BIOCHEMICAL, PHARMACOLOGICAL AND GENOMIC CHARACTERIZATION OF TS-IV, AN ALPHA-TOXIN FROM THE VENOM OF THE SOUTH-AMERICAN SCORPION TITYUS-SERRULATUS

The venom of the scorpion, Tityus serrulatus, was fractionated to inve stigate the chemical and pharmacological properties of its alpha-toxin content. Three alpha-toxins (Ts III, Ts IV and Ts V) were purified by conventional chromatography (gel filtration and ion-exchange chromato graphy), followed by immunoaffinity chromatography. Competition experi ments using reference alpha- and beta-toxins suggested that these alph a-toxins were contaminated with around 0.01% of beta-toxin. The sequen ce of the first 30 amino acids of Ts IV was established. Using an olig onucleotide probe, a cDNA encoding its precursor was cloned from a ven om gland cDNA library. The primary structure deduced from the cDNA nuc leotide sequence provides possible explanations for the polymorphism o f these three molecules.