FIGURE 1.

Time courses of PrP^a and PrP^b fibril formation monitored by ThT fluorescence. PrP (22 μm) was incubated in 50 mm phosphate buffer, pH 7.0, 2 m GdnHCl at 37 °C and 500 rpm in the absence or in the presence of seeds. A and B, kinetics of unseeded (A) and seeded (B) polymerization reactions of PrP^a (empty circles) and PrP^b (filled circles). C, lag phases for the kinetics of PrP^a (empty bars) and PrP^b (filled bars) plotted in A and B. D, lag phase of PrP^a (left) and PrP^b (right) aggregation process in the presence of 0.01, 0.1, 0.5, or 2% preformed homologous fibrils. The fibril formation process was followed by ThT fluorescence, and the lag phase was estimated as the intersection of quadratic and exponential fitting curves as described under ”Experimental Procedures.“ Three replicates were plotted for each reaction. Error bars indicate ± S.E.