Fig. 5

Aβ2-40 shows increased aggregation propensity and could seed the aggregation of non-truncated Aβ. Aggregation of synthetic Aβ peptide (truncated Aβ2-40 and non-truncated Aβ1-40) variants were monitored by Thioflavin T (ThT) fluorescence assay during incubation at 37 °C for 24 h (a). The aggregation assay was performed in 50 mM sodium phosphate buffer and a final Aβ concentration of 50 μM. The truncated Aβ2-40 peptide demonstrate a shorter lag phase and rapid aggregation behavior as compared to non-truncated Aβ1-40 variant. b Demonstration of the seeding capacity of Aβ2-40 peptides. Aggregation of Aβ1-40 with and without preformed oligomeric nuclei of Aβ2-40 was monitored by ThT fluorescence assay. Initial aggregate formation is accelerated by the addition of the Aβ2-40 seeds, as indicated by the reduced lag phase. The graphs on the right-side in (a) and (b) display the same results with extended time scale to demonstrate the differences in the lag phase. The differences are statistically significant. For Unpaired t test and F test, the P value is < 0.0001