Figure 1.

Overview of the scientific approach. Level 1 is focused on (A) the preparation of Aβ rings starting from an initial NMR conformation of Aβ, which lead to (B) the generation of 1000 different conformers of Aβ. (C) These conformers were clustered into 77 groups, and (D) the best centroid conformer was selected from each cluster as a representative structure. (E) Centroid monomers were docked to form dimers, and (F) the dimers with the best energy were selected. (G) Consistent docking of the conformers to the dimers was conducted. It resulted in generation of rings, fibrils, or nonpropagating dimers. Level 2 is focused on the analysis of ring structures. (H) Rings were evaluated for membranephilicity and (I) selected for further analysis. (J) Dimers from the rings with the best energy of interaction with the membrane were examined after which (K) the interpeptide contacts were studied to determine key amino acid residues. Level 3 is focused on the biological effects of mutating key aa residues. The wild type (WT) and two mutant peptides (L) were evaluated for peptide aggregation using Western blot (M), for ring and fibril formation in a cell-free environment using transmitted electron microscopy (N), and for cytotoxicity in primary neuronal cultures (O).