Abstract

The most frequently recurring cancer-associated DNA polymerase ε (Pol ε) mutation is a P286R substitution in the exonuclease domain. While originally proposed to increase genome instability by disrupting exonucleolytic proofreading, the P286R variant was later found to be significantly more pathogenic than Pol ε proofreading deficiency per se. The mechanisms underlying its stronger impact remained unclear. Here we report the crystal structure of the yeast orthologue, Pol ε−P301R, complexed with DNA and an incoming dNTP. Structural changes in the protein are confined to the exonuclease domain, with R301 pointing towards the exonuclease site. Molecular dynamics simulations suggest that R301 interferes with DNA binding to the exonuclease site, an outcome not observed with the exonuclease-inactive Pol ε−D290A,E292A variant lacking the catalytic residues. These results reveal a distinct mechanism of exonuclease inactivation by the P301R substitution and a likely basis for its dramatically higher mutagenic and tumorigenic effects.

Mutations in the human POLE gene are associated with tumours with high mutational loads. Here the authors provide a structural rationale for the mutagenic activity of the cancer-associated DNA polymerase ε P286R variant.

Details

Title
Structural consequence of the most frequently recurring cancer-associated substitution in DNA polymerase ε
Author
Parkash Vimal 1   VIAFID ORCID Logo  ; Kulkarni Yashraj 2   VIAFID ORCID Logo  ; ter Beek Josy 1   VIAFID ORCID Logo  ; Shcherbakova, Polina V 3 ; Kamerlin Shina Caroline Lynn 2   VIAFID ORCID Logo  ; Johansson, Erik 1   VIAFID ORCID Logo 

 Umeå University, Department of Medical Biochemistry and Biophysics, Umeå, Sweden (GRID:grid.12650.30) (ISNI:0000 0001 1034 3451) 
 Uppsala University, Department of Chemistry - BMC, Uppsala, Sweden (GRID:grid.8993.b) (ISNI:0000 0004 1936 9457) 
 University of Nebraska Medical Center, Eppley Institute for Research in Cancer and Allied Diseases, Fred & Pamela Buffett Cancer Center, Omaha, USA (GRID:grid.266813.8) (ISNI:0000 0001 0666 4105) 
Publication year
2019
Publication date
Jan 2019
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
1914848135
Copyright
This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.