<p>Kinetic traces (A and C) and residuals (B and D) of unfolding (A; B) and refolding (C;D) transitions of αTh (closed circles) and αTh-PPACK (open circles). The curves were fit with a single exponential decay, and the rate constant was calculated. Fitting residuals are shown for αTh (closed circles) and αTh-PPACK (open circles); (E) Chevron plot – GdmCl dependence of the apparent rate constant of folding and unfolding of αTh and αTh-PPACK. The lack of linearity in the Chevron plot indicates a kinetic mechanism more complex than a simple two-state model, and thus limits a precise quantitative analysis of the kinetic process. (F) The dependence of the refolding lag phase as a function of GdmCl. (G) Temperature dependence on the kinetics of GdmCl-induced unfolding of αTh and αTh-PPACK by jumping the GdmCl concentration from 0 to 4 M and monitoring by the changes in fluorescence intensity, as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0024735#pone-0024735-g004" target="_blank">Fig. 4A</a>. Lines represent the best fit with Eq 22. Details in the <i>Experimental Methods</i> section.</p
