Photo-activatable Ub-PCNA probes reveal new structural features of the Saccharomyces cerevisiae Polη/PCNA complex
Date
2021-08-14
Journal Title
Journal ISSN
Volume Title
Publisher
Nucleic Acids Research
Abstract
The Y-family DNA polymerase η (Polη) is critical for the synthesis past damaged DNA nucleotides in yeast through translesion DNA synthesis (TLS). TLS is initiated by monoubiquitination of proliferating cell nuclear antigen (PCNA) and the subsequent recruitment of TLS polymerases. Although individual structures of the Polη catalytic core and PCNA have been solved, a high-resolution structure of the complex of Polη/PCNA or Polη/monoubiquitinated PCNA (Ub-PCNA) still remains elusive, partly due to the disordered Polη C-terminal region and the flexibility of ubiquitin on PCNA. To circumvent these obstacles and obtain structural insights into this important TLS polymerase complex, we developed photo-activatable PCNA and Ub-PCNA probes containing a p-benzoyl-L-phenylalanine (pBpa) crosslinker at selected positions on PCNA. By photo-crosslinking the probes with full-length Polη, specific crosslinking sites were identified following tryptic digestion and tandem mass spectrometry analysis. We discovered direct interactions of the Polη catalytic core and its C-terminal region with both sides of the PCNA ring. Model building using the crosslinking site information as a restraint revealed multiple conformations of Polη in the polymerase complex. Availability of the photo-activatable PCNA and Ub-PCNA probes will also facilitate investigations into other PCNA-containing complexes important for DNA replication, repair and damage tolerance.
Description
This article has been accepted for publication in Nucleic Acids Research, Published by Oxford University Press. The version of record is available at: https://doi.org/10.1093/nar/gkab646
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Citation
Siqi Shen, Gregory A Davidson, Kun Yang, Zhihao Zhuang, Photo-activatable Ub-PCNA probes reveal new structural features of the Saccharomyces cerevisiae Polη/PCNA complex, Nucleic Acids Research, Volume 49, Issue 16, 20 September 2021, Pages 9374–9388, https://doi.org/10.1093/nar/gkab646