Site-directed mutations in the third domain of Bacillus thuringiensis delta-endotoxin CryIAa affect its ability to increase the permeability of Bombyx mori midgut brush border membrane vesicles.
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.
Wolfersberger
M G
MG
Department of Biology, Temple University, Philadelphia, Pennsylvania 19122, USA.
Chen
X J
XJ
Dean
D H
DH
D000818:Animals; D001120:Arginine / Q000502:physiology; D001413:Bacillus thuringiensis / Q000235:genetics / Q000472:pathogenicity*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology* / Q000633:toxicity; D001427:Bacterial Toxins; D012831:Bombyx / Q000502:physiology*; D002463:Cell Membrane Permeability; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology* / Q000633:toxicity; D006460:Hemolysin Proteins; D007814:Larva; D008871:Microvilli / Q000502:physiology; D016297:Mutagenesis, Site-Directed; D009154:Mutation
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D001120:Arginine