The mystery of sub-picosecond charge transfer following irradiation of hydrated uridine monophosphate.
The mystery of sub-picosecond charge transfer following irradiation of hydrated uridine monophosphate.
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水合尿苷单磷酸辐照后亚皮秒电荷转移的奥秘。
DOI：
10.1039/d0cp06482c
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
M. Mostafavi
中科院分区：
文献类型：
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作者：
A. de la Lande;S. Denisov;M. Mostafavi
电离射线通过所谓的直接效应破坏生物结构的早期机制在很大程度上是难以捉摸的。皮秒脉冲辐射解浓缩单磷酸尿苷的研究[J]。马，S. A.杰尼索夫，j.l。Marignier， P. Pernot， A. Adhikary， S. Seki和M. Mostafavi， J. Phys。化学。列托人。[j], 2018, 9,5105]，在核碱基氧化方面发现了意想不到的结果。在电子脉冲5 ps后，不能检测到氧化核碱基的特征，而只能检测到氧化的磷酸盐，这就提出了关于电荷转移机制的身份的有趣问题，可以解释U+的缺失。我们通过结合密度泛函理论（DFT）和极化嵌入方案，对溶剂化单磷酸尿苷进行先进的第一性原理原子模拟来解决这个问题。我们对比了三种非常不同的电荷转移机制，涵盖了atto，飞秒和皮秒时间尺度。在冻结核近似下，我们首先在阿秒到几飞秒的时间尺度上研究了电离机制和随后的空穴/电荷迁移。然后，我们考虑了核驱动的磷酸盐到氧化核碱基的电子转移，表明它在亚皮秒时间尺度上是一个非竞争性的反应通道，尽管它具有高放热性和显著的电子耦合。最后，我们证明非绝热电荷转移是由电离后的飞秒核弛豫实现的。我们发现电子退相干和电子耦合强度是决定跳频概率的关键参数。我们的结果提供了重要的见解，电子和核运动之间的相互作用，在早期阶段的多尺度反应的生物物质受到电离辐射。
The early mechanisms by which ionizing rays damage biological structures by so-called direct effects are largely elusive. In a recent picosecond pulse radiolysis study of concentrated uridine monophosphate solutions [J. Ma, S. A. Denisov, J.-L. Marignier, P. Pernot, A. Adhikary, S. Seki and M. Mostafavi, J. Phys. Chem. Lett., 2018, 9, 5105], unexpected results were found regarding the oxidation of the nucleobase. The signature of the oxidized nucleobase could not be detected 5 ps after the electron pulse, but only the oxidized phosphate, raising intriguing questions about the identity of charge-transfer mechanisms that could explain the absence of U+. We address here this question by means of advanced first-principles atomistic simulations of solvated uridine monophosphate, combining Density Functional Theory (DFT) with polarizable embedding schemes. We contrast three very distinct mechanisms of charge transfer covering the atto-, femto- and pico-second timescales. We first investigate the ionization mechanism and subsequent hole/charge migrations on a timescale of attoseconds to a few femtoseconds under the frozen nuclei approximation. We then consider a nuclear-driven phosphate-to-oxidized-nucleobase electron transfer, showing that it is an uncompetitive reaction channel on the sub-picosecond timescale, despite its high exothermicity and significant electronic coupling. Finally, we show that non-adiabatic charge transfer is enabled by femtosecond nuclear relaxation after ionization. We show that electronic decoherence and the electronic coupling strength are the key parameters that determine the hopping probabilities. Our results provide important insight into the interplay between electronics and nuclear motions in the early stages of the multiscale responses of biological matter subjected to ionizing radiation.