Impact of the domain 3 pore loop on Tz1-induced channel modulation. (A; left) Representative current–voltage plots of 44p(1.7)4 before (open circles) and after the application of 5 µM Tz1 (closed symbols) without (gray) or with (black) a preceding prepulse. Control data are shown without a prepulse, as they are indistinguishable from those with a prepulse. Continuous curves are data fits according to Eq. 1. (Right) Current traces from the same experiments as shown on the left obtained at the indicated potentials in the absence (thin black) and presence of Tz1 without (gray) and with (thick black) a prepulse. (B) Similar experiments as in A for mutant 44p(1.7)4–G658N.