分子形貌半经验方法——快速预测Dpb的应用

C-H强弱在理解DNA和RNA的损坏机理中起着非常重要的作用,得到了许多学者们的关注.以3′,5′-二磷酸核酸为模型分子,应用分子形貌半经验理论方法,使用MELD精密从头计算及自编程序快速计算了8种化合物沿着C-H方向上的Dpb.通过分析沿着C-H方向上的Dpb,预测了化合物中C-H键的强弱,并获得了可能发生H-提取反应的活动顺序.通过计算DNA和RNA分子中糖基沿着C-H方向上的Dpb,预测发生H-提取反应难易程度的顺序分别为C1′-H>C2′-H>C4′-H>C5′-H>C3′-H和C1′-H>C4′-H>C5′-H>C3′-H>C2′-H.计算获得的Dpb数值表明,DNA和RNA中发生H-提取的位点都为C1′-H,预测的结果与文献中基本一致,可以为进一步研究相似体系中发生H-提取反应本质提供参考.

The application of semi-empirical molecular face method for quickly calculating the Dpb in situ

In order to understand the mechanical damage of DNA and RNA ,the knowledge of C -H bond strengths depicting the energy to form each chemical bond is needed .Therefore ,there are nu-merous papers focusing on this question .In the present study ,nucleoside 3′,5′-bisphosphates are cho-sen as model compounds for DNA and RNA .We calculated the Dpb of eight model compounds along C-H chemical bonds by the M ELD ab initio method and our ow n program ,and predicted the C-H bond strengths .The orders of H -abstraction in DNA and RNA were obtained .For instance ,the or-ders of H -abstraction in DNA and RNA are C1′-H＆gt; C2′-H＆gt;C4′-H＆gt;C5′-H＆gt; C3′-H and C1′-H＆gt;C4′-H＆gt;C5′-H＆gt;C3′-H＆gt;C2′-H respectively .T he orders render the C1′-H bond of DNA and RNA extraordinarily vulnerable to H -abstraction .The results that we obtained are almost agreement with those results previously reported .This work lays a foundation for future study of H -abstraction in similar systems .