Mutant Enzymes Created Through “Artificial Selection” Protect Against Nerve Gas

Researchers at the Weizmann Institute of Science in Israel have successfully induced an artificial kind of “natural selection” to create enzymes that can protect animals against the effects of nerve gas. It’s almost an accelerated evolution–one that could help protect people from nerve agent poisoning using our own natural defenses as a starting point.

Agents such as nerve gas can cause death by suffocation by disrupting signals between nerve and muscle cells. The gas inhibits acetylcholinesterase, an enzyme responsible for the breakdown of a chemical messenger responsible for muscle control, which is how it causes much of its ill effects. Existing drugs for the treatment of nerve agent poisoning are only effective when faced with small doses of the nerve gas, and are known to have serious side effects, so some researchers are looking to enzymes that occur within our bodies. Using enzymes breaks down the nerve agents before they have a chance to bind to the body’s chemical messenger and prevents damage. However, naturally-occurring enzymes are too slow to be effective.

Enter Professor Dan Tawfik and his group. Their enzymes are specially selected to efficiently battle nerve gas. Starting with an enzyme already found in the human body (and found to be able to degrade nerve agent components), his team introduced mutation after mutation and scanned the results to find the most efficient new enzyme. The mutated enzymes were then put in a test tube with a small amount of nerve agent and the acetylcholinesterase. If the acetylcholinesterase continued to function normally, Tawfik concluded that the mutated enzyme had successfully degraded the nerve agent.

Tawifk and his team have been able to identify mutant enzymes capable of breaking down two different types of nerve agents. During experiments, these enzymes showed near-complete success as a preventative treatment against the nerve agents. The researchers are now working on increasing the number of nerve agents the enzymes can break down, and developing new, more efficient enzymes that could be injected after nerve gas exposure–the breakthrough could lead to better anti-nerve-agent salves than ever before.

Weizmann Institute of Science