Aβ₄₂ oligomers can seed the fibrillization of Aβ₄₀ peptides

Aggregation of Aβ₄₀ and Aβ₄₂ are considered as pivotal players in the pathogenic mechanism of Alzheimer's disease. In this work, we applied reverse micelles formed by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) to prepare oligomeric aggregates of Aβ₄₀ or Aβ₄₂ peptides. The resultant globular aggregates were approximately 22 nm in diameter and they were capable to form mature fibrils upon self-aggregation. Furthermore, we found that the Aβ₄₂ oligomeric aggregates can seed the fibrillization of Aβ₄₀ monomers. Solid-state NMR results revealed that the Aβ₄₀ fibrils seeded by Aβ₄₀ or Aβ₄₂ oligomers adopt a similar molecular structure for the residues near the C-terminus.