Figure 2: Equilibrium unfolding of HIV-1-PR1-95. Top: mean residue ellipticity at 230 nm of a 15 µM HIV1- PR1-95 in 20 mM sodium phosphate, pH 6, measured in the presence of increasing concentrations of urea (left), GdmCl (middle) and acetic acid (right) at 25 °C. Bottom: wavelength of maximum fluorescence emission of 4 µM mHIV-1-PR1-95 sample 20 mM sodium phosphate buffer, pH 6, measured in the presence of increasing concentrations of urea, GdmCl or acetic acid, at 25 °C (excitation wavelength: 295 nm).