Insilico Structural 3D Modelling of Novel Cry1Ib9 and Cry3A Toxins from Local Isolates of Bacillus thuringiensis

Abstract

Three-dimensional (3D) models for the 79.2 kDa activated Cry1Ib9 and 77.4 kDa activated Cry3A d-endotoxins from Bacillus thuringiensis (Bt) native isolates that are specifically toxic to Coleopteran insect pests were constructed by utilizing homology modeling online tool. Evidences presented here, based on the identification of structural equivalent residues of Cry1Ib9 and Cry3A toxin through homology modelling indicate that, they share a common Bt toxin tridimensional structure. The main differences observed in Cry1I9 domain I at positions a2b (S56-I60), a4 (F78-l93) and additionally b0 (Q10-L12), a8a (T280-V282) were observed, in domain II at positions a9b (P333-L339), b6(T390-Q393), b7(V398-W404), b8 (V418-W425), b9 (E453-N454), b10 (S470-I479) where as in domain III the changes were observed at positions b19 (R601-F607), b20 (609-L613), b21 (S618-F627) and a11a (K655-F664), a13, a14 components present at downstream sites, where as in Cry3A main differences observed in domain I is at the position of a4 (P105-I152), a5 (Q163-A185), b1A(E190-L192), a6 (F193-Y217), Domain II is not consevered and main variations were observed at b2 (E292-L295), b3

Draft genome sequence of Bacillus thuringiensis strain S2195, an isolate toxic for lepidoptera / Projeto de sequência do genoma de Bacillus thuringiensis strain S2195, um tóxico isolado para lepidoptera

“…Bacillus thuringiensis is a Gram-positive bacterium that occurs naturally in many environments including soil. The distribution of this bacterium is worlwide (1). Bacillus thuringiensis (Bt) produces insecticidal proteins classified into two families of membrane perforating toxins, crystalline (Cry) and cytolytic (Cyt) proteins.…”