Figure 2.

Fibril formation of Aβ40-Iowa, Dutch and Dutch-Iowa mutants involves a transient anti-parallel non-fibrillar intermediate. Time courses of fibril formation from monomeric Aβ40 peptides at 37 °C are shown using thioflavin T fluorescence (a–c), circular dichroism (d–f) and FTIR (g–i) spectroscopy. The time courses for the mutant peptide for fibril formation monitored by thioflavin T fluorescence at 490 nm is much more rapid than for Aβ40-WT. However, for each peptide when labeled with 1-¹³C Gly33, there is observation of a β-hairpin intermediate as fibrils form.