I suspect that it cross-links the other proteins, creating a stiffer gel. In related work, I am trying to determine the structure of the mucus gel. Like all mucus secretions, it is a network of tangled polymers holding a large volume of water in place. Typically more than ninety percent of the volume of any mucus gel is water. The polymers that make up limpet mucus, however, are quite different from those in mammalian mucus.
Mammalian mucus is made of the giant glycoprotein mucin.
Limpet mucus, on the other hand, is made primarily of a collection of non-glycosylated, acidic proteins between 20 and 230 kD. It is much more viscous and stiffer than mammalian mucus, and less soluble. Thus, it will interesting to determine how it is put together. In addition to understanding the biochemistry of limpet pedal mucus, I would like to know more about its secretion. I have recently determined which cells in the limpets' feet secrete the 118 kD protein. For this project, I made an antibody against the protein.