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Structural insight into dynamic bypass of the major cisplatin‐DNA adduct by Y‐family polymerase Dpo4
Author(s) -
Wong Jimson HY,
Brown Jessica A,
Suo Zucai,
Blum Paul,
Nohmi Takehiko,
Ling Hong
Publication year - 2010
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2010.101
Subject(s) - biology , dna polymerase , polymerase , primer (cosmetics) , dna polymerase beta , dna clamp , dna , base pair , dna replication , dna damage , microbiology and biotechnology , biochemistry , gene , base excision repair , polymerase chain reaction , reverse transcriptase , chemistry , organic chemistry
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.