In silico identification of potential phytochemical inhibitors targeting farnesyl diphosphate synthase of cotton bollworm (Helicoverpa armigera)

Helicoverpa armigera (Ha), a polyphagous pest, causes significant damage to several crop plants, including cotton. The control of this cosmopolitan pest is largely challenging due to the development of resistance to existing management practices. The Juvenile Hormone (JH) plays a pivotal role in the life cycle of insects by regulating their morphogenetic and gonadotropic development. Hence, enzymes involved in JH biosynthesis are an attractive target for the development of selective insecticides. Farnesyl diphosphate synthase (FPPS), a member protein of (E)-prenyl-transferases, is one of the most crucial enzymes in the biosynthetic pathway of JHs. It catalyzes the condensation of isopentenyl diphosphate (IPP) with dimethylallyl diphosphate (DMAPP), forming farnesyl diphosphate (FPP), a precursor of JH. The study was designed to identify an effective small inhibitory molecule that could inhibit the activity of Helicoverpa armigera – FPPS (HaFPPS) for an effective pest control intervention. Therefore, a 3D model of FPPS protein was generated using homology modeling. The FooDB database library of small molecules was selected for virtual screening, following which binding affinities were evaluated using docking studies. Three top-scored molecules were analyzed for various pharmacophore properties. Further, molecular dynamics (MD) simulation analysis showed that the identified molecules (mitraphylline-ZINC1607834, chlorogenic acid-ZINC2138728 and llagate-ZINC3872446) had a reasonably acceptable binding affinity for HaFPPS and resulted in the formation of a stable HaFPPS-inhibitor(s) complex. The identified phytochemical molecules may be used as potent inhibitors of HaFPPS thus, paving the way for further developing environment-friendly insect growth regulator(s). Communicated by Ramaswamy H. Sarma