Figure 2.

(a) Thermal refolding of the β-hairpin in a spherical pore with the radius R_s = 4.6a. The black and gray thick solid lines represent the fractions of the native contacts f and the HBs f, respectively. The black thin solid line refers to the radius of gyration <R>. Dashed curves correspond to the quantities of the bulk hairpin. Comparison of the curves for the encapsulated and bulk β-hairpins shows that confinement eliminates expanded conformations and stabilizes the folded state (see text for details). (b) Dependence of the folding rates k_F (●) and the fraction of fast trajectories Φ (○) on R_s. Encapsulation generally accelerates folding rates. A nonmonotonic dependence of k_F on R_s reflects changes in the mechanisms of β-hairpin formation in small pores. The solid line is drawn as a guide to the eye. The arrows mark the bulk values k = 47 μs⁻¹ and Φ^b = 0.89.