Engineered Yeast Produces Viper Venom

... for use as an anticlotting medicine
Kalyan Varma

Put snake genes in yeast and what do you get? Believe it or not, you get a blood-clot-fighting medicine based on snake venom, according to a study published recently in Scientific Reports.

In the wild, the pit viper Agkistrodon acutus has a reputation for being deadly—sometime it’s called the “five pace” because those bitten collapse after just a few steps. But in the lab the medicinal qualities of its venom have been known for some time. The protein agkisacutalin, found in the viper’s venom, is an effective anticoagulant, minimizing blood clots that cause stroke or heart failure with very few side effects. But the protein has not yet been isolated in a form safe enough for human consumption.

In the study, the researchers modified the genes of the yeast Pichia pastoris, often used as a model organism for genetic experiments (and also sometimes as a food additive). The researchers knocked out two of the yeast’s genes and replaced them with snake genes, then fed the yeast with glycerol at room temperature. After 18 hours, they added methanol, which converted the glycerol to the anticoagulant proteins found in the snake venom.

So far the yeast has passed biosafety checks in China where it was developed. Though this venom-based anticoagulant isn’t available yet, the researchers hope it will be soon; they have partnered with a private biomedical company to scale up the production of the anticoagulant so they can bring it to market, the South China Morning Post reports—the yeast tends to die after producing the protein for 38 hours. But if they are able to iron out the wrinkles of the large-scale yeast production process, the researchers could create as much of the protein each year as would otherwise be made by killing 15,000 snakes.