Mussels use chemical primer to cement themselves to rocks

Clinging to rocky shorelines and creaky piers, mussels showcase an enviable superpower:  cementing themselves to wet, slippery surfaces. Until now, researchers didn’t know how the mussels’ glue might work in salty seawater.

To solve the puzzle, scientists at the University of California, Santa Barbara turned to a molecule from microbes. The molecule has two striking similarities to proteins that make mussels stick. Both contain molecular fragments called catechol in close proximity to an amino acid called lysine. By tweaking the microbial compound, the researchers figured out what probably makes the mussel’s protein grip.

Catechol, a simple ringed molecule, forms sticky bonds with negatively charged surfaces — an early step in mussels’ cementing process. But surfaces under ocean water can have a thin layer of positively charged ions, which would block catechol binding. By modifying the microbial compound’s lysine, which also is positively charged, the researchers found that the amino acid works like a paint primer to prepare the surface. It uses its own positive charge to elbow out other positive ions on the surface, clearing the way for adhesion.

The finding may help steer researchers toward more seaworthy glues.