Figure 7.

The G466A/V467G mutations reduce block of intracellular tetraalkylammonium cations. Data shown from inside-out patches with reagents at indicated concentrations. Currents at +80 mV before and after exposure to blocker are superimposed. Dose–response relationships are shown in the bottom panels with molecular models of the blockers on the right. Data were fit using a single-site blocking model with K _d values of 3.77 μM (TBA) and 1.72 μM (TPentA) for WT channels, and K _d values of 730 μM (TBA) and 27.6 μM (TPentA) for G466A/V467G (n = 3–5).