Figure 3

SANS analysis of Meta-αS-Os. (a) Kinetics of amyloid fibril formation of αS (5 mg/ml) in 5 mM Mes (at pH 6.5) containing either D₂O (closed circles) or H₂O (open circles). Aliquots of the aggregates were collected at four different time points of (i) 0.25 hr, (ii) 3 hr, (iii) 4 hr, and (iv) 15 hr. (b) TEM images of (i) oligomers, (ii) associated oligomers, (iii) short fibrils, and (iv) mature fibrils. (c) SANS intensities of the αS aggregates obtained at different incubation time points of 0.25 hr (cyan), 0.5 hr (black), 1 hr (gray), 3 hr (green), 4 hr (red), 5 hr (violet), 7 hr (pink), and 15 hr (blue). SANS intensities are vertically shifted to clearly show the differences in their SANS patterns. (d) SANS spectra of Meta-αS-Os at the protein concentration of either 2.5 (open dots) or 5.0 (closed dots) mg/ml. The red solid lines are the theoretical fits to the polydisperse Gaussian Coil (pGC) model. (e) Structure of Meta-αS-O schematized based on the SANS analysis. The diameter of 100 Å is indicated. (f) Schematic representation of the Meta-αS-O structures obtained at different temperatures of 37 °C, 39 °C, 41 °C, and 43 °C, with diameters of 106.1 Å, 98.6 Å, 95.9 Å, and 94.7 Å, respectively. (g) Plot of temperature-dependent decline percentage of the diameters.