Figure 4. pH titration of UbL50E from pH 4 to pH 7.8.
a) Representative resonance which shifts and then disappears due to exchange broadening. b) In the pH 6.2 to 7.8 range, some resonances move while others do not (right panel). c) Resonances classified as non-moving if their chemical shift remained unchanged from pH 6.2 to 7.8 (red box). d) The three classes of behavior of UbL50E peaks are mapped onto the structure: unchanged (blue), changed (magenta), and chemical shift changed with peak disappearing at neutral pH due to exchange broadening (orange).