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首页> 外文期刊>Physical chemistry chemical physics: PCCP >One-electron oxidation of ds(5 '-GGG-3 ') and ds(5 '-G(8OG)G-3 ') and the nature of hole distribution: a density functional theory (DFT) study
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One-electron oxidation of ds(5 '-GGG-3 ') and ds(5 '-G(8OG)G-3 ') and the nature of hole distribution: a density functional theory (DFT) study

机译：DS（5'GGG-3'）和DS（5'-G（800g）G-3'）的单电子氧化和孔分布的性质：密度泛函理论（DFT）研究

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Of particular interest in radiation-induced charge transfer processes in DNA is the extent of hole localization immediately after ionization and subsequent relaxation. To address this, we considered double stranded oligomers containing guanine (G) and 8-oxoguanine (8OG), i.e., ds(5 '-GGG-3 ') and ds(5 '-G8OGG-3 ') in B-DNA conformation. Using DFT, we calculated a variety of properties, viz., vertical and adiabatic ionization potentials, spin density distributions in oxidized stacks, solvent and solute reorganization energies and one-electron oxidation potential (E-0) in the aqueous phase. Calculations for the vertical state of the -GGG- cation radical showed that the spin was found mainly (67%) on the middle G. However, upon relaxation to the adiabatic -GGG- cation radical, the spin localized (96%) on the 5 '-G, as observed in experiments. Hole localizations on the middle G and 3 '-G were higher in energy by 0.5 kcal mol(-1) and 0.4 kcal mol(-1), respectively, than that of 5 '-G. In the -G8OGG- cation radical, the spin localized only on the 8OG in both vertical and adiabatic states. The calculated vertical ionization potentials of -GGG- and -G8OGG- stacks were found to be lower than that of the vertical ionization potential of a single G in DNA. The calculated E-0 values of -GGG- and -G8OGG- stacks are 1.15 and 0.90 V, respectively, which owing to stacking effects are substantially lower than the corresponding experimental E-0 values of their monomers (1.49 and 1.18 V, respectively). SOMO to HOMO level switching is observed in these oxidized stacks. Consequently, our calculations predict that local double oxidations in DNA will form triplet diradical states, which are especially significant for high LET radiations.
机译：特别涉及DNA中的辐射诱导的电荷转移过程是电离后立即孔定位的程度和随后的松弛。为了解决这一点，我们将含有鸟嘌呤（G）和8-氧通（8-氧代），即DS（5'-GGG-3'）和DS（5'-GR8G-3'）的双链低聚物在B-DNA构象中进行。使用DFT，我们计算了各种性质，垂直和绝热电离电位，氧化堆叠中的旋转密度分布，溶剂和溶质重组能量和水相中的单电子氧化电位（E-0）。垂直状态的垂直状态的分析显示，旋转主要是在中间G上的（67％）。然而，在弛豫到绝热 - 凝聚的基团时，旋转局部（96％） 5'-g，如实验中所观察到。中间g和3'-g上的孔定位在能量下较高0.5kcal摩尔（-1）和0.4kcal摩尔（-1），而不是5'-g。在-G8阳离子中，旋转仅在垂直和绝热状态下局部定位。发现-GGG-和-G8Ogg-堆叠的计算的垂直电离电位低于DNA中单个G的垂直电离电位的垂直电离电位。计算出的-GGG-和-G8ogg-堆叠的E-0值分别为1.15和0.90V，由于堆叠效应基本上低于其单体的相应实验E-0值（分别为1.49和1.18V） 。在这些氧化堆叠中观察到SOMO到同性恋水平切换。因此，我们的计算预测DNA中的局部双氧化将形成三重态Diradical状态，这对于高允许辐射特别重要。

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