A remotely related group of atracotoxins operate by opening
sodium channels.
Delta atracotoxin from the venom of the
Sydney funnel-web spider produces potentially fatal neurotoxic symptoms in primates by slowing the inactivation of
voltage-gated sodium channels.[2] The structure of atracotoxin comprises a core beta region containing a triple-stranded a thumb-like extension protruding from the beta region and a C-terminal helix. The beta region contains a
cystine knot motif, a feature seen in other neurotoxic polypeptides[2] and other spider toxins, of the CSTX family.
Spider potassium channel inhibitory toxins is another group of spider toxins. A representative of this group is
hanatoxin, a 35 amino acid peptide toxin which was isolated from
Chilean rose tarantula (Grammostola rosea,
syn.G. spatulata) venom. It inhibits the drk1
voltage-gated potassium channel by altering the energetics of gating.[3] See also
Huwentoxin-1.[4]
^Shimada I, Sato K, Takahashi H, Kim JI, Min HJ, Swartz KJ (2000). "Solution structure of hanatoxin1, a gating modifier of voltage-dependent K(+) channels: common surface features of gating modifier toxins". J. Mol. Biol. 297 (3): 771–780.
doi:
10.1006/jmbi.2000.3609.
PMID10731427.
Kim JI, Konishi S, Iwai H, Kohno T, Gouda H, Shimada I, Sato K, Arata Y (July 1995). "Three-dimensional solution structure of the calcium channel antagonist omega-agatoxin IVA: consensus molecular folding of calcium channel blockers". J. Mol. Biol. 250 (5): 659–71.
doi:
10.1006/jmbi.1995.0406.
PMID7623383.
