组氨酸二肽-水团簇的Ab Initio和ABEEMσπ力场的研究

The study of histidine dipeptide and water clusters using ab initio method and ABEEMσπ model

使用密度泛函B3LYP／6‐311＋＋G（d ，p）方法对组氨酸二肽与水团簇的结构进行优化，在M P2／aug‐cc‐pVDZ水平下计算了这些体系的结合能，同时考虑了基组重叠误差（BSSE）和零点能（ZPE）校正。应用ABEEMσπ浮动电荷分子力场优化了组氨酸二肽与水分子所形成的团簇结构，计算了氢键键长和氢键键角，同时计算了组氨酸二肽与1～6个水分子所形成的团簇His（H2O）n（n＝1～6）的结合能，探讨了氢键的协同效应。将ABEEMσπ浮动电荷分子力场、OPLSAA和AMBER力场所得的结果与从头算方法的结果进行了比较，ABEEMσπ的结果好于OPLS‐AA 和AMBER力场的，可与从头算方法所得到的结果相媲美。

B3LYP/6‐311＋ ＋G （d ,p） level was used to optimize the geometries of the clusters of his‐tidine dipeptide （His） and water His（H2 O）n （n=1~6） .The binding energies of the clusters were calculated by using MP2/aug‐cc‐pVDZ level with basis set superposition error （BSSE） and zero point energy （ZPE） correction .ABEEMσπ fluctuating charge force field was employed to calculate hydro‐gen‐bond lengths and angles .We calculated the binding energies of the His （H2 O）n （n=1~6） ,and explored the cooperative effects of their hydrogen‐bond .The results of ABEEMσπ ,OPLS‐AA ,AM‐BER force field were compared with those of MP2/aug‐cc‐pVDZ ,respectively .Binding energies from ABEEMσπforce field was in good agreement with those of ab initio method .