Shared Binding Sites for the Bacillus thuringiensis Proteins Cry3Bb, Cry3Ca, and Cry7Aa in the African Sweet Potato Pest Cylas puncticollis (Brentidae)

ABSTRACT Bacillus thuringiensis Cry3Bb, Cry3Ca, and Cry7Aa have been reported to be toxic against larvae of the genus Cylas , which are important pests of sweet potato worldwide and particularly in sub-Saharan Africa. However, relatively little is known about the processing and binding interactions of these coleopteran-specific Cry proteins. The aim of the present study was to determine whether Cry3Bb, Cry3Ca, and Cry7Aa proteins have shared binding sites in Cylas puncticollis to orient the pest resistance strategy by genetic transformation. Interestingly, processing of the 129-kDa Cry7Aa protoxin using commercial trypsin or chymotrypsin rendered two fragments of about 70 kDa and 65 kDa. N-…