FIGURE 6.

Oligomerization and fibrillization of Aβ in the presence of the metal ions monitored by ThT and dot blotting. Aβ in the absence (black line) and presence of various concentrations of Zn²⁺ (A), Cu²⁺ (B), Fe³⁺ (C), and Al³⁺ (D) are shown. From lowest to highest, the ion concentrations are labeled with blue, green, orange, pink, and red lines. The concentrations examined were 5, 12.5, 25, 50, and 200 μm for Zn²⁺ and Cu²⁺; 25, 50, 100, 150, and 200 μm for Fe³⁺; and 25, 50, 100, 250, and 500 μm for Al³⁺. Time courses of Aβ in the presence of different metal ions were examined by dot blotting probed by anti-amyloid oligomer antibody, A11. The results are shown at the lower portions of each panel. Zn²⁺ accelerated Aβ aggregation without a lag phase but promoted oligomers formation with a Zn²⁺ concentration dependence. Cu²⁺, Fe³⁺, and Al³⁺ prolonged the lag phase with ion concentration dependence, where Al³⁺ at lower concentrations also promoted oligomer formation.