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Mytilus edulis foot protein-5 (Mefp-5) is an adhesive protein found in the adhesive plaque of the byssal thread of the common blue mussel, Mytilus edulis (L). While to date there have been eight proteins isolated from the byssal structure, this protein contains the greatest amount (27 mol %) of a unique amino acid, L-3,4-dihydroxyphenylalanine (L-Dopa), which is a posttranslational modification of the amino acid L-tyrosine. This protein has been shown to confer significant corrosion inhibition to a high strength, low alloy steel (HY80) when adsorbed onto the metal surface and the steel subsequently exposed to accelerated corrosion environments. To characterize how Mefp-5 interacts with the HY80 steel and thus provide corrosion inhibition, a variety of analytical techniques were implemented. Energy dispersive spectroscopy (EDS) was performed using a scanning electron microscope (SEM) on HY80 steel with three different treatments of Mefp-5 dissolved in deionized water, 0.05 M potassium phosphate buffer with a pH of 5.5, and the same buffer containing mushroom tyrosinase to facilitate the oxidation of the L-Dopa and subsequent intramolecular cross-linking. Fourier transform infrared spectroscopy (FT-IR) and Nanoscale infrared spectroscopy (Nano-IR) were performed on both a HY80 steel coupon and a glass slide containing Mefp-5 dissolved in deionized water. The results indicate that the amino acid L-Dopa in the Mefp-5 protein is intimately involved in the adsorption of the protein onto the two substrates tested. The SEM-EDS data indicate that the Mefp-5 adheres mostly through auto-oxidation and cross-linking, but when dissolved in buffer or buffer with enzyme, the protein interacts with the HY80 surface via a mixture of enzyme and metal mediated cross-linking and complexation, respectively. FT-IR and Nano-IR data for Mefp-5 adsorbed onto HY80 and glass steel exhibits similar results suggesting that the Mefp-5 adsorbed on the HY80 involves metal ion complexation by L-Dopa at the protein-metal interface.
Douglas C Hansen
Primary Advisor's Department
RI-NS-Matl Degrad&Electrochem Eng
Stander Symposium poster
Bennett, Brooke N., "Characterizing the Interaction of Mytilus edulis Foot Protein-5 with HY80 Steel" (2016). Stander Symposium Posters. 810.