Figure 1.

Zn²⁺ promotes Aβ oligomerization. (A,F) ThT assay of Aβ in the absence or presence of Zn²⁺. Aβ or Aβ42 (F) at 50 µM was incubated with and without equal molar concentration of Zn²⁺. The final ThT concentration in the working solution is 5 µM. ThT fluorescence was monitored at 25 °C. (B,G) TEM images of the end-point products of Aβ alone or ZnAβ. The scale bars are 100 nm. (C–E) and (H–J) Far-UV CD spectra of Aβ40 and Aβ42. The spectra were scanned from 250 to 190 nm at the indicated time. Aβ40 in the absence (C) and presence of Zn²⁺ (D) after different incubation time are shown. The single wavelength changes of Aβ40 at 200 and 220 nm after addition of Zn²⁺ are shown in panel (E). Aβ42 in the absence (H) and presence of Zn²⁺ (I) were also monitored. The single wavelength changes of Aβ42 at 200 and 220 nm after addition of Zn²⁺ were shown in panel (J).