【摘要】 采用分子对接方法研究了杀线虫苏云金芽胞杆菌晶体蛋白Cry5Aa与线虫糖脂受体寡糖片段的互作模式。结果表明:Cry5Aa与寡糖片段的结合位点在晶体蛋白结构域Ⅰ和结构域Ⅱ之间。Cry5Aa与寡糖片段的之间作用能主要为构象能,其次为氢键能,而静电作用能为零。二者之间能够形成10个氢键和多个构象能作用。其中晶体蛋白Cry5Aa结构域Ⅰ氨基酸残基T298可与寡糖片段形成3个氢键,并且该氨基酸残基同样对构象能的贡献较大。Cry5Aa与寡糖片段的之间可以形成稳定的复合物。本研究结果对了解苏云金芽胞杆菌晶体蛋白Cry5Aa的毒理机制和开展定点突变提高Cry5Aa杀线虫活性具有指导意义。更多还原

【Abstract】 Molecular docking was used to simulate the interaction between nematicidal Bacillus thuringiensis crystal protein CrySAa and its oligosaccharides fragment of the glycolipid receptor of target nematode.Results showed that the receptor binding site was located between domain I and domain II of Cry5 Aa.The main interaction energy was the steric energy,next was the hydrogen bonding energy and the electrostatic interaction energy zero.Ten hydrogen bonds and several steric interactions were found in the binding site.Three hydrogen bonds were related to Thr298 in domain I that also contributed much to the steric energy.And as a result CrySAa and its receptor oligosaccharides formed a stable complex.The available results in this paper may help in understanding the action mode of CrySAa and designing mutagenesis experiments aimed to the improvement of nematicidal toxicity.更多还原