The size of these objects all cluster around a diameter of 16 Å, roughly the size of damping seen in ddG and molecular models. Assuming the same density as bulk water, spheres of this fitted size would house around 60-90 water molecules each (calculations presented in Supplemental Information). The SAXS fitting parameters (Figure and) indicate that there is little change in micelle radius with increasing water content in the mixture (a very slight tendency towards increasing reverse micelle is evident), but there is a strong linear change in φfitted (Figure ; slope = 0.53 ± 0.03, R 2 = 0.992). This is in agreement with the xA-dependence of the ddG signal (Figure and), where the amplitude of ddG scales with the water content, indicating that more of the same objects are present with increasing amounts of water. Interestingly, the slope of the fit, 0.53, indicates that the volume occupied by the inverse micelles grows at roughly half the nominal water volume fraction (assuming additive mixing).