ABEEMσπ-GB／SA方法计算6种氨基酸四肽溶剂化自由能

使用ABEEMσπ浮动电荷极化分子力场，在298 K ，NVT 系综下对5种构象的A la四肽水溶液进行了动力学模拟。计算了动力学平衡态下A la四肽中非氢原子的均方根偏差。结合广义玻恩模型（GB）计算了溶剂化自由能的极性部分，使用SA 方法计算了溶剂化自由能的非极性部分。溶剂化自由能的结果表明，A la四肽αR螺旋和β折叠构象容易在水溶液中存在。使用类似方法分别对Gly ，Leu ，Val ，Asn和Asp四肽的αL螺旋构象水溶液进行了动力学研究，计算了这5种四肽的溶剂化自由能。结果表明，A sp和A sn四肽亲水性较强，Leu、Val和Ala四肽疏水性较强，Gly 四肽居中，此结论与实际相符。该类研究为ABEEMσπ浮动电荷力场用于其他生物大分子体系奠定了很好的基础。

Estimation of the salvation free energies of six amino acid tetrapeptides by ABEEM/MM-GB/SA

In this paper ,ABEEMσπfluctuating charge force field was used in the dynamic simulation of five conformations of in aqueous solution at 298 K ,NVT ensemble .The root-mean-square deviations of non-hydrogen atoms in Ala tetrapeptide have been calculated .ABEEMσπcombined with GB was used to calculate the polar part of solvation free energies （SEF） .SA was employed to calculate the non polar part of SFEs .The results of SFEs show that αR and β-sheet conformations of Ala tetrapep-tide in aqueous solution are more stable than other conformations .The dynamic simulations of the αL conformation of Gly ,Leu ,Val ,Asn and Asp tetrapeptides have been investigated in the similar way . ABEEMσπ-GB/SA was employed to calculate their SFEs .It can be obtained that the order of the hy-drophilicity of the six tetrapeptides with αL conformation are Asp 〉 Asn〉 Gly 〉 Val〉 Leu〉 Ala . These results are in agreement with the experiments .It lays a good foundation to make this force field expand the application to other macromolecule systems .