FIGURE 6.

A, evolution of compounds starting from CcoTx1 up to the rationally engineered multiple mutants (top-right corner). Selectivity to Nav1.2 and Nav1.6 is reported on the axis and potency is illustrated in nm on the plot. Effect of D1Z/M5I/K18Y/R24K,a and D1Z/M5I/R27N,a on human (B) Nav1.4 and (C) Nav1.5. The microprotein activity was tested at a concentration of 1000 and 3000 nm and percent inhibition was measured. Even at 3000 nm neither microprotein reached 50% inhibition on either channel, giving better than 1000-fold selectivity (hNav1.7 potency of these microproteins is ∼2.7 nm; A).