Cryo-EM structure of human Pol κ bound to DNA and mono-ubiquitylated PCNA

Claudia Lancey, Muhammad Tehseen, Souvika Bakshi, Matthew Percival, Masateru Takahashi, Mohamed Abdelmaboud Sobhy, Vlad-Stefan Raducanu, Kerry Blair, Frederick W. Muskett, Timothy J. Ragan, Ramon Crehuet, Samir Hamdan, Alfredo De Biasio

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


AbstractY-family DNA polymerase κ (Pol κ) can replicate damaged DNA templates to rescue stalled replication forks. Access of Pol κ to DNA damage sites is facilitated by its interaction with the processivity clamp PCNA and is regulated by PCNA mono-ubiquitylation. Here, we present cryo-EM reconstructions of human Pol κ bound to DNA, an incoming nucleotide, and wild type or mono-ubiquitylated PCNA (Ub-PCNA). In both reconstructions, the internal PIP-box adjacent to the Pol κ Polymerase-Associated Domain (PAD) docks the catalytic core to one PCNA protomer in an angled orientation, bending the DNA exiting the Pol κ active site through PCNA, while Pol κ C-terminal domain containing two Ubiquitin Binding Zinc Fingers (UBZs) is invisible, in agreement with disorder predictions. The ubiquitin moieties are partly flexible and extend radially away from PCNA, with the ubiquitin at the Pol κ-bound protomer appearing more rigid. Activity assays suggest that, when the internal PIP-box interaction is lost, Pol κ is retained on DNA by a secondary interaction between the UBZs and the ubiquitins flexibly conjugated to PCNA. Our data provide a structural basis for the recruitment of a Y-family TLS polymerase to sites of DNA damage.
Original languageEnglish (US)
JournalNature Communications
Issue number1
StatePublished - Oct 19 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-10-21
Acknowledged KAUST grant number(s): CRG8 URF/1/4036-01-01
Acknowledgements: This research was supported by King Abdullah University of Science and Technology through core funding (to S.M.H.) and the Competitive Research Award Grant CRG8 URF/1/4036-01-01 (to S.M.H. and A.D.B.), 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

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Chemistry
  • General Physics and Astronomy


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