New research breaks down the complex structure of snail mucus and identifies novel proteins.

Snail mucus is widely used in cosmetics, moisturizers, anti-aging creams, wound care treatments, and antimicrobials, but what is it, really?

This was the question posed by researchers in a new study that examines the molecular composition of snail mucus. When analyzing the mucus of a common garden snail, they found it contained a complex collection of proteins, some identified as entirely novel.

In the newly published paper in Nature Communications, scientists profile the mucus of Cornu aspersum — a species used in beauty product formulation and eaten as escargot — and detail the composition of three unique types of secretions —one that hydrates and protects its skin, another that works as a glue-like adhesive, and another that lubricates to allow the animal to move freely across surfaces.

“We were surprised that the mucus compositions were quite different, despite being produced by the same species,” says lead author Antonio Cerullo, a biochemistry Ph.D. student at the CUNY Graduate Center, in a news release.  “Even more so, the adhesive snail glue and the lubricious snail trail, which have completely opposite purposes, come from the same part of the snail. It was exciting to discover that very subtle differences in mucus compositions have huge impacts on their biological and material properties.”

The researchers say the hydrogels contain ions, sugars, and more than 70 proteins, including enzymes, mucins, lectins, and matrix proteins. About one-third of the proteins found in the mucus shared no similarity with any proteins in the global databases that were searched.

There are still many open questions about the macromolecular structure of mucus. Even human mucus, which has been studied much more extensively than snail mucus, is not well understood.

“Everyone is fascinated and disgusted by mucus. However, most people don’t realize just how complex and elegant these secretions are,” adds the study’s principal investigator Adam Braunschweig, who is a faculty member with the Nanoscience Initiative at the Advanced Science Research Center at the CUNY Graduate Center (CUNY ASRC) and a professor of chemistry and biochemistry at the Graduate Center and Hunter College.

The data revealed subtle differences that accounted for vast differences in properties of the mucus. One example involves the use of calcium. Calcium holds mucus networks together and solidifies the network. As a result, lubricating mucus has the least amount of calcium and the highest amount of calcium-binding proteins, while binding mucus has the opposite composition.

Snail mucus is currently being studied for applications in biomedicine, including surgical glues, as lubricants for eyes, joints, and medical implants, as well as drug delivery systems. More uses of snail mucus are being discovered every day, Braunschweig says.

CAPTION: A dendrogram (tree) showing the genetic similarity between 71 proteins against ~180 related proteins that were found previously in other mollusks. The results confirm that even when compared against hundreds of other proteins simultaneously, similar proteins still cluster together. The black bracket on the right signifies the “outgroup,” a group of proteins that is intentionally unrelated from the rest.

CREDIT: Antonio Cerullo