Ac-LVFFARK-NH conjugation to β-cyclodextrin exhibits significantly enhanced performance on inhibiting amyloid β-protein fibrillogenesis and cytotoxicity.

Inhibition of amyloid β-protein (Aβ) aggregation is of significance for the potential treatment of Alzheimer's disease. We have herein conjugated heptapeptide Ac-LVFFARK-NH (LK7) to β-cyclodextrin (βCyD) and studied the inhibitory effect of the LK7-βCyD conjugate on Aβ aggregation. The conjugation significantly improved the peptide solubility and suppressed the self-assembly propensity. This led to 30% increase of the binding affinity of LK7 for Aβ in the conjugate due to increased hydrophobic interactions. Thus, LK7-βCyD suppressed the conformational transition of Aβ and showed stronger inhibitory effect on Aβ fibrillation than LK7. Thus, LK7-βCyD exhibited protective effect on Aβ-induced cytotoxicity, and the cells completely survived at 10 molar excess of LK7-βCyD (from 67% to 100%). By contrast, LK7 showed only a moderate inhibition on Aβ fibrillation, and could not inhibit the amyloid cytotoxicity. The research proved that conjugation of hydrophobic peptide to βCyD was promising to increase its inhibition potency against Aβ aggregation.