Fig. 4.

Thermodynamic and structural stability of the binary complex. (A) Far-UV CD spectra of PGC1α220 (red), ERRγLBD (blue), and binary complex (pink). Spectra were normalized to molar ellipticity, secondary structure was quantified using CDFIT and summarized in Table 2. (B) Thermal denaturation of ERRγLBD (●) and binary complex (▪). The CD signal at 222 nm was monitored as a function of temperature. (C) Chemical denaturation ERRγLBD (●) and binary complex (▪). Intrinsic tryptophan fluorescence was monitored as a function of increasing urea concentration. T_m and D_m values were calculated as described in Materials and Methods and are summarized in Table 3.