Proposed folding pathway of chymotrypsin inhibitor. Local regions with sufficient structural preference tend to adopt their favored structures initially (1). These structures come together to form a nucleus with a nativelike, but still mobile, structure (4). This structure then fully condenses to form the native, more rigid structure (5).
[From A. R. Fersht and V. Daggett. Cell 108:573–582, 2002; with permission from Elsevier.]