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

Document Type

Article

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.