Figure 3.
Typical kinetic hydrogen-deuterium exchange data measured by NMR. HX rate constants (kex) were determined by uniexponential fitting of the time-dependent decrease in resonance amplitude and translated into free energy values for the determining structural opening reaction by use of Eq. 1. Exchange of the different NHs could be moved into a convenient time window by adjusting pD between 6.5 and 9.4, made possible by the invariance of unfolding ΔG with solution pD. Nonunit amplitudes are due to partial overlap (Cys-8) and dead time losses (Tyr-10).