Structure-Function Analysis of Cysteine-Engineered Entomopathogenic Toxins

The availability of bacterial toxin genes and, in many cases, their atomic structures permits, through properly designed structure-function studies, the precise mapping of the molecular determinants of their activity. The results of such studies are of particular importance for the elucidation of the mode of action of the toxins and the design of genetically engineered molecules displaying novel activity. For example, a large effort is currently underway to design, through mutagenesis and chimeric constructs, the next generation of Bacillus thuringiensis toxin-based pesticides with different specificities, improved toxicity, and the potential to delay pest resistance (1 ).