FIGURE 2.

TEM images of Aβ(1–42) fibrils formed in the absence (a) and presence (b) of Cu²⁺ ions. The morphologies of fibers formed with and without Cu²⁺ ions present are similar; typically long, straight, unbranched fibers are observed often stacked together. Scale bar, is 50 nm. The negatively stained fibers are generated from 3 μm Aβ(1–42) with and without 0.5 mol eq of Cu²⁺ ions, over 200 h with agitation every 30 min, at 30 °C in 50 mm HEPES, 160 mm NaCl. The fibrils were then freeze-dried to ∼0.5 mg/ml.