Relationship between permeability ratio and anion hydration energy in TMEM16A channels. Plotted values are the anion permeability ratios listed in Table 1 for the indicated channels. Hydration energy values are from Marcus (1997). In gray color, the radius of the anions (in Å) is indicated in gray. t, the SCN⁻ data was not included in the linear fit (continuous green line). The pink rectangle highlights the narrow range of permeability ratio values of the mutant channels.