Figure 4.

Intrinsic fluorescence spectra (λ _ex 280 nm) of urea-denatured C2α domain (a) and C2β domain (b) diluted in a Tris/HCl buffer containing (red curves) or not (blue curves) 8 M urea and after 1 h of incubation at room temperature. The final concentration of both domains was set at 1 μM, leading to a final concentration of urea ranging from 50 mM to 75 mM for blue curves. Fluorescence intensity was expressed in arbitrary units (AU) and bandwidths were set at 10 nm for both excitation and emission.