Fig. 2  Sample chevron plots for FADD DD. WT (black) and some mutants, such as Y133A (blue), have straight folding and unfolding limbs; other mutants, such as I104A (red), have clearly curved unfolding limbs. This is not a reflection of stability, i.e. the length of the unfolding limb; I104A and Y133A have similar [urea]50% values. Chevron plots for all mutants are included in the Supplementary Data.