β-Roll-targeting peptide and Ectoine synergy: A novel strategy to impair dengue NS1 function.

Non-structural protein 1 (NS1) of the dengue virus (DENV) is essential for viral replication and immune evasion, primarily functioning as a dimer or hexamer. The β-roll domain plays a crucial role in NS1 dimerization, making it a promising target for therapeutic intervention. This study investigates the potential of a synthetic peptide derived from the β-roll domain to disrupt NS1 dimerization and function. Using surface plasmon resonance (SPR), circular dichroism (CD) spectroscopy, enzyme-linked immunosorbent assay (ELISA), and molecular dynamics (MD) simulations, we demonstrate that the peptide binds strongly to NS1, destabilizing its secondary structure and impairing its biological function. SPR analysis revealed a dissociation constant (KD) of 0.12 μM and a Gibbs free energy change (∆G) of -9.44 kcal/mol, indicating high binding affinity and thermodynamic favorability. CD spectroscopy confirmed a significant reduction in β-sheet content, with a corresponding increase in disordered structures, suggesting peptide-induced destabilization of NS1. ELISA results further showed a concentration-dependent loss of NS1 recognition by specific antibodies, indicating functional impairment. Notably, ectoine, a natural osmolyte, enhanced peptide stability and interaction strength, further exacerbating NS1 disruption. These findings highlight the potential of β-roll-targeting peptides as novel inhibitors of NS1 function and propose ectoine as an effective stabilizing co-solvent to improve peptide efficacy. This study provides a strong foundation for developing peptide-based therapeutics against dengue virus infections.