Fig. 4. Thiol labeling supports the existence of the predicted cryptic pocket.

A Structure of the DTNB-labeling reagent. B Structure of VP35’s IID highlighting the locations of the four native cysteines (sticks). C307 and C326 are both buried and point into the predicted cryptic pocket. C Observed labeling rates (circles) for WT VP35 at a range of DTNB concentrations. Fits to the Linderstrøm–Lang model are shown in dashed colored lines and the expected labeling rate from the unfolded state is shown as black dotted lines. The mean and standard deviation from three replicates is shown but error bars are generally smaller than the symbols. D Observed labeling rates (circles) for VP35 C247S/C275S. Fits to the Linderstrøm–Lang model are shown in dashed colored lines, and the expected labeling rate from the unfolded state is shown as black dotted lines. The mean and standard deviation from three replicates is shown but error bars are generally smaller than the symbols. Source data are provided as a Source Data file.