FIGURE 7.

Representative single-channel currents of I323 mutations and their open and closed dwell-time histograms. (A) Representative single-channel currents as labeled were obtained from a series of 12 side-chain substitutions at the position 323 including the wild-type mSlo. All the currents were activated at +60 mV in the presence of 10 μM Ca²⁺. All the recordings were filtered at 10 kHz. Solid lines labeled with “c” and “o” represent the closed and open levels, respectively. (B) Both the open and closed dwell-time histograms for the I323 mutant series were fitted to biexponential functions as indicated. (C) The open probabilities of I323 mutants are plotted as functions of hydrophobicity of the candidate amino acids and then fitted to a Boltzmann function (Eq. 1).