SAXS detected HP unfolding of the I7A and L139A variants of pp32. (A and B) Pressure-dependent pair distance distribution [P(r)] plots for pp32 L139A (A) and I7A (B), respectively, obtained from fits of the pressure-dependent scattering profiles Increasing pressures are from blue to red. For L139A, blue corresponds to atmospheric pressure, cyan to 0.4 kbar, green to 0.8 kbar, orange to 1.2 kbar, red to 1.6 kbar, and brown to 2.0 kbar. For I7A, blue corresponds to atmospheric pressure, cyan to 0.7 kbar, green to 1.4 kbar, orange to 2 kbar, pink to 2.8 kbar, and red to 3.5 kbar. (C) Radius of gyration as a function of pressure for L139A (blue) and I7A (red).