Narayanan S J Jishnu, Bachhar Arnab, Tripathi Divya, Dutta Achintya Kumar
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai400076, India.
J Phys Chem A. 2023 Jan 19;127(2):457-467. doi: 10.1021/acs.jpca.2c07469.
We have analyzed the low-energy electron attachment to wobble base pairs using the equation of motion coupled cluster method and extended basis sets. A doorway mechanism exists for the attachment of the additional electron to the base pairs, where the initially formed dipole-bound anion captures the incoming electron. The doorway dipole-bound anionic state subsequently leads to the formation of a valence-bound state, and the transfer of extra electron occurs by mixing of electronic and nuclear degrees of freedom. The formation of the valence-bound anion is associated with proton transfer in hypoxanthine-cytosine and hypoxanthine-adenine base pairs, which happens through a concerted electron-proton transfer process. The calculated rate constant for the dipole-bound to valence-bound transition in wobble base pairs is slower than that observed in the Watson-Crick guanine-cytosine base pair.
我们使用运动方程耦合簇方法和扩展基组分析了低能电子与摆动碱基对的附着情况。存在一种门道机制，使得额外的电子附着到碱基对上，即最初形成的偶极束缚阴离子捕获入射电子。随后，门道偶极束缚阴离子态导致价态束缚态的形成，并且通过电子和核自由度的混合发生额外电子的转移。价态束缚阴离子的形成与次黄嘌呤 - 胞嘧啶和次黄嘌呤 - 腺嘌呤碱基对中的质子转移相关，这是通过协同的电子 - 质子转移过程发生的。计算得到的摆动碱基对偶极束缚到价态束缚转变的速率常数比在沃森 - 克里克鸟嘌呤 - 胞嘧啶碱基对中观察到的要慢。
