Figure 3.

(A) Ca²⁺ and Cs⁺ current (black lines, left axis) and number of Ca²⁺ and Cs⁺ in the selectivity filter (red lines, right axis) as [Ca²⁺]_lum is increased. The net current is shown with the dotted line and the experimental results are shown with gray squares. (B) The resistances of Cs⁺ (solid lines) and Ca²⁺ (dashed lines) in the selectivity filter (black lines), the cytosolic and luminal vestibules (blue lines), and the baths (green lines). (C and D) Same as panels A and B with Li⁺ substituted for Cs⁺. The applied voltage is 10 mV.