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Updated: May 11, 2026

Purification and Aggregation of the Amyloid Precursor Protein Intracellular Domain
Published on: August 28, 2012
Nucleation process of a fibril precursor in the C-terminal segment of amyloid-β
Fahimeh Baftizadeh1, Fabio Pietrucci, Xevi Biarnés
1SISSA, via Bonomea 265, I-34136 Trieste, Italy.
Abstract:
By extended atomistic simulations in explicit solvent and bias-exchange metadynamics, we study the aggregation process of 18 chains of the C-terminal segment of amyloid-β, an intrinsically disordered protein involved in Alzheimer's disease and prone to form fibrils. Starting from a disordered aggregate, we are able to observe the formation of an ordered nucleus rich in beta sheets. The rate limiting step in the nucleation pathway involves crossing a barrier of approximately 40 kcal/mol and is associated with the formation of a very specific interdigitation of the side chains belonging to different sheets. This structural pattern is different from the one observed experimentally in a microcrystal of the same system, indicating that the structure of a "nascent" fibril may differ from the one of an "extended" fibril.
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