Molecular Microbiology (1999) 31, 463-471

Ruud A. de Maagd, Petra L. Bakker, Luke Masson, Michael J. Adang, Sreedhara Sangadala, Willem Stiekema and Dirk Bosch (1999)
Domain III of the Bacillus thuringiensis delta-endotoxin Cry1Ac is involved in binding to Manduca sexta brush border membranes and to its purified aminopeptidase N
Molecular Microbiology 31 (2), 463-471
Abstract: Three types of binding assays were used to study the binding of Bacillus thuringiensis delta-endotoxin Cry1Ac to brush border membrane vesicle (BBMV) membranes and a purified putative receptor of the target insect Manduca sexta. Using hybrid proteins consisting of Cry1Ac and the related Cry1C protein, it was shown that domain III of Cry1Ac is involved in specificity of binding as observed by all three techniques. In ligand blotting experiments using SDS-PAGE-separated BBMV proteins as well as the purified putative receptor aminopeptidase N (APN), the presence of domain III of Cry1Ac in a hybrid with Cry1C was necessary and sufficient for specific binding to APN. Using the surface plasmon resonance (SPR) technique with immobilized APN, it was shown that the presence of domain III of Cry1Ac in a hybrid is sufficient for binding to one of the two previously identified Cry1Ac binding sites, whereas the second site requires the full Cry1Ac toxin for binding. In addition, the role of domain III in the very specific inhibition of Cry1Ac binding by the amino sugar N-acetylgalactosamine (GalNAc) was determined. Both in ligand blotting and in surface plasmon resonance experiments, as well as in binding assays using intact BBMVs, it was shown that the presence of domain III of Cry1Ac in a toxin molecule is sufficient for the inhibition of binding by GalNAc. These and other results strongly suggest that domain III of delta-endotoxins play a role in insect specificity through their involvement in specific binding to insect gut epithelial receptors.
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Link to article at publishers website
Database assignments for author(s): Ruud A. de Maagd, Michael J. Adang, Luke Masson

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Manduca sexta
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Manduca sexta