Issue 24, 2019

Atomic resolution map of the soluble amyloid beta assembly toxic surfaces


Soluble amyloid beta assemblies (Aβn) are neurotoxic and play a central role in the early phases of the pathogenesis cascade leading to Alzheimer's disease. However, the current knowledge about the molecular determinants of Aβn toxicity is at best scant. Here, we comparatively analyze Aβn prepared in the absence or presence of a catechin library that modulates cellular toxicity. By combining solution NMR with dynamic light scattering, fluorescence spectroscopy, electron microscopy, wide-angle X-ray diffraction and cell viability assays, we identify a cluster of unique molecular signatures that distinguish toxic vs. nontoxic Aβ assemblies. These include the exposure of a hydrophobic surface spanning residues 17–28 and the concurrent shielding of the highly charged N-terminus. We show that the combination of these two dichotomous structural transitions promotes the colocalization and insertion of β-sheet rich Aβn into the membrane, compromising membrane integrity. These previously elusive toxic surfaces mapped here provide an unprecedented foundation to establish structure-toxicity relationships of Aβ assemblies.

Graphical abstract: Atomic resolution map of the soluble amyloid beta assembly toxic surfaces

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Article information

Article type
Edge Article
19 Mar 2019
19 May 2019
First published
21 May 2019
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2019,10, 6072-6082

Atomic resolution map of the soluble amyloid beta assembly toxic surfaces

R. Ahmed, M. Akcan, A. Khondker, M. C. Rheinstädter, J. C. Bozelli, R. M. Epand, V. Huynh, R. G. Wylie, S. Boulton, J. Huang, C. P. Verschoor and G. Melacini, Chem. Sci., 2019, 10, 6072 DOI: 10.1039/C9SC01331H

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