Singlet Oxygen Oxidation of the Radical Cations of 8-Oxo-2′-deoxyguanosine and Its 9-Methyl Analogue: Dynamics, Potential Energy Surface, and Products Mediated by C5-O2-Addition,ChemPlusChem

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Singlet Oxygen Oxidation of the Radical Cations of 8-Oxo-2′-deoxyguanosine and Its 9-Methyl Analogue: Dynamics, Potential Energy Surface, and Products Mediated by C5-O2-Addition
ChemPlusChem ( IF 3.0 ) Pub Date : 2021-07-06 , DOI: 10.1002/cplu.202100238
May Myat Moe _{1,

2} , Midas Tsai ₃ , Jianbo Liu _{1,

2}

Affiliation

8-Oxo-2′-deoxyguanosine (OG) is the most common DNA lesion. Notably, OG becomes more susceptible to oxidative damage than the undamaged nucleoside, forming mutagenic products in vivo. Herein the reactions of singlet O₂ with the radical cations of 8-oxo-2′-deoxyguanosine (OG^.+) and 9-methyl-8-oxoguanine (9MOG^.+) were investigated using ion-molecule scattering mass spectrometry, from which barrierless, exothermic O₂-addition products were detected for both reaction systems. Corroborated by static reaction potential energy surface constructed using multi-reference CASPT2 theory and molecular dynamics simulated in the presence of the reactants′ kinetic and internal energies, the C5-terminal O₂-addition was pinpointed as the most probable reaction pathway. By elucidating the reaction mechanism, kinetics and dynamics, and reaction products and energetics, this work constitutes the first report unraveling the synergetic damage of OG by ionizing radiation and singlet O₂.

中文翻译：

8-Oxo-2'-脱氧鸟苷及其 9-甲基类似物自由基阳离子的单线态氧氧化：动力学、势能表面和 C5-O2 加成介导的产物

8-Oxo-2'-deoxyguanosine (OG) 是最常见的 DNA 损伤。值得注意的是，OG 比未受损的核苷更容易受到氧化损伤，从而在体内形成诱变产物。本文使用离子分子散射质谱法研究了单线态 O ₂与自由基阳离子 8-oxo-2'-deoxyguanosine (OG ^.+ ) 和 9-methyl-8-oxoguanine (9MOG ^.+ ) 的反应，其中对两种反应系统都检测到了无屏障的放热O ₂加成产物。通过使用多参考 CASPT2 理论构建的静态反应势能表面和在反应物的动能和内能存在下模拟的分子动力学，C5-末端 O ₂-加成被确定为最可能的反应途径。通过阐明反应机理、动力学和动力学、反应产物和能量学，这项工作构成了第一个揭示OG通过电离辐射和单线态O ₂协同损伤的报告。

更新日期：2021-09-02

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