Channelpedia

PubMed 12827284


Referenced in: none

Automatically associated channels: Kir6.2



Title: Isolation and characterization of hainantoxin-IV, a novel antagonist of tetrodotoxin-sensitive sodium channels from the Chinese bird spider Selenocosmia hainana.

Authors: Z Liu, J Dai, Z Chen, W Hu, Y Xiao, S Liang

Journal, date & volume: Cell. Mol. Life Sci., 2003 May , 60, 972-8

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/12827284


Abstract
A neurotoxin, named hainantoxin-IV, was purified from the venom of the spider Selenocosmia hainana. The amino acid sequence was determined by Edman degradation, revealing it to be a 35-residue polypeptide amidated at its C terminal and including three disulfide bridges: Cys2-Cys17, Cys9-Cys24, and Cys16-Cys31 assigned by partial reduction and sequence analysis. Hainantoxin-IV shares 80% sequence identity with huwentoxin-IV from the spider S. huwena, a potent antagonist that acts at site 1 on tetrodotoxin-sensitive (TTX-S) sodium channels, suggesting that hainantoxin-IV adopts an inhibitor cystine knot structural motif like huwentoin-IV. Under whole-cell voltage-clamp conditions, this toxin has no effect on tetrodotoxin-resistant voltage-gated sodium channels in adult rat dorsal root ganglion neurons, while it blocks TTX-S sodium channels in a manner similar to huwentoxin-IV, and the actions of both toxins on sodium currents are very similar to that of tetrodotoxin. Thus, they define a new family of spider toxins affecting sodium channels.