石杉碱甲与乙酰胆碱酯酶作用的分子模拟研究

Molecular Modeling Studies of Interactions between Huperzine A and Acetylcholinesterase

目的阐明石杉碱甲与乙酰胆碱酯酶结合的分子机制和关键氨基酸。方法运用分子对接和分子动力学方法分析石杉碱甲与乙酰胆碱酯酶的结合位点;MM-PBSA方法计算两者的结合自由能和作用力的类型、大小;丙氨酸突变扫描方法评估关键残基对结合自由能的贡献。结果复合物中石杉碱甲与Glu202形成1个氢键,与Trp86和Tyr337形成π-π堆积作用;结合自由能为-18.18kcal·mol^(-1),范德华力和静电作用力为主要驱动力,非极性溶剂化能是主要抑制作用力;丙氨酸突变扫描结果显示残基Hid442的ΔΔG_(bind)为3.17kcal·mol^(-1)。结论氢键和π-π堆积作用是石杉碱甲活性的分子基础,残基Hid442在石杉碱甲与乙酰胆碱酯酶的结合中起重要作用。

Objective To clarify the molecular mechanism and key amino acids of huperzine A with acetylcholinesterase.Methods Binding sites of huperzine A with acetylcholinesterase were investigated using AutoDock molecular docking and molecular dynamics and the binding free energy.The type and size of the driving force were counted with MM-PBSA method,Moreover,the contribution of key residues to binding free energy was evaluated using alanine scanning mutagenesis（ASM）.Results In the complex,huperzine A combined with Glu202 to form a hydrogen bond and form π-πstacking interactions with Trp86 and Tyr337.The binding free energy was-18.18 kcal·mol^-1,the van der Waals force and electrostatic were the main driving force and the nonpolar solvation energy was the main resistance force of the binding.TheΔΔG（bind） was 3.17 kcal·mol^-1 by ASM.Conclusion Hydrogen bond andπ-πstacking interactions are the molecular basis of huperzine A activity,and the residue Hid442 plays an important role in the combination of huperzine A with acetylcholinesterase.