Structural and biological aspects of the Micrurus pyrrhocryptus venom

JC DOKMETJIAN; S DEL CANTO; MIRTHA BISCOGLIO DE JIMÉNEZ BONINO

Valencia

Congreso; 17th Congress of the European Section of the International Society on Toxinology; 2011

International Society of Toxinology

Snake venom toxicity is the consequence of the combination of venomous peptides and proteins whose identification and characterization are of great importance to understand envenomation and develop new clinical treatments. Venom composition varies between families, from genus to genus and even between species. The Elapinae subfamily includes coral snakes whose bite causes mailnly neurotoxic effects which disable muscle contraction, paralyse the heart and inhibit respiration in severe cases. Alfa-neurotoxins are capable of reversibly blocking the nerve transmision by competitively binding to the nicotinic acetylcholione receptor (AChR) located at the neuromuscular endplate. Post-synaptic neurotoxins, mainly those belonging to the three-fingers group, are widely distributed in Elapidae snake venoms and that is why envenoming shows highly neurotoxic strategies. Micrurus is the most representative genus of Elapinae subfamily as regards abundance and diversity. However, the structure-function relationship of the venom of only a few species have been investigated. We herein report biological aspects of the Micrurus pyrrochryptus venom sush as LD50, Hemorrhagic, necrotic, congulant and hemolytic activity as well as the ability of venom components to compete with alfa-Bungarotoxin for the ligand-binding site of the AChR. We also report the determination of the molecular mass and N-terminal sequence of toxins including PLA2 s, short, long and weak neurotoxins. The complete sequence of one of the short neurotoxins was also obtained this being the first sequence of an Miocrurus alpha-neurotoxin and one of the few fully determined in members of the genus. This is a contribution to the snake venom basic research and to the antivenom production strategies.