Characterization of Amyloid β Fibrils with An Aqueous Two-Phase System: Implications of Fibril Formation

The pathological process of Alzheimer's disease is closely related to amyloid fibril formation by the causative protein, amyloid β (Aβ). The growth behavior of Aβ fibrils is predominated by the seeds-monomeric Aβ interaction. In this study, the local hydrophobicity of seeds of Aβ fibrils was investigated by the aqueous two-phase partitioning method to evaluate the hydrophobic interaction between the seed-monomeric Aβ. The seeds showed a high local hydrophobicity relative to the monomer and fibrils. From the fibril growth experiment and the additive effect of Triton X-100, we could demonstrate the contribution of the hydrophobic seeds-monomer interaction to fibril formation.