MONDAY, Feb. 28, 2005 (HealthDay News) -- Snake venom is one of nature's most sophisticated bioweapons, containing toxins that cause their victims' bodies to turn against themselves.
Now scientists have found the reason why these poisons are so potent: They're made of altered proteins from body tissues located throughout the snake's body.
The findings might even help researchers someday turn deadly venoms into lifesaving medicines.
The new study, published in the March issue of Genome Research, provides the first comprehensive analysis of the origin and evolution of snake venoms.
Research conducted by Bryan Grieg Fry, of the University of Melbourne, Australia, has identified the origin of all 24 known types of snake toxin.
Although snake venom is transferred through bites, scientists have doubted the venoms are saliva-based. Instead, the theory was that snakes recruit and alter proteins for their chemical arsenal from other body tissues.
Fry's research has proven that point, demonstrating that 21 of the 24 known venoms are derived from proteins normally expressed in other body tissues. The identified origin tissues are found in the brain, eye, lung, heart, liver, muscle, mammary gland, ovary and testis of snakes.
Of the three remaining venoms, two toxin types are derived from proteins presumably expressed in ancient reptile saliva, while the third did not exhibit any similarity to known proteins.
"The wide-ranging origins of snake venom toxin from body counterparts explains the amazing diversity of ways that venomous snakes can kill their prey and why they have so much potential use in medical research," Fry said.
Fry hopes his findings will aid research focused on the use of snake toxins for therapy and treatment of diseases, including cancer, arthritis and heart disease.
"The natural pharmacology that exists within animal venoms is a tremendous resource waiting to be tapped," he said.
Venom-based research may already be bearing fruit. In August, scientists at Wake Forest University used a protein in snake venom to help elucidate why heart medications called integrin antagonists can sometimes cause patients more harm than good.
More information
The U.S. Food and Drug Administration has more about treating snake bites.
