The 16-22 amino acid fragment of the beta-amyloid peptide associated with the Alzheimer's disease, Abeta, is capable of forming amyloid fibrils. Here we study the aggregation mechanism of Abeta(16-22) peptides by unbiased thermodynamic simulations at the atomic level for systems of one, three and six Abeta(16-22) peptides. We find that the isolated Abeta(16-22) peptide is mainly a random coil in the sense that both the alpha-helix and beta-strand contents are low, whereas the three- and six-chain systems form aggregated structures with a high beta-sheet content. Furthermore, in agreement with experiments on Abeta(16-22) fibrils, we find that large parallel beta-sheets are unlikely to form. For the six-chain system, the aggregated structures can have many different shapes, but certain particularly stable shapes can be identified.
@article{arxiv.q-bio/0409005,
title = {Oligomerization of amyloid Abeta peptides using hydrogen bonds and hydrophobicity forces},
author = {Giorgio Favrin and Anders Irbäck and Sandipan Mohanty},
journal= {arXiv preprint arXiv:q-bio/0409005},
year = {2009}
}