接近0 eV的电子附着在核酸上
Jiande Gu1, Yaoming Xie, Henry F Schaefer
1Drug Design & Discovery Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Shanghai Institutes for Biological Sciences, CAS, PR China. hfs@uga.edu
Journal of the American Chemical Society
|January 26, 2006
概括
低能电子可以通过形成稳定的核酸基离子来启动DNA链断裂. 这些离子在基底有过多的电子密度,可以经历键断裂,导致链断裂.
科学领域:
- * 计算化学 计算化学
- * 分子建模 * 分子建模
- * 辐射化学 辐射化学
背景情况:
- * 了解低能电子对DNA损伤的初始步骤至关重要.
- *核酸是DNA的基本构建块,易受电子相互作用的影响.
研究的目的:
- * 研究由低能电子附着于核酸引起的DNA链断裂的机制.
- *使用理论计算来建模电子附着过程.
主要方法:
- *使用B3LYP/DZP++理论方法进行计算.
- *研究了对2'-脱氧基丁-3'-单酸盐 (3'-dCMPH) 和其去质子形式 (3'-dCMP(-) 的电子附着.
- *分析了气相和水相的基离子形成.
主要成果:
- *3'-dCMPH捕获接近0 eV的电子,形成一个稳定的基离子离子,基上有过多的电子密度.
- * 基于pyrimidine的基离子离子表现出高的电子脱离能,使得随后的C-O或糖化键裂变.
- *以酸盐为中心的基离子在水溶液中可能稳定,但在气相中可能不稳定.
结论:
- * 低能电子附着于核酸可以通过激素离子中间体导致DNA链断裂.
- * 核酸的电子亲和力不受水溶液中的对子离子的影响.
- *低于4 eV的事件电子可能无法有效地产生以酸盐为中心的基离子.
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