Proteolytic processing of Bacillus thuringiensis Cry3Ca toxinby different protease digestion treatments

Abstract: Cylas puncticollis (Coleoptera: Brentidae) is one of the most important biologicalthreats to sweet potato productivity in East Africa. The control of this insect pest is difficult dueto their cryptic feeding behaviour. Recently, the Cry3Ca toxin was found to be toxic to Cylas spp.However, little is known about the mode of action of this Cry toxin active against C. puncticollis.The present work studied the proteolytic activation pattern of the Cry3Ca 70kDa protoxin aftertreatment with commercial enzymes, midgut juice and brush border membrane vesicles(BBMVs). Our results showed that the activated fragment obtained after all treatments is apolypeptide of about 50 kDa.