8.B.17 The Sea Anemone Peptide Toxin Class III (ShI) Family
Cnidaria (sea anemone, coral, jellyfish, and hydroid) toxins target voltage-gated sodium and potassium channels. The sodium channel toxin is a member of the Toxin-4 Superfamily. It binds specifically to the sodium channel (Nav), thereby delaying its inactivation during signal transduction. Thus it strongly stimulates mammalian cardiac muscle contraction.These toxins are reviewed by Moran et al., 2009. Cnidarian toxin families, including peptide neurotoxins (voltage-gated Na+ and K+ channel-targeting toxins: NaTxs and KTxs, respectively), pore-forming toxins (actinoporins, aerolysin-related toxins, and jellyfish toxins), and the newly discovered small cysteine-rich peptides (SCRiPs).
The Sea Anemone peptide type III neurotoxin, ShI (Fogh et al., 1990), 3-d structure known (1SHI-A).
Sh1 of Stoichactis helianthus (P19651)
Sea Anemone peptide neurotoxin Am-3; blocks Na channels.
Am-3 of Antheopsis maculata (P69928)
Anthopleurin-A, AP-A, a heart stimulant; binds voltage-gated Na+ channels (structure known) (Frazão et al. 2012).
AP-A of Anthopleura xanthogrammica (P01530)