Purification, cDNA clone and recombinant expression of foot protein-3 from Mytilus coruscus

Mussels Mytilus coruscus can adhere to various solid surface in the presence of moisture. Mussel foot protein-3 (mfp-3) has been suggested as the main adhesive protein in the plaques closest to the adhesion interface and been the focus of substantial biomaterials development research within the last decade. The byssal plaques of M. coruscus were accumulated and variants of a family known as mcofp3 (Mytilus coruscus foot protein 3) were purified from acetic acid/urea extracts of plaques, with their N-terminal sequences determined thereafter. The cDNA sequence coding for the mcofp3 precursor was obtained from M. coruscus foot cDNA library. These precursors contain a putative signal peptide of 24 residues, a mature peptide sequence of 41-56 amino acids rich in Tyr, Gly, Pro, and Asn. The recombinant mcofp3 fused with a hexa-histidine affinity ligand was successfully expressed through an Escherichia coli expression system, and the recombinant mcofp3 was purified using affinity chromatography followed by reverse phase high performance liquid chromatography (HPLC). The DOPA content and adhesive properties of purified recombinant mcofp3 with or without tyrosinase modification were compared with the native mcofp3. These assays showed that recombinant mcofp3 has significant adhesive ability and may be useful as a bioadhesive in medical or underwater environments.