Scorpions from the primeval subgenus Archaeotityus produce putative homologs of Tityus serrulatus toxins active on voltage-gated sodium channels

it has been proposed that the subgenus archaeotityus comprises the most ancient species group within the medically important scorpion genus tityus. cdna encoding sodium-channel active toxins from the type species of this subgenus, tityus clathratus (central venezuela), have been isolated and sequenced. two cdnas were retrieved that encoded 61 amino acid-long putative neurotoxins named tcl1 and tcl2. sequence identity was highest (87%) when both were compared with β-toxin ts1 from the brazilian scorpion tityus serrulatus and its homologs from t. bahiensis, t. stigmurus, and t. costatus. a bayesian analysis indicated statistical support for the grouping of t. clathratus tcl1 and tcl2 with brazilian gamma-like β-toxins, reinforcing previous phylogenetic studies which suggested an evolutionary relationship between the subgenus archaeotityus and scorpion species inhabiting southeast south america belonging to the subgenus tityus.