蜜蜂与桃蚜烟碱乙酰胆碱受体同源模建与对接

Homology modeling of honeybee and peach-potato aphid nAChRs and surflex-docking

为了探究使用吡虫啉对蜜蜂造成伤害的成因,以"静水椎实螺"的烟碱乙酰结合蛋白与吡虫啉的共晶化合物作为模板,使用分子模拟技术得到蜜蜂和桃蚜烟碱乙酰胆碱受体.通过拉氏图和分子动力学模拟等实验方法验证了受体的可靠性和合理性.将新烟碱类化合物吡虫啉分别与模建受体对接,所得到的结合自由能和对接位点与生物学实验数据和位点突变结果相吻合.吡虫啉分别与蜜蜂、桃蚜烟碱乙酰胆碱受体分子对接结果显示,吡虫啉与蜜蜂、桃蚜烟碱乙酰胆碱受体对接的结合自由能最高值分别为-9.592 4千卡/摩尔和-7.124 1千卡/摩尔,说明该药物对蜜蜂、桃蚜具有同等效力的毒性.吡虫啉的硝基部分在对接中起到了关键作用,在蜜蜂受体中其与阿尔法亚基发生相互作用,而在桃蚜受体中主要与贝塔亚基结合.证明了吡虫啉的使用确实危害到了蜜蜂群体的生存.

To explore how Imidacloprid affect honeybee,three-dimensional models of honeybee（Apis mellifera） α1/β1 and peach-potato aphid（Myzus persicae） α2/β1 nAChRs were constructed using homology modeling method of SYBYL X-1.2,crystal structure of the acetylcholine-binding protein of Lymnaea stagnalis were used as the template.The quality of the models was confirmed by molecular dynamics.Furthermore,nAChR agonist insecticide Imidacloprid（IMI） was docked into the putative binding site of the honeybee（Apis mellifera） α1/β1 and peach-potato aphid（Myzus persicae） α2/β1 nAChRs by Surflex-docking,respectively.The binding free energy of docking results are in agreement with the experimental data and the binding sites were consistent with the results from the labeling and mutagenesis experiments.The binding results of IMI binding with honeybee（Apis mellifera） and peach-potato aphid（Myzus persicae） nAChRs show that the binding free energy of IMI docking with honeybee and peach-potato aphid nAChRs are-9.592 4 kcal/mol and-7.124 1 kcal/mol,respectively,which demonstrates that IMI has the same-level toxicity to honeybee versus peach-potato aphid.Nitro moiety of IMI interacts with α subunit from honeybee nAChR and bind to residues from β subunit from peach-potato aphid nAChR,which plays a key role in the binding interaction.The experiment data prove that using IMI causes harm to the honeybee colony.