Relationship between Aggregation of Amyloid-β Protein on Cells and Cytotoxicity

Abstract

Both peptides were a-helical in dry state and gradually transitioned to intramolecular and then to intermolecular b-sheet upon exposure to vapor. The onset of b-sheet formation was delayed in AbpE but proceeded rapidly once triggered. AbpE inhibited the transition of Ab to intermolecular b-sheet structure, while Ab shifted the structure of AbpE towards more b-turn and less intermolecular b-sheet structure. Thus, each peptide inhibits intermolecular b-sheet formation in the other. This may explain the increased toxicity of oligomeric Ab þ AbpE peptide combinations as fibrils are less toxic. Additionally, the rapid formation and retention of b-turn structure in AbpE may facilitate its increased toxicity.