Figure 5
From: Amyloid-like aggregates of neuronal tau induced by formaldehyde promote apoptosis of neuronal cells
Conformational changes of polymerized tau in formaldehyde solution. (A) Circular dichroism spectra of 2 μM native tau (curve 2), and tau incubated with 0.1% formaldehyde (curve 1) or acetaldehyde (curve 3) at 37°C for 24 h. Scattering contributions of the aldehyde were subtracted from the spectra. (B) Changes in the fluorescence of tau in the presence of ANS. Tau (1.2 μM final concentration) was incubated in 100 mM phosphate buffer (pH 7.2) with or without 0.1 % aldehyde at 37°C overnight and then ANS (molar ratio: tau/ANS = 1/40) was added. Changes in the ANS fluorescence spectra at 480 nm for tau incubated with formaldehyde (curve 1), acetaldehyde (curve 3) or without aldehyde (self-aggregation, curve 2) were measured by excitation at 350 nm. Formaldehyde alone (curve 4) is shown as a control.