Identification of Key Residues Associated with the Interaction between Plutella xylostella Sigma-Class Glutathione S-Transferase and the Inhibitor S-Hexyl Glutathione

摘要

Glutathione S-transferases (GSTs) are important detoxification enzymes involved in the development of metabolic resistance in Plutella xylostella. Uncovering the interactions between representative PxGSTs and the inhibitor S-hexyl glutathione (GTX), helps in the development of effective PxGST inhibitors for resistance management. As the PxGST most severely inhibited by GTX, PxGST sigma (sigma-class PxGST) adopts the canonical fold of insect GSTs. The formation of the PxGST sigma-GTX complex is mainly driven by H-bond and hydrophobic interactions derived from the side chains of favorable residues. Of the residues composing the active site of PxGST sigma, Lys43 and Arg99 are two hot spots, first reported in the binding of GSH derivatives to GSTs. Such differences indicate the metabolism discrimination of different insect GSTs. Unfavorable interactions between the PxGST sigma active site and GTX are depicted as well. The research guides the discovery and optimization of PxGST sigma inhibitors.