Figure 5.

Mutation of several residues in the pore turret of CNGA2 cause modest changes in PsTx affinity. (Top) Current traces obtained at −60 mV are shown for 2-E325K, CNGA2, and 2-S301F. Traces, in order of decreasing magnitude, represent currents measured in control solution, 25 nM Pstx, 50 nM PsTx, 100 nM PsTx, 500 nM PsTx, and 10 mM MgCl₂. (Bottom) Dose respose relations for PsTx inhibition of 2-E325K (123 μM), CNGA2 (32 μM), and 2-S301F (16 μM). Dose–response relations were fit by a modified form of the Hill equation with an n value of 1.0.