FIGURE 2.
A single R4A/R5A mutant subunit is sufficient to accelerate rate of hERG1 channel deactivation. A, voltage clamp pulse protocol and currents conducted by R4A/R5Amonomer and concatenated tetrameric channels as indicated. B, voltage dependence of activation for indicated channels. Normalized tail currents were plotted as a function of Vt and fitted to a Boltzmann function (smooth curves) to estimate V0.5 and z (summarized in Table 1). C and D, τdeact-f and τdeact-s and relative current amplitudes for both components plotted as a function of Vret for the indicated channels.