On the electron affinity of cytosine in bulk water and at hydrophobic aqueous interfaces
On the electron affinity of cytosine in bulk water and at hydrophobic aqueous interfaces
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DOI：
10.1007/s00894-014-2453-8
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发表时间：
2014-10
影响因子：
2.2
通讯作者：
E. Vöhringer-Martinez;Ciro Dörner;B. Abel
中科院分区：
文献类型：
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作者：
E. Vöhringer-Martinez;Ciro Dörner;B. Abel
在过去，大量水中DNA损伤的一种可能机制被归因于水中水合电子的存在。最近，水合电子的一个重要性质，即它们的结合能，被报道在疏水界面比在本体水溶液中更小。这可能开辟了新的反应可能性与不同的溶质，如DNA在疏水性，水界面。在这里，我们使用QM/MM分子动力学模拟研究如何在真空-水界面的分子环境，并在散装改变的DNA的特征部分胞嘧啶的电子亲和势。界面处的电子亲合势更接近部分水合电子的结合能，能量共振的增加使电子捕获过程更可能发生，表明疏水界面处的水合电子可能比完全水合的电子更活泼.此外，我们发现，电子附着后的阴离子形式的弛豫也诱导了质子从周围溶剂的转移，这是通过与实验还原电位的比较来证实的。图形摘要由中性形式的几何形状下的阴离子的单占据分子轨道表示的被胞嘧啶瞬时捕获后的过量电子的概率等密度面
In the past one possible mechanism of DNA damage in bulk water has been attributed to the presence of hydrated electrons in water. Recently, one important property of hydrated electrons, namely their binding energy, was reported to be smaller at hydrophobic interfaces than in bulk aqueous solution. This possibly opens up new reaction possibilities with different solutes such as the DNA at hydrophobic, aqueous interfaces. Here, we use QM/MM molecular dynamics simulation to study how the molecular environment at the vacuum-water interface and in the bulk alters the electron affinity of cytosine being a characteristic part of the DNA. The electron affinity at the interface is closer to the corresponding binding energy of the partially hydrated electron. The increased energy resonance makes the electron capture process more probable and suggests that hydrated electrons at hydrophobic interfaces may be more reactive than the fully hydrated ones. Additionally, we found that the relaxation of the anionic form after electron attachment also induces a proton transfer from the surrounding solvent that was confirmed by comparison with the experimental reduction potential.Graphical AbstractProbability isodensity surface of the excess electron after its instantaneous capture by cytosine represented by the single occupied molecular orbital of the anion at the geometry of the neutral form