Probing the Amyloid Peptide-Membrane Interaction Using a Liposome Model System

The aggregation of amyloid peptides is closely related to the pathogenesisof degenerative diseases. More and more evidence implies that the protofibrillar intermediates rather than the mature amyloid fibrils are the toxicspecies related to the membrane disruption. In this work we found that theself-assembling intermediates of Aβ33-42 during early aggregation are ableto break down the liposome. During the process of amyloid peptide (Aβ33-42)intermediate binding to liposome, the β-sheet secondary structure of peptidetook change on the molecular level which was characterized by circulardichroism (CD) spectra. The small micelles were formed due to the disruptionof amyloid peptide, and further to grow into big irregular complexes withfurther incubation, which is characterized by the assay of disrupting liposomemembrane and atomic force microscopy (AFM). This founding paved the wayto understand the interactions between the amyloid peptide and membranes,and support the amyloid peptide nanostructure formed in the early stage ofaggregation has good affinity with membrane.