Structural Insight into Dynamic Bypass of the Major Cisplatin-DNA Adduct by Y-family Polymerase Dpo4

Authors

Jimson HY Wong, University of Western Ontario
Jessica A. Brown, The Ohio State University
Zucai Suo, The Ohio State University
Paul H. Blum, University of Nebraska-LincolnFollow
Takehiko Nohmi, National Institute of Health Sciences, Japan
Hong Ling, University of Western Ontario

Date of this Version

2010

Citation

The EMBO Journal 29 (2010), pp. 2059–2069.

doi:10.1038/ emboj.2010.101

Comments

Copyright © 2010 European Molecular Biology Organization.

Abstract

Y-family DNA polymerases bypass Pt-GG, the cisplatin-DNA double-base lesion, contributing to the cisplatin resistance in tumour cells. To reveal the mechanism, we determined three structures of the Y-family DNA polymerase, Dpo4, in complex with Pt-GG DNA. The crystallographic snapshots show three stages of lesion bypass: the nucleotide insertions opposite the 3´G (first insertion) and 5´G (second insertion) of Pt-GG, and the primer extension beyond the lesion site. We observed a dynamic process, in which the lesion was converted from an open and angular conformation at the first insertion to a depressed and nearly parallel conformation at the subsequent reaction stages to fit into the active site of Dpo4. The DNA translocation-coupled conformational change may account for additional inhibition on the second insertion reaction. The structures illustrate that Pt-GG disturbs the replicating base pair in the active site, which reduces the catalytic efficiency and fidelity. The in vivo relevance of Dpo4-mediated Pt-GG bypass was addressed by a dpo-4 knockout strain of Sulfolobus solfataricus, which exhibits enhanced sensitivity to cisplatin and proteomic alterations consistent with genomic stress.