Structure-Guided Design of Temporin-Derived Peptides Reveals Potent Dual-Mechanism Inhibitors of SARS-CoV-2

The study investigates temporin-derived antimicrobial peptides as broad-spectrum antiviral candidates against SARS-CoV-2. Surface plasmon resonance screening shows that temporin G (TG), temporin L (TL), and the nonhemolytic analog Pro 3 -TL bind the trimeric Spike protein with high affinity, following a two-state binding model. NMR confirms TG-Spike interactions and identifies Phe2 as critical for binding. Docking simulations place the interaction at the NTD-RBD interface and reveal a cation-pi interaction between TG Phe2 and Spike Arg357. These insights informed the design of the chimeric analog RB-142 and four derivatives (RB-143 to RB-146) incorporating bulkier aromatic residues. All analogs exhibit submicromolar binding affinities. Biological assays show low cytotoxicity and potent virucidal activity, with RB-146 demonstrating the strongest effect and a high therapeutic index. Mechanistic analyses indicate that RB-146 disrupts viral attachment and damages the viral envelope. The findings position RB-146 as a promising dual-mechanism antiviral candidate.