Diabrotica toxins

摘要

New modified Cry proteins, particularly modified CryIIIA proteins, having significantly altered toxicity, and DNA sequences encoding these proteins, are designed. Analysis of solvent-accessible amino acid positions in domain II of the CryIIIA protein by alanine-scanning mutagenesis identified individual amino acids involved in corn rootworm toxicity. Random replacement of these amino acids identifies modified proteins with improved toxicity. A combination of all or most thus identified improved amino acids in a single protein yields modified CryIIIA proteins with significantly improved toxicity. Particularly regions protruding from the Cry molecule and located at the apex of the Cry proteins, were identified as involved in toxicity.