Capacitance and polarizability of the protein also additively combine in the dominant term in the separation dependence of the fluctuation interaction between two identical proteins, which differs from the original KS form. The relative contribution of the two is further weighted by the screening length of the bathing solution. Figure shows the scaled strength of the fluctuation interactions 1+κ 2 δp 2 / δq 2 [see Eq. (26)] on the example of calmodulin for different values of ε ∞ and n 0 . Regardless of these two parameters, polarizability of the protein appears to be the dominant contribution to the interaction. The relative contributions of charge and dipole fluctuations are modified by changes in ε p and n 0 , somewhat more so by the latter. And while the relative contributions of polarizability and capacitance to the fluctuations differ from protein to protein (Fig. in the SI), the former is always dominant.