Gating-modifier toxin that targets voltage-gated sodium channels. Inhibits the inactivation of Nav1.7/SCN9A. Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. Exists in two forms, due to cis-trans isomerization at 33-Asp-Gly-34. The cis isomer also acts by shifting activation of the Nav1.7/SCN9A channel to more depolarized voltages.