Resistance Mechanism of (L.) Associated with Amino Acid Substitutions in Acetylcholinesterase-1: Insights from Homology Modeling, Docking and Molecular Dynamic Simulation.

a destructive crucifer pest, can rapidly develop resistance to most classes of pesticides. This study investigated the molecular resistance mechanisms to chlorpyrifos, an organophosphate pesticide. Two genes, and , were described. The nucleotide sequence results revealed no variation in while the resistant strain (Kar-R) had four amino acid alterations in , two of which (A298S and G324A) were previously shown to confer organophosphate resistance in In the present study, the 3D model structures of both the wild-type (Gu-S) and mutant (Kar-R) of strains were studied through molecular dynamics (MDs) simulations and molecular docking. Molecular dynamics simulations of RMSD revealed less structural deviation in the mutant than in its wild-type counterpart. Higher flexibility in the 425-440 amino acid region in the mutant active site (Glu422 and Acyl pocket) increased the active site's entropy, reducing the enzyme's affinity for the inhibitors. Gene expression analysis revealed that the relative transcription levels of were significantly different in the Kar-R strain compared with the Gu-S strain. This study enhances the understanding of the mechanisms governing 's resistance to insecticide and provides essential insights for new insecticides as well as valuable insights into environmentally conscious pest management techniques.