Permeability to Na⁺ and Ca²⁺ of the wild type NaChBac (LESWAS) ion channel and its mutants (LASWAS and LEDWAS). (A) Representative whole cell current vs. time records obtained for channels in bath solution containing 140 mM Na⁺ (left) or 100 mM Ca²⁺ (right). (B) Current–voltage I–V relationships (± SEM are shown as bars, n = 6 −12)) for LESWAS in Na⁺ solution (red squares) and Ca²⁺ solution (red triangles) and LEDWAS in Na⁺ solution (green squares) and Ca²⁺ solution (green triangles) normalized to the maximal peak Na⁺ current from the same cell. (C) Permeability Na⁺/Ca²⁺ ratios determined using reversal potentials, as described in [30], indicate that LEDWAS is a Ca²⁺ selective channel.