苏云金芽孢杆菌 (Bacillusthuringiensis)杀虫晶体蛋白的毒性片段包含三个不同的结构域。通过对毒性片段编码基因的定点诱变和体外重组 ,已经对结构域的功能有了较清晰的认识。一般认为结构域Ⅰ参与孔道的形成 ,结构域Ⅱ决定毒素与受体的特异性结合 ,结构域Ⅲ主要调节毒素的活性。本文根据国外研究 ,从毒素蛋白质结构的不同组织层次 ,阐述了这些区域的结构与其功能的关系 The toxic fragment of the Bacillus thuringiensis insecticidal crystal protein contains three distinct domains. Through the site-directed mutagenesis and in vitro recombination of the gene encoding the toxic fragment, the function of the domain has been clearer. Domain I is generally believed to be involved in pore formation. Domain II determines the specific binding of toxins to the receptor. Domain III regulates toxin activity. According to the foreign studies, this paper elaborates the relationship between the structure and function of these toxins from different organizational levels of the toxin protein structure