甜菜夜蛾化学感受蛋白SexiCSP2结合特性和机理研究

The binding specificity and mechanism of chemosensory protein SexiCSP2 in the beet armyworm,Spodoptera exigua

为阐明甜菜夜蛾Spodoptera exigua化学感受蛋白识别外源化合物的特性和作用机制,运用Western blotting法分析SexiCSP2蛋白在成虫各组织的表达谱,荧光竞争结合试验法测定SexiCSP2蛋白与25种外源配基的结合特性,运用分子对接、分子动力学、结合自由能计算等方法研究SexiCSP2与配基的结合模式。结果显示SexiCSP2在成虫接触和非接触性器官中均有表达,与己醛结合能力最强,解离常数为1.3μmol/L;分子模拟结果显示SexiCSP2与己醛结合形成1个氢键,两者结合自由能为-32.94 kJ/mol,主要驱动力为范德华力,主要抑制力为非极性溶剂化能。这些结果说明SexiCSP2在甜菜夜蛾识别外源化合物中起重要作用,可以作为防控甜菜夜蛾的有效靶标。

To determine the binding characteristics and mechanism of Spodoptera exigua chemosensory proteins(CSPs)in discriminating exogenous compounds,the expression profiles of SexiCSP2 in adult tissues were analyzed by Western blotting,the binding specificities of SexiCSP2 and 25 foreign ligands were tested through fluorescence competitive binding assay.Moreover,the binding pattern was studied by using molecular docking,molecular dynamics simulation and binding free energy calculation methods.The results showed that SexiCSP2 was expressed in both contact and non-contact organs.It had a strongest binding ability to hexanal with a dissociation constant of 1.3μmol/L.Molecular simulation results showed that hexanal formed a hydrogen bond with SexiCSP2,and the binding free energy was-32.94 kJ/mol;the van der Wals was the main driving force,and the nonpolar solvation energy was the main resistance force.These data indicated that SexiCSP2 might play an important role in the process of discriminating exogenous compounds and could be used as an effective target for the prevention and control of S.exigua.