Figure 2.

Urea denaturation curves of spectrin as monitored by fluorescence and CD measurements: (A) Fluorescence emission maximum (open circles) and ellipticity at 222 nm (filled circles), and (B) fluorescence emission maximum (open circles), and fluorescence emission intensity ratio (filled circles) at 337 and 350 nm (F₃₃₇/F₃₅₀) are plotted as a function of urea concentration. The excitation wavelength was 295 nm for fluorescence measurements. The concentration of spectrin was 0.05 μM for fluorescence measurements and 0.24 μM for CD measurements. See Materials and Methods for other details.