Forget slow and steady. For the cone snail, it’s fast-acting chemistry that wins the race.Researchers have now shed light on the structure of a speedy insulin that cone snails use to paralyse prey.
You don’t want to mess with cone snails. These undersea predators stun prey with a harpoon-like appendage that injects venom, or they release immobilising venoms into nearby water. For decades scientists have been studying venoms, which are complex chemical brews. Venoms typically contain an array of molecules that act on the nervous system. In fact, one small protein from a cone snail’s venom has become Ziconotide, an FDA-approved medication for severe pain.
Our story begins last year when researchers noticed that the venom of the geographic cone snail, Conus geographus, contained something surprising — insulin.
We humans think of insulin as a life-saving medication for people with diabetes. However, insulin is a natural hormone that lowers our blood sugar, but people with diabetes can’t make it or don’t use it properly. In the snail, insulin can be subverted to quickly put prey in a coma by lowering its blood sugar, making it easier to capture.
There were two fascinating things about that snail venom insulin. First, it was incredibly fast acting. And second, it had evolved to be a weapon of chemical warfare. It was more similar to fish insulin or human insulin than to anything you’d expect in a snail.
The snail insulin isn’t quite as effective as human insulin, but the research team thinks snail insulin could make up for its low effectiveness with its high speed.