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. 2012 May 29;10(5):e1001335. doi: 10.1371/journal.pbio.1001335

Figure 3. Nanomechanical analysis of Aβ42.

Figure 3

ΔL c (left) and F (right) histograms of pFS-2 polyproteins carrying Aβ42. The wt protein (first row) shows broad polymorphism ranging from NM conformers (orange bars) to M conformers (red bars). No hM conformers were found in this protein. Incubation of Aβ42 with and without SV111 (100 µM [38]) yielded similar results, strongly indicating that our SMFS data reflect unfolding events originating from different conformations adopted by the monomeric forms of NPs (as opposed to intermolecular interactions of the oligomeric species). Arc Aβ42 (E22G) familial-disease mutation increases the number of M and hM conformers when compared to the wt protein. Incubation with QBP1 peptide (20 µM [42]) does not impair the formation of M conformers in Arc Aβ42. For F19S/L34P Aβ42 only NM conformations were observed despite the larger sample size (Table 1). TEM images of the amyloid fibers formed by the corresponding proteins are shown on the right. From bottom to top, the scale bars correspond to 0.6, 0.6, 0.45, 0.35, and 0.9 µm, respectively. An example of hM conformer of Arc Aβ42 is shown in the inset.