How fullerenes inhibit the amyloid fibril formation of hen lysozyme

Abstract

The inhibition of protein unfolding and self-assembly into fibrils using nanoparticles is a potential medicinal strategy to impede amyloid-related diseases. Among various nanoparticles, fullerenes have attracted great interest because of their inhibition effect on protein fibrillization, but the mechanism of the inhibition process is not properly understood. To explore the inhibition mechanisms, molecular dynamics simulations of hen egg white lysozyme (HEWL), a model of an amyloid-prone protein, have been performed in the presence of varied C60 concentrations. It is found that the structural fluctuation of HEWL decreases as the concentration of C60 increases. As the concentration of C60 increases, clustered fullerene aggregates are formed via hydrophobic interaction rather than interacting with HEWL, and HEWL was adsorbed on the surface of the fullerene aggregates. The maintenance of the structure and the inhibition of HEWL fibrillization by C60 is also experimentally confirmed by thioflavin T fluorescence assays and atomic force microscopy. Thus, two independent methods confirmed that C60 is able to inhibit the formation of amyloid fibrils in a dose-dependent manner. This study is an initial step in understanding by which mechanism C60 inhibits HEWL fibrillization, allowing to further design strategies for amyloid inhibition based on fullerenes and other nanoparticles.