A Novel Sea Anemone Peptide Ed-79 Blocks Shaker Kv Channels and Exhibits Insecticidal Activity

The escalating resistance of agricultural pests to conventional chemical insecticides has created an urgent need for eco-friendly biological alternatives with novel modes of action. Sea anemone venoms are rich in structurally stable and target-specific ion channel-modulating peptides, representing a promising source of new insecticidal molecules. Through bioinformatics screening of the transcriptome database of the sea anemone Exaiptasia diaphana, we identified a novel 37-residue peptide, Ed-79, which contains three disulfide bonds. The peptide was chemically synthesized via solid-phase peptide synthesis (SPPS) and successfully folded into its correct disulfide-bonded form using a three-step oxidative folding strategy, as confirmed by LC-MS and RP-HPLC. Circular dichroism (CD) spectroscopy revealed marked secondary-structural changes upon oxidative folding, notably an increased β-sheet content. In insecticidal bioassays, Ed-79 exhibited dose-dependent lethality against Spodoptera frugiperda and Tenebrio molitor, with LD50 values of 289.5 and 367.2 pmol/g, respectively. Molecular docking further predicted that Ed-79 binds stably to the outer vestibule of the Shaker Kv channel pore via eight hydrogen bonds, with Pro475 and Asn482 potentially serving as key interacting residues. Collectively, this is the first systematic report on the synthesis, oxidative folding, insecticidal activity, and predicted Shaker Kv channel-binding mode of Ed-79, providing a solid foundation for developing new insecticidal lead compounds and broadening the utility of anemone venoms as insecticide resources.