The conformation of Fab, Amyloid peptide 1-40 (Ab1-40) with N-terminal attached fluoresein was investigated as the peptide attached to a nanogold colloid. Various sizes of nanogold colloids were used and the picosecond fluorescence dynamics of fluorescein reflecting the conformation of Ab1-40 were observed. The fluorescence intensity increased when Ab1-40 was adsorbed on a gold colloid, however no significant change in dynamics was found for any given size of nanogold colloid. The lifetime was slowed as the size of the gold colloid was increased, resulting in nanosize dependent dynamics. The enhancement of fluoresence due to the presence of the gold colloids supports that nonradiative channels were closed. Based on these results, it is thought that the Ab1-40 monomers align in an organized way along the conformation of the oligomer while maintaining enough distance between one another, allowing unfavorable interactions to be minimized. A drastic quenching of the fluorescence was observed in both highly acidic and basic conditions. The source of the quenching in highly acidic conditions is due to a network formed between unfolded monomers. Increased contact between the folded monomer and the nanogold colloidal surface is a major source of quenching at highly basic conditions.

Studying amyloid peptide oligomer dynamics over nanometer-interface

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.