Figure 2.
Distribution of thermally accessible states. Y(Nf) = Σi(Pi2), which represents the inverse number of thermally accessible states available to the system, was computed for all values of Nf, and the result for SH3 and γ repressor is shown. The sharp peak near Nf ∼ 0.8 for the SH3 domain (solid line) indicates a drastic reduction in the number of accessible states late in folding that is also seen for CI-2, barnase, and Che Y. By contrast, λ-repressor (dotted line) does not exhibit such a drastic reduction in accessible states, suggesting a more plastic folding mechanism.