Adaptive synergy between catechol and lysine promotes wet adhesion by surface salt displacement

Keeping it sticky when wet Some biological molecules are remarkably sticky, even to surfaces submerged in water. Mussel adhesion, for example, is based on the overproduction of dihydroxyphenylalanine (DOPA) and proteins with a high abundance of cationic amine residues such as lysine. Using bacterial iron chelators consisting of paired DOPA and lysine groups as analogs for the mussel proteins, Maier et al. show that these two functional groups synergistically enhance interfacial adhesion (see the Perspective by Wilker). The lysine appears to displace hydrated cations from the surface, thus giving a dry patch for better adhesion. Science , this issue p. 628 ; see also p. 582