Purification and biochemical study of viriditoxin, tissue damaging toxin, from prairie rattlesnake venom

Rattlesnake poisoning frequently produces a severe tissue damaging effect including myonecrosis and hemorrhage. In this investigation, viriditoxin was isolated from the venom of the prairie rattlesnake (Crotalus viridis viridis), and its chemical properties and biological activities associated with tissue damage were investigated. The toxin has a molecular weight of approximately 115 000 with an isoelectric point of 4.8. Amino acid composition analyses indicate that the toxin consists of approximately 1018 residues with high content of acidic amino acid residues. Circular dichroism was used to examine the conformation of viriditoxin. Although there is some indication of a high beta-sheet content, it is not possible to identify the exact conformation due to the anomalous CD spectra. Viriditoxin has both myotoxic and hemorrhagic activities. High serum creatine kinase activity of mice injected with the toxin substantiates the destructive action of viriditoxin on muscle. Viriditoxin has an LD50 value of approximately 5.0 microgram/g in mice indicating the protein is also moderately lethal in addition to its tissue damaging effect.