利用ABEEM/MM模型对气态丝氨酸和苏氨酸残基二肽分子构象的研究

应用ABEEM／MM浮动电荷模型（原子一键电负性均衡方法融合进分子力场）对气态丝氨酸和苏氨酸残基二肽分子构象进行了初步的研究，与经典的力场模型相比，该方法中的静电势包含了分子内和分子间的静电极化作用，以及分子内电荷转移影响，同时加入了化学键等非原子中心电荷位点，合理的体现了分子中的电荷分布。相对其他极化力场模型，该模型具有计算量较小的特点。结果表明：我们模型计算的两种二肽分子的构象能和关键二面角结构与从头计算结果符合得很好，优于其他力场模型。

Study of serine and threonine dipeptids conformations usung ABEEM/MM Model

The conformations of serine and threonine dipeptide in gas are explored using ABEEM/MM fluctuating model.The electrostatic potential is obtained from the fixed atomic-center charges for the classical force field.In the ABEEM/MM model,compared to the classical force field,the partial charges are allowed to fluctuate in the same molecule in response to the environment.In order to describe the charge population reasonably,the important non-atomic-center charge sites(chemical bond and lone pair)are added into this model.The CPU time is not increased larger than other polarized force field.The conformational energy and structures calculated by this model are in good agreement with the corresponding ab initio results.The results from the ABEEM/MM model present higher accuracy than other force fields.