Characterization of Molecular Interactions of Mytilus edulis Foot Proteins on Model Hydrated Surfaces

Abstract : The sea mussel Mytilus edulis adheres tenaciously to surfaces that exhibit a wide range of properties in seawater. A study was conducted to gain a better understanding of the interactions between two of the mussel foot proteins found in the adhesive plaque (Mefp-1 and Mefp-2) and several substrata with different surface properties (germanium, polystyrene and poly (octadecyl methacrylate). Mefp-1 excludes Mefp-2 from a germanium surface until the L-dopa residues of Mefp-1 are converted to the quinone form, suggesting that Mefp-1 is a hi-functional primer that requires activation by a catechol oxidase. However, Mefp-2 adsorbs to germanium, polystyrene and poly (octadecyl methacrylate) at least as strongly as Mefp-1,indicating that Mefp-1 does not possess unique properties that allows it to out-perform other mussel foot proteins in forming an adhesive bond with the substratum. We also tested the hypothesis that nucleophilic addition of the epsilon-amino groups of lysine residues into the oxidized catechol functionality (quinone) of the L-dopa residues in Mefp-1 is a cross-linking reaction in the plaque. Experimental results did not support this hypothesis. The plaque-forming reactions responsible for mussel adhesion to surfaces remain elusive.