title: BIOLOGICAL ADHESIVES. Adaptive synergy between catechol and lysine promotes wet adhesion by surface salt displacement.
abstract: In physiological fluids and seawater, adhesion of synthetic polymers to solid surfaces is severely limited by high salt, pH, and hydration, yet these conditions have not deterred the evolution of effective adhesion by mussels. Mussel foot proteins provide insights about adhesive adaptations: Notably, the abundance and proximity of catecholic Dopa (3,4-dihydroxyphenylalanine) and lysine residues hint at a synergistic interplay in adhesion. Certain siderophores—bacterial iron chelators—consist of paired catechol and lysine functionalities, thereby providing a convenient experimental platform to explore molecular synergies in bioadhesion. These siderophores and synthetic analogs exhibit robust adhesion energies (E(ad) ≥-15 millijoules per square meter) to mica in saline pH 3.5 to 7.5 and resist oxidation. The adjacent catechol-lysine placement provides a "one-two punch," whereby lysine evicts hydrated cations from the mineral surface, allowing catechol binding to underlying oxides.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Greg P
authors.initials: GP
authors.lastname: Maier
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Rapp
authors.affiliation: Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93106, USA. herbert.waite@lifesci.ucsb.edu jacob@engineering.ucsb.edu butler@chem.ucsb.edu.
authors.forename: J Herbert
authors.initials: JH
authors.lastname: Waite
authors.affiliation: Department of Chemical Engineering, University of California, Santa Barbara, CA 93106, USA. Materials Department, University of California, Santa Barbara, CA 93106, USA. herbert.waite@lifesci.ucsb.edu jacob@engineering.ucsb.edu butler@chem.ucsb.edu.
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Israelachvili
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106, USA. herbert.waite@lifesci.ucsb.edu jacob@engineering.ucsb.edu butler@chem.ucsb.edu.
authors.forename: Alison
authors.initials: A
authors.lastname: Butler
mesh_terms: D000268:Adhesiveness; D000269:Adhesives / Q000737:chemistry*; D000538:Aluminum Silicates / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D004295:Dihydroxyphenylalanine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008239:Lysine / Q000737:chemistry*; D018716:Molecular Mimicry; D010084:Oxidation-Reduction; D011506:Proteins / Q000737:chemistry*; D017262:Siderophores / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry
chemical_list: D000269:Adhesives; D000538:Aluminum Silicates; D002396:Catechols; D011506:Proteins; D017262:Siderophores; C037403:adhesive protein, mussel; C009495:titanium dioxide; D004295:Dihydroxyphenylalanine; D014025:Titanium; D008239:Lysine; C034221:catechol; C011934:mica