Wolfersberger M G, Chen X J, Dean D H
Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, USA.
Appl Environ Microbiol. 1996 Jan;62(1):279-82. doi: 10.1128/aem.62.1.279-282.1996.
A series of mutant Bacillus thuringiensis CryIAa delta-endotoxin proteins was prepared by replacing the first, second, and last arginine residues of the conserved third-domain sequence, R-521 YRVRIR-527, with other amino acids. The stable mutant proteins were bioassayed against Bombyx mori larvae and found to all be approximately half as active as wild-type CryIAa. The toxins were also tested by means of a light-scattering assay for their ability to increase permeability of larval B. mori midgut brush border membrane vesicles. Three of the mutant toxins were as active as the wild-type toxin in the vesicle permeability assay.
通过将保守的第三结构域序列R-521 YRVRIR-527的第一个、第二个和最后一个精氨酸残基替换为其他氨基酸,制备了一系列苏云金芽孢杆菌CryIAaδ-内毒素突变蛋白。对稳定的突变蛋白进行了针对家蚕幼虫的生物测定,发现它们的活性均约为野生型CryIAa的一半。还通过光散射测定法测试了这些毒素增加家蚕幼虫中肠刷状缘膜囊泡通透性的能力。在囊泡通透性测定中,三种突变毒素与野生型毒素活性相同。