论文部分内容阅读
采用密度泛函理论,将基于能量的分子片方法(GEBF)应用于气相中优化B型脱氧核糖核酸(碱基对数目N=2,5,10)双螺旋构型的结构.通过比较M06-2X泛函和其他方法(B3LYP、B3LYP-vd W和TPSS泛函)的结果,发现不考虑碱基之间的π-π堆积作用将会导致碱基之间的纵向距离拉长.随着体系双螺旋链长的增加,没有考虑碱基堆积作用而导致的相邻碱基纵向距离拉长的程度快速衰减.计算表明,气相中B-DNA双螺旋结构的稳定性来源于其作用力(主要是氢键和π-π堆积作用)的协同性,对不多于10组碱基对的体系而言,其氢键的贡献明显大于碱基堆积作用.
The energy-based molecular-plate method (GEBF) was applied to optimize the structure of the B-type DNA with N = 2, 5 and 10 double helix conformations in the gas phase by using density functional theory. 2X function and other methods (B3LYP, B3LYP-vd W and TPSS functional), it was found that regardless of the π-π stacking between bases, the longitudinal distance between bases will be elongated. As the system The increase of the length of the double helix quickly decayed without increasing the elongation of the adjacent base due to the stacking of the bases.The calculated results show that the stability of the B-DNA double helix in the gas phase comes from its force Is a hydrogen bond and a π-π stacking effect) synergistic, for no more than 10 pairs of base pairs of the system, the contribution of hydrogen bonding was significantly greater than the base stacking effect.