Fig. 5. Aβ_16–22and Aβ₄₀do not co-assemble during co-aggregation.

Negative-stain TEM analysis of Aβ₄₀ incubated for 24 hours in the (A) absence or (B) presence of Aβ_16–22. Scale bars, 200 nm. (C) PIC of mixtures of diazirine-labeled Aβ_16–22 (Aβ*_16–22) and Aβ₄₀ incubated for 24 hours and then irradiated for 30 s. Only homomolecular Aβ_16–22 cross-links are observed, indicating that the fibrils are not copolymerized at the end of the reaction (the inset depicts the mechanism of PIC of the diazirine group. (D) DMD simulation snapshots of co-aggregation of Aβ₄₀ (blue) and Aβ_16–22 (red) indicate that separate homomolecular oligomers are formed at t = 202 μs.