Figure 4.

Transition states of forced unfolding of the RGD-loop apex. Three distinct regions of φ–ψ combinations of Asp⁸⁰ are observed during the extension of FnIII₁₀, leading from β-turn II′ (38) to a more linear conformation. The extension at the two transition points also is shown. The two-dimensional plot is continuous at the edges because −180° and +180° rotations are equivalent.