(A) fluorescence- and (B) far-UV CD-monitored unfolding transitions of Nank1-7* (×), Nank1-5C16-7 (○), and Nank1-5C26-7 (□). (C) Fluorescence- and (D) far-UV CD-monitored unfolding transitions of Nank1-5 (×),Nank1-5C1 (○), Nank1-5C2 (□), and Nank1-5C3 (▵). Solid lines represent fits of the data by two- (A, C, and D) and three-state models (B). Conditions: 25 mM Tris·HCl, 150 mM NaCl, pH 8, 20 °C.