Figure 2.

Thermodynamic functions of collapse calculated from smFRET results for four different proteins. Values of the free energy of collapse, − ΔG_{U →C}, as a function of denaturant concentration, are shown as green triangles. The enthalpic contributions −ΔE_{U →C} and the entropic contributions k_BT · ΔS_{U →C} are shown as black squares and red circles, respectively. The interpolated value of each thermodynamic function at D₅₀ is subtracted from all points. Solid lines show the denaturant dependence of the free energy of folding, ΔG_{U →N}, as published in the literature. A. Results for protein L denatured in GdmCl (labeled 4a in Table 1). B. Im9 denatured in urea (3 in Table 1). C. CspTm denatured in GdmCl (2a in Table 1). D. Barstar denatured in GdmCl (1a in Table 1).