Figure 5. Native state hydrogen exchange on UbL50E I state at pD_read 7.5.

a) Hydrogen bond network with direction of bond (NH→ O=C) and K_eq noted. Arrows are color-coded according to their stability (red = global, yellow= 3₁₀ opening, orange = other, white = absent) while boxes are color-coded according to the type of chemical shift movement during the pH titration (adapted from Fig. 4). b) Representative NSHX denaturant dependent isotherms. Isotherms for protons on the 3₁₀ helix have lower DG_HX and m values compared to the rest of the isotherms. c) Histogram of ΔG_HX and m-values. The positions of the strands (blue), α- (red) and 3₁₀ helices (green) are noted at the top.