Electron-Induced Repair of 2'-Deoxyribose Sugar Radicals in DNA: A Density Functional Theory (DFT) Study.
Electron-Induced Repair of 2'-Deoxyribose Sugar Radicals in DNA: A Density Functional Theory (DFT) Study.
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DOI：
10.3390/ijms22041736
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发表时间：
2021-02-09
影响因子：
5.6
通讯作者：
Sevilla MD
中科院分区：
文献类型：
--
作者：
Bell M;Kumar A;Sevilla MD
在这项工作中，我们以 2′-脱氧鸟苷和 2′-脱氧胸苷为 DNA 模型，使用 ωB97XD 密度泛函和 6-31++G** 基组来研究水相中 2′-脱氧核糖自由基的结构、电子亲和力、玻尔兹曼分布的群体以及单电子还原电位 (E°)。计算预测糖自由基的相对稳定性顺序为C4′• > C1′• > C5′• > C3′• > C2′•。基于糖自由基相对稳定性的玻尔兹曼分布群体不是电离辐射或 OH 自由基攻击所发现的，并且是驱动形成产物的过程的动力学机制的良好证据。这些糖自由基的绝热电子亲和势在 2.6-3.3 eV 范围内，高于典型的 DNA 碱基。无质子化的糖自由基还原电位（E°）（-1.8至-1.2 V）也显着高于碱基。因此，糖自由基比 DNA 碱基更容易被溶剂化电子还原。在水相中，这些单电子还原糖自由基（阴离子）从溶剂中质子化，从而通过“电子诱导质子转移机制”有效修复。计算表明，与通过电子诱导质子转移机制对糖自由基的有效修复相比，环嘌呤损伤5',8-cyclo-2'-dG的修复将涉及相当大的屏障。
In this work, we used ωB97XD density functional and 6-31++G** basis set to study the structure, electron affinity, populations via Boltzmann distribution, and one-electron reduction potentials (E°) of 2′-deoxyribose sugar radicals in aqueous phase by considering 2′-deoxyguanosine and 2′-deoxythymidine as a model of DNA. The calculation predicted the relative stability of sugar radicals in the order C4′• > C1′• > C5′• > C3′• > C2′•. The Boltzmann distribution populations based on the relative stability of the sugar radicals were not those found for ionizing radiation or OH-radical attack and are good evidence the kinetic mechanisms of the processes drive the products formed. The adiabatic electron affinities of these sugar radicals were in the range 2.6–3.3 eV which is higher than the canonical DNA bases. The sugar radicals reduction potentials (E°) without protonation (−1.8 to −1.2 V) were also significantly higher than the bases. Thus the sugar radicals will be far more readily reduced by solvated electrons than the DNA bases. In the aqueous phase, these one-electron reduced sugar radicals (anions) are protonated from solvent and thus are efficiently repaired via the “electron-induced proton transfer mechanism”. The calculation shows that, in comparison to efficient repair of sugar radicals by the electron-induced proton transfer mechanism, the repair of the cyclopurine lesion, 5′,8-cyclo-2′-dG, would involve a substantial barrier.
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影响因子：
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作者：
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