Peptide mimics of marine mussel adhesives

Marine organisms such as the common blue mussel ( Mytilus edulis) affix themselves to surfaces by producing a protein-based glue. The soluble precursor protein of this biomaterial contains high levels of the unusual amino acid 3,4-dihydroxyphenylalanine (DOPA) and cross-links into a hardened matrix for adhesion. Interesting properties of this adhesive include a transition metal (e.g., iron, zinc, copper, manganese) content more than 100,00 times that of the surrounding waters. To better understand the bonding interactions of these marine biomaterials, we are studying the roles of transition metals in biomaterial synthesis. Peptide mimics of marine mussel adhesives were prepared and reacted with various metal ions to produce soluble cross-linked model complexes suitable for spectroscopic characterization. A DOPA residue compatible with solid-phase peptide synthesis was developed for the preparation of DOPA-containing peptides. Ultraviolet-visible absorption spectroscopy for peptide complexes of Ti4+, VO2+, V3+, Mn3+, Fe3+, Co2+ , Ni2+, and Cu2+ was used to identify potential cross-linking modes. These spectra of the metal-peptide complexes were compared to analogous compounds of catechol and tiron