Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122, United States.
Institute for Computational Molecular Science, Temple University SERC, Philadelphia, Pennsylvania 19122, United States.
J Phys Chem A. 2021 Aug 19;125(32):6995-7003. doi: 10.1021/acs.jpca.1c05288. Epub 2021 Aug 4.
Electron attachment to DNA by low energy electrons can lead to DNA damage, so a fundamental understanding of how electrons interact with the components of nucleic acids in solution is an open challenge. In solution, low energy electrons can generate presolvated electrons, e, which are efficiently scavanged by pyrimidine nucleobases to form transient negative ions, able to relax to either stable valence bound anions or undergo dissociative electron detachment or transfer to other parts of DNA/RNA leading to strand breakages. In order to understand the initial electron attachment dynamics, this paper presents a joint molecular dynamics and high-level electronic structure study into the behavior of the electronic states of the solvated uracil anion. Both the valence π* and nonvalence e states of the solvated uracil system are studied, and the effect of the solvent environment and the geometric structure of the uracil core are uncoupled to gain insight into the physical origin of the stabilization of the solvated uracil anion. Solvent reorganization is found to play a dominant role followed by relaxation of the uracil core.
低能电子与 DNA 的电子附加作用可能导致 DNA 损伤，因此，深入了解电子在溶液中与核酸成分如何相互作用是一个尚未解决的问题。在溶液中，低能电子可以产生预溶剂化电子 e，它会被嘧啶核苷碱基有效地捕获，形成瞬态负离子，这些负离子可以弛豫到稳定的价态束缚阴离子，或者经历离解电子脱离，或者转移到 DNA/RNA 的其他部分，导致链断裂。为了理解初始电子附加动力学，本文提出了一种联合分子动力学和高级电子结构研究，以研究溶剂化尿嘧啶阴离子电子态的行为。本文研究了溶剂化尿嘧啶体系的价π*和非价 e 态，并解耦溶剂环境和尿嘧啶核心的几何结构，以深入了解溶剂化尿嘧啶阴离子稳定的物理起源。发现溶剂重组起着主导作用，随后是尿嘧啶核心的弛豫。
