Chemical unfolding of apoA-I variants.

<p>Dark circles represent the experimental data for Wt. Gray and white symbols correspond to Lys107-0 and Gly26Arg respectively. A) Equilibrium unfolding of apoA-I variants as followed by intrinsic Trp fluorescence. Spectral centers of mass are plotted as a function of [GndHCl]. Final protein concentration was 0.1 mg/mL; excitation was set at 295 nm and emission recorded between 310 and 420 nm. Continuous lines are fits to the data, in the same order using a sigmoidal model. B) Dependence of bis-ANS fluorescence as a function of [GndHCl]. Proteins were diluted to 0.1 mg/mL and incubated with bis-ANS at a molar ration probe: protein 1∶5. GndHCl was added stepwise. Fluorescence was registered as the Wavelength of Maximum Fluorescence at each [GndHCl]. C) Overlap of GndHCl-mediated denaturation curves for Wt apoA-I as followed by Trp (panel A) and bis-ANS fluorescence (panel B).