Gating-modifier toxin that inhibits voltage-gated sodium channel Nav by shifting the threshold for channel activation to more positive potentials. This toxin moderately inhibits human Nav1.7/SCN9A (IC(50)=459 nM) and weakly inhibits hNav1.2/SCN2A and hNav1.5/SCN5A (<20% inhibition at 1 uM peptide). Inhibition of Nav1.7 is voltage-dependent, with lower inhibition at more positive test pulses