Fig. 3.
Amyloid fibril formation by wild-type PI3-SH3 and PI3-KK mutant. Samples were prepared as in Fig. 2. (A) Binding of Congo red (Left) and Thioflavin-T (Right) by wild-type PI3-SH3 (•) and PI3-KK mutant (○) samples. The contribution of the dyes were subtracted from the spectra. (B) Electron micrographs of 1:10 diluted samples of wild-type PI3-SH3 (Left) and PI3-KK mutant (Right). (Scale bar, 100 nm.) (C) Cell viability in the presence of PI3-SH3 and PI3-KK proteins preincubated in 50 mM acetate buffer, pH 5.5, containing 25% (vol/vol) trifluoroethanol (13) at the protein concentrations indicated. Black bars refer to wild-type PI3-SH3, and white bars refer to the PI3-KK mutant. Values are normalized to those of control cells treated with medium alone.