Figure 2.

Amyloid formation kinetics for 40 μM Aβ42 in 20 mM sodium phosphate buffer (pH 7.4) with 25 mM NaCl or NaF, respectively, were tracked for six incubation time points with different techniques. (A) Time-dependent fraction of different s-value species determined by SV analyses. Each data point represents the fraction of the specific s-value species of the total amount of Aβ42 at a certain time point of incubation. The integrated signal from c(s) distributions for a specific s-value range, transformed into percentage of total concentration, was used to calculate the fractions for monomers (0–1 S), oligomers (1–20 S), and large aggregates (>280 S) (from yellow to red). Data points represent mean values with standard deviations from triplicate measurements. Error bars may be hidden by dots. (B) ThT fluorescence measurements for triplicate samples over time representing amyloid fibril mass evolution; data (white dots) are fitted with Eq. 2 from (31) (black line). Error bars may be hidden by dots. (C) CD measurements over time. Mean residue ellipticity at 216 (light gray dots) and 198 nm (dark gray dots) with separate y axes. (D) Weight averaged s-values from peak integration for monomer and three classes of oligomers over time determined in triplicate (from light to dark blue). Error bars may be hidden by dots. (E) c(s) distributions in triplicate for different incubation times. The magnification visualizes oligomeric species from 1 to 19 S. The c(s) distributions were normalized to one, according to the area under the curve for the complete s-value range from 0 to maximum s-value and potential material loss, due to large aggregates sedimenting during acceleration was taken into account. Different colors indicate different incubation times. To see this figure in color, go online.