Thermal unfolding of full-length RIα monitored by CD spectroscopy.

<p>(A) Far-UV CD spectra at 25°C of apo-RIα, stripped of endogenously bound cAMP (red solid line), RIα-cAMP, with excess (143 µM) cAMP (black line), and of apo-RIα at 75°C (red dashed line). The CD spectrum taken at 25°C after heating apo-RIα to 95°C is similar to that shown by the red dashed line. (B) Temperature dependence of the ellipticity at 222 nm at 1.5°C/min scan rate, for apo-RIα (red) and cAMP saturated RIα (black). Further details are provided in the Experimental section. MRW, mean molar residual ellipticity. All experiments were performed with 2 µM full-length RIα protein.