Protein Engineering Of Bt Genes cry1Ab And cry1Ba For The Development Of Chimeric Genes cryAbabba, cryBabaab And cryAbbaab Via Domain Swapping

Abstract

Bacillus thuringiensis is renowned for its production of insecticidal cry proteins, widely utilized in crop protection to combat insects. However, the risk of insect resistance emerges due to the relatively loose binding of toxins to target sites on larvae's midgut brush boundary membranes. This resistance primarily stems from modifications in binding sites within midgut cells. To address potential threats, the discovery of new Cry proteins is imperative as insects continually evolve resistance against existing ones. Combining Cry toxins with diverse binding sites in larval midguts is proposed as an effective strategy to delay the onset of resistance. In this study, three chimeric B. thuringiensis proteins—CryAbAbBa, CryBaBaAb, and CryAbBaAb—were engineered via domain swapping, utilizing crystal proteins CrylAb and CrylB. Structural validation was conducted, confirming their integrity through Ramachandran Plots. The chimeric proteins can be used as additional resources in crop improvement programmes.