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

CLC Number: 

• S865.49