pol κ active site through PCNA. In Pol δ complex, the DNA is disengaged from the active site but is retained by the thumb domain. We present a model for polymerase switching facilitated by Pol κ recruitment to PCNA and Pol κ conformational sampling to seize the DNA from stalled Pol δ assisted by PCNA tilting.
CitationLancey, C., Tehseen, M., Takahashi, M., Sobhy, M. A., Ragan, T. J., Crehuet, R., … De Biasio, A. (2020). Cryo-EM structure of Pol κ-DNA-PCNA holoenzyme and implications for polymerase switching in DNA lesion bypass. doi:10.1101/2020.07.10.196956
SponsorsThis research was supported by King Abdullah University of Science and Technology through core funding (to S.M.H.), and by the Wellcome Trust (to A.D.B.). R.C. acknowledges funding from the MINECO (CTQ2016-78636-P) and to AGAUR, (2017 SGR 324). The MD project has been carried out using CSUC resources. We acknowledge The Midlands Regional Cryo-EM Facility at the Leicester Institute of Structural and Chemical Biology (LISCB), major funding from MRC (MC_PC_17136). We thank Christos Savva (LISCB, University of Leicester) for his help in Cryo-EM data collection and advice on data processing.
PublisherCold Spring Harbor Laboratory