Narayanan S J Jishnu, Verma Pooja, Adhikary Amitava, Kumar Dutta Achintya
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India.
Department of Chemistry, Oakland University, 146 Library Drive, Rochester, Michigan, 48309, USA.
Chemphyschem. 2024 Dec 16;25(24):e202400581. doi: 10.1002/cphc.202400581. Epub 2024 Oct 30.
The cellular environment plays a significant role in low energy electron-mediated radiation damage to genetic materials. In this study, we have modeled the effect of the bulk medium on electron attachment to nucleobases in diethylene glycol (DEG) using uracil as a test case, in accordance with recent experimental work on the observation of dissociative quasi-free electron attachment to nucleoside via excited anion radical in solution (in DEG). Our EOM-CCSD-based quantum mechanical/molecular mechanical (QM/MM) simulations indicate that the electron scavenging by uracil in DEG is much slower than that observed in the aqueous medium due to its viscosity. This work also establishes that a doorway mechanism exists in uracil microsolvated and bulk solvated with DEG, with the dipole-bound state and solvent-bound state acting as doorway states, respectively.
细胞环境在低能电子介导的遗传物质辐射损伤中起着重要作用。在本研究中，我们以尿嘧啶为测试案例，根据最近关于在溶液（二甘醇中）通过激发阴离子自由基观察核苷的解离准自由电子附着的实验工作，模拟了本体介质对二甘醇（DEG）中电子附着到核碱基的影响。我们基于EOM - CCSD的量子力学/分子力学（QM/MM）模拟表明，由于二甘醇的粘度，尿嘧啶在其中的电子清除速度比在水介质中慢得多。这项工作还证实，在用二甘醇微溶剂化和本体溶剂化的尿嘧啶中存在一种门道机制，偶极束缚态和溶剂束缚态分别作为门道态。
