摘要： 利用SWISS-MODEL服务器对BmK IT毒素进行三维结构同源建模,结果表明,BmK IT三维构象与BmK IT-AP、Bj-xtr IT、BmKβIT在二级结构的排列顺序和空间结构上相似,并且这四者的C末端对于蝎昆虫神经毒素特异作用于昆虫钠离子通道至关重要。根据表面静电势分析,推断在果蝇的钠通道D2区的一个额外涉及兴奋性蝎抗昆虫毒素对该通道的选择性识别的区域应呈现正电势。接着,采用Hampton Research公司的晶体生长试剂盒中的50个缓冲液配方筛选BmK IT的结晶条件,在温度为28℃,缓冲液配方为0.1 mol/L磷酸二氢钾、0.1 mol/L一水合磷酸二氢钠、0.1 mol/L一水合吗啉乙磺酸、2.0 mol/L氯化钠(pH6.5),时间为6个月时生长出五边形晶体。研究结果将为从分子水平上揭示其结构与抗农业虫害的功能关系奠定基础。

关键词: 东亚钳蝎昆虫毒素, 结构建模, 表面静电势, 结晶

Abstract: The insect excitatory neurotoxin(BmK IT)from the scorpion Buthus martensii Karsch is selectively ac. tive on the lepidopterous and dipterous insects.Prediction of three dimensional structure of BmK IT was performed by SWISS-MODEL workspace.The 3-D structure of BmK IT was similar to BmK IT-AP, Bj—xtr IT and BmK BIT.The Cterminal of these toxins was important to active selectively on the sodium channel of insect ceils.The calculated elec— trostatic potential surface around the C·terminal of BmK IT suggested that the section of domain 2 in voltage..gated SO—· dium channel of drosophila, which Was identified by insect toxin, was mainly positive.Crystallization of BmK IT was performed using the hanging-drop method.50 conditions(Crystal Screening Kit, Hampton Research)were used to get crystals.The results showed that pentagonal crystal could be obtained from a condition containing 0.1 mol/L sodium phosphate monobasic monohydrate, 0.1 mol/L potassium phosphate monobasic, 0.1 mol/L MES monohydrate (pH 6.5)and 2.0 mol/L sodium chloride, at 28。C and the protein was dissolved in ddH20.This work could accelerate the research about the relationship between the structure and anti—insect function of BmK IT.

Key words: BmK IT, Prediction of three dimensional structures, Electrostatic potential surface, Crystallization

中图分类号: 

• S865.49