A unified nomenclature for short-chain peptides isolated from scorpion venoms: alpha-KTx molecular subfamilies

Peptidyl toxins are used extensively to determine the pharmacology of ion c hannels. Four families of peptides have been purified from scorpion venom. In this article, the classification of K+-channel-blocking peptides belongi ng to family 2 peptides and comprising 30-40 amino acids linked by three or four disulfide bridges, will be discussed. Evidence is provided for the ex istence of 12 molecular subfamilies, named alpha-KTx1-12, containing 49 dif ferent peptides. Because of the pharmacological divergence of these peptide s, the principle of classification was based on a primary sequence alignmen t, combined with maximum parsimony and Neighbour-Joining analysis.