Potent voltage-gated sodium channel blocker (By similarity). Potently inhibits the voltage-gated sodium channels Nav1.7/SCN9A (IC(50)=0.58-10 nM) (By similarity). Shows a moderate activity on Nav1.1/SCN1A (IC(50)=6 nM), Nav1.2/SCN2A (IC(50)=5-128 nM), Nav1.3/SCN3A (IC(50)=20.3-170 nM), and Nav1.6/SCN8A (IC(50)=17-20.1 nM) (PubMed:29703751) (By similarity). Shows an unclear inhibition of Nav1.4/SCN4A (IC(50)=200 nM to >10 uM), Nav1.5/SCN5A (IC(50)=140 nM to >10 uM) and Nav1.8/SCN10A (IC(50)=68-12200 nM) (PubMed:29703751) (By similarity). Weakly blocks the low voltage-gated calcium channels Cav3.1/CACNA1G (30% inhibition of the peak current by 9.8 nM of the toxin) (PubMed:21740921). It shows moderate affinity for lipid bilayers (PubMed:29703751). Expressed by the venom gland. The presence of a 'disulfide through disulfide knot' structurally defines this protein as a knottin. This toxin is amphipathic in nature with a hydrophobic face on one side of the molecule (composed of residues 51-Phe-Met-52 and 73-His--Phe-80) and a hydrophilic (mostly cationic) face on the opposite side (composed of residues 56-Ile--Lys-61 and 64-Arg--Pro-65). Monoisotopic mass (after thiol reduction). The primary structure of the mature peptide is identical to that of GpTx-1 from Grammostola porteri (AC P0DL72) and Gtx1-15 from Paraphysa scrofa (AC P0DL73). Belongs to the neurotoxin 10 (Hwtx-1) family. 08 (Gtx1-15) subfamily.