Figure 4.

The H/D-exchange protection profile of unfolded ubiquitin in 6 M GdmCl, represented by P as a function of the residue number (pH* 3.3 and 15 °C). The dashed lines indicate the P values of 2 and 3. The amino-acid residues with P values larger than 2 and 3 are indicated in pink and red, respectively, and the other residues in black. The locations of the secondary structures in native ubiquitin (PDB code: 1UBQ) are shown by arrows (β-strands) and open rectangles (helices). The k_obs values for the majority of NH protons were obtained by three independent H/D-exchange experiments, and the percent standard error estimate of k_obs was ~8%, indicating that the P value of 2.0 can be written as P = 2.0 ± 0.16 (see [136] for the complete list of the standard error estimates of k_obs values). Adapted with permission from Ref. [136]. Copyright 2020 Biophysical Society.