title: Error-Free Bypass of 7,8-dihydro-8-oxo-2'-deoxyguanosineby DNA Polymerase of Pseudomonas aeruginosa Phage PaP1.
abstract: As one of the most common forms of oxidative DNA damage, 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxoG) generally leads to G:C to T:A mutagenesis. To study DNA replication encountering 8-oxoG by the sole DNA polymerase (Gp90) ofPseudomonasaeruginosaphage PaP1, we performed steady-state and pre-steady-state kinetic analyses of nucleotide incorporation opposite 8-oxoG by Gp90 D234A that lacks exonuclease activities on ssDNA and dsDNA substrates. Gp90 D234A could bypass 8-oxoG in an error-free manner, preferentially incorporate dCTP opposite 8-oxoG, and yield similar misincorporation frequency to unmodified G. Gp90 D234A could extend beyond C:8-oxoG or A:8-oxoG base pairs with the same efficiency. dCTP incorporation opposite G and dCTP or dATP incorporation opposite 8-oxoG showed fast burst phases. The burst of incorporation efficiency (kpol/Kd,dNTP) is decreased as dCTP:G > dCTP:8-oxoG > dATP:8-oxoG. The presence of 8-oxoG in DNA does not affect its binding to Gp90 D234A in a binary complex but it does affect it in a ternary complex with dNTP and Mg2+, and dATP misincorporation opposite 8-oxoG further weakens the binding of Gp90 D234A to DNA. This study reveals Gp90 D234A can bypass 8-oxoG in an error-free manner, providing further understanding in DNA replication encountering oxidation lesion forP.aeruginosaphage PaP1.
authors.affiliation: College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China. shilinggu@foxmail.com.|Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China. shilinggu@foxmail.com.
authors.forename: Shiling
authors.initials: S
authors.lastname: Gu
authors.affiliation: Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China. xueqzhen@163.com.
authors.forename: Qizhen
authors.initials: Q
authors.lastname: Xue
authors.affiliation: College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China. liuqin@2014.cqut.edu.cn.
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China. xhmei2016@126.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Xiong
authors.affiliation: College of Pharmacy and Bioengineering, Chongqing University of Technology, No. 29 Hongguang Street, Banan District, Chongqing 400054, China. wannengw@cqut.cn.
authors.forename: Wanneng
authors.initials: W
authors.lastname: Wang
authors.affiliation: Public Health Laboratory Sciences and Toxicology, West China School of Public Health, Sichuan University, No. 17 People's South Road, Chengdu 610041, China. huidong.zhang@foxmail.com.
authors.forename: Huidong
authors.initials: H
authors.lastname: Zhang
keywords: 8-oxoG; DNA polymerase; P. aeruginosa phage PaP1; nucleotide incorporation; pre-steady-state kinetics; steady-state kinetics