Figure 4: Frataxin folds following different pathways from the cold and hot denatured states.

(a) Schematic representation of the cold and hot folding pathways along the fraction of native contacts Q. The structural ensembles shown correspond the most populated microstates in the two denatured states, the two transition states and the native state. (b) Contact maps for the cold denatured, native and hot denatured states; the color code corresponds to the fraction of contact formation. The contact map of the cold transition state (upper half) and the cold denatured states (lower half) is shown on the left, the contact map for the native state in the middle, and the contact map of the hot transition state (upper half) and the hot denatured states (lower half) on the right. (c) Brønsted plots determined at 287 K and 323 K from mutagenesis (see Methods). At low temperature the data are more linearly correlated than at high temperature, corresponding to a higher degree of structure in the cold transition state than in the hot transition state, as reported by the corresponding values of Q (insets).