Temperature dependence of the preexponential αi and τi for triexponential fits for wild-type (top) and mutant (bottom) proteins. Long lifetime (●), medium lifetime (▲), and short lifetime (■) are given. In the lifetime profiles (right), the dashed lines are the temperature-dependence profiles from the global Arrhenius analysis (see Discussion). For the wild-type, these dashed lines are for Ea,1 = 1.0 kcal/mol and A1 = 0.987 ns−1 for τ1; Ea,2 = 1.76 kcal/mol and A2 = 8.54 ns−1 for τ2; and Ea,3 = 4.0 kcal/mol and A3 = 1901 ns−1 for τ3.