BIOCHEMICAL-CHARACTERIZATION OF THE 3RD DOMAIN FROM BACILLUS-THURINGIENSIS CRY1A TOXINS

Cry proteins from Bacillus thuringiensis have insecticidal properties. The function of domains I and II has been described but domain III ha s so far eluded understanding. Domain III from Cry1Ab and Cry1Ac has b een cloned, expressed in E. coli and injected to rabbits with the aid of characterizing them immunologically. Interestingly, polyclonal anti bodies against Cry1Ab fragment did not recognize either the native Cry 1Ab toxin or the Cry1Ac fragment while those against the latter did re cognize either the native Cry1Ac toxin or the Cry1Ab protein fragment. A combination of information from sequence comparison and hydrophobic ity profile indicates that these protein fragments possibly adopt diff erent spatial dispositions within the respective toxins.