Figure 2.

The effect of the DOL of N-terminus-bound fluorophores on oligomer size distributions of Aβ40. (A, B, D, and E) Oligomer size distributions in terms of relative photon number, $N_{phot,rel}=N_{phot}/{\overline{N}}_{phot,mon}$, using 100% (A and D) and 5% (B and E) of labeled Aβ40 peptides is shown. The oligomer distributions are shown before (black) and after (colored) 4 h of incubation for Atto488-Aβ40 (blue) and HL647-Aβ40 (red). The last bar in the histograms sums up all oligomers above N_phot,rel > 50. (C and F) The distributions of the fluorescence lifetimes, τ_F, before (black) and after (colored) 4 h of incubation for Atto488 (blue) and HL647 (red). The dashed line in (F) displays HL647-Aβ40 dissolved at pH 9.2; all other measurements were conducted at pH 7.5. The burst selection criteria were chosen such that the probability to include monomers in the histograms is very low. To see this figure in color, go online.