Homology modelling deduced 3-D structure of Bacillus thuringiensis Cry1Ab17 toxin

We predict the first theoretical structural model of the newly reported Cry1Ab17 delta-endotoxin produced by Bacillus thuringiensis using homology modelling. Both Cry1Ab17 and Cry1Aa share a common structure; both contain three flexible domains that participate in the formation of a pore and determine the receptor binding specificity. The main differences between the two is in the length of loops, and in Cry1Ab17, the absence of alpha 7b, alpha 10a, alpha 10b, alpha 12a, beta 19, beta 20 and presence of additional beta 0 beta 1b, alpha 9b components. A few of the components such as alpha 8a, alpha 8b, alpha 9a, alpha 9b, and alpha 11a differ in their locations. A better understanding of the 3-D structure of Cry1Ab17 will be helpful in designing the domain swapping experiments to improve its insecticidal toxicity.