Buzdin A A, Revina L P, Kostina L I, Zalunin I A, Chestukhina G G
Institute of Genetics and Selection of Industrial Microorganisms, Moscow, 113545, Russia.
Biochemistry (Mosc). 2002 May;67(5):540-6. doi: 10.1023/a:1015594127636.
A protein with the molecular weight of 65 kD is the only component of Aedes aegypti larvae BBM capable to specifically bind mosquitocidal toxins Cry4B and Cry11A of Bacillus thuringiensis. This protein lacks the leucine aminopeptidase activity which is characteristic for the toxin-binding proteins from the membranes of caterpillars. Cry-toxins inactive against A. aegypti larvae either fail to bind to the 65-kD protein and to a putative product of its proteolysis with the molecular weight of 62 kD (Cry1Ab), or bind but do not compete for this binding with mosquitocidal proteins (Cry9A). The proteolytic splitting out of the first five alpha-helices in the Cry4B toxin molecule does not affect its binding to the 65- and 62-kD proteins, but an additional removal of 20-30 amino acids from the C-terminal of the molecule sharply spoils this binding. Monosaccharide residues are not involved in the binding of the 65- and 62-kD proteins with Cry4B, Cry11A, and Cry9A.
一种分子量为65 kD的蛋白质是埃及伊蚊幼虫刷状缘膜泡（BBM）中唯一能够特异性结合苏云金芽孢杆菌杀蚊毒素Cry4B和Cry11A的成分。这种蛋白质缺乏亮氨酸氨肽酶活性，而这种活性是毛虫细胞膜中毒素结合蛋白的特征。对埃及伊蚊幼虫无活性的Cry毒素要么无法与65-kD蛋白质及其分子量为62 kD的蛋白水解假定产物（Cry1Ab）结合，要么能结合但不能与杀蚊蛋白（Cry9A）竞争这种结合。Cry4B毒素分子中前五个α-螺旋的蛋白水解裂解不影响其与65-kD和62-kD蛋白质的结合，但从分子C端额外去除20 - 30个氨基酸会严重破坏这种结合。单糖残基不参与65-kD和62-kD蛋白质与Cry4B、Cry11A和Cry9A的结合。
