Figure 1.

Conformational relaxation kinetics of bR in the folding transition zone. (A) The refolding of bR_U (red) and unfolding of bR_F (blue) monitored at X_SDS = 0.73 by the absorbance of the folded protein at 600 nm (A₆₀₀). The curve-fitting of the change of A₆₀₀ with eq 1 is shown in black lines. (B) Dependence of the observed rate constants on X_SDS. The natural logarithms of the rate constants of the fast (λ₁) and slow (λ₂) phases of conformational relaxation of wild-type (black) and L152A (blue) bR’s are plotted against X_SDS. Whether the values were obtained from unfolding or refolding is indicated in the figure. The rate of retinal hydrolysis (k_h; black line) is plotted for reference. (C) Dependence of the folding and unfolding rate constants on X_SDS. The natural logarithms of the rate constants for folding (k_f) and for unfolding (k_u) of wild-type (black) and L152A (blue) bR’s are plotted against X_SDS. Whether the values were obtained from unfolding or refolding is indicated in the figure.