The oxidation mechanism and kinetics of 2′-deoxyguanosine by carbonate radical anion

• Published in: Chemical physics letters 2020-01, Vol.739, p.136982, Article 136982
• Main Authors: Wang, Yuyue, An, Ping, Li, Shujin, Zhou, Liping
• Format: Article
• Language: English
• Subjects: 2′-Deoxyguanosine; Carbonate radical anion; Density functional theory; Kinetics; Reaction mechanisms
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2019.136982

[Display omitted] •The oxidation mechanism of dGuo by CO3•− is studied using DFT for the first time.•The SEPT is the most favorable mechanism for dGuo oxidation by CO3•−.•The calculated rate constant of SEPT mechanism is 4.19 × 108 M−1 s−1.•CO3•− caused a nearly 3700-fold preference for base damage over sugar damage.•The dGuo(–H)N1• is major damage intermediate at initial oxidation of dGuo by CO3•−. The oxidation mechanism and kinetics of 2′-deoxyguanosine (dGuo) by carbonate radical anion (CO3•−) have been investigated at M06-2X/ma-TZVP//6-311G(d,p) level using SMD solvation model. The equilibrium geometries, energies and thermodynamic properties of all stationary points along the radical adduct formation, hydrogen transfer and sequential electron proton transfer (SEPT) mechanisms were calculated. The SEPT mechanism is the most favorable and its calculated rate constant is 4.19 × 108 M−1 s−1. The dGuo(–H)N1• radical is major damage intermediate and CO3•− causes an approximately 3700-fold preference for base damage over sugar damage at the initial oxidation of dGuo by CO3•−.