title: α,β-Dehydro-Dopa: A Hidden Participant in Mussel Adhesion.
abstract: Dopa (l-3,4-dihydroxyphenylalanine) is a key chemical signature of mussel adhesive proteins, but its susceptibility to oxidation has limited mechanistic investigations as well as practical translation to wet adhesion technology. To investigate peptidyl-Dopa oxidation, the highly diverse chemical environment of Dopa in mussel adhesive proteins was simplified to a peptidyl-Dopa analogue, N-acetyl-Dopa ethyl ester. On the basis of cyclic voltammetry and UV-vis spectroscopy, the Dopa oxidation product at neutral to alkaline pH was shown to be α,β-dehydro-Dopa (ΔD), a vinylcatecholic tautomer of Dopa-quinone. ΔD exhibited an adsorption capacity on TiO2 20-fold higher than that of the Dopa homologue in the quartz crystal microbalance. Cyclic voltammetry confirmed the spontaneity of ΔD formation in mussel foot protein 3F at neutral pH that is coupled to a change in protein secondary structure from random coil to β-sheet. A more complete characterization of ΔD reactivity adds a significant new perspective to mussel adhesive chemistry and the design of synthetic bioinspired adhesives.
authors.affiliation: Marine Science Institute, University of California , Santa Barbara, California 93106, United States.
authors.forename: Razieh
authors.initials: R
authors.lastname: Mirshafian
authors.affiliation: Marine Science Institute, University of California , Santa Barbara, California 93106, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: Department of Chemical Engineering, University of California , Santa Barbara, California 93106, United States.
authors.forename: Jacob N
authors.initials: JN
authors.lastname: Israelachvili
authors.affiliation: Marine Science Institute, University of California , Santa Barbara, California 93106, United States.|Department of Molecular, Cell & Developmental Biology, University of California , Santa Barbara, California 93106, United States.
authors.forename: J Herbert
authors.initials: JH
authors.lastname: Waite
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000502:physiology*; D002851:Chromatography, High Pressure Liquid; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives* / Q000502:physiology; D010084:Oxidation-Reduction; D058105:Polymerization; D011506:Proteins / Q000502:physiology; D058525:Quartz Crystal Microbalance Techniques; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D011506:Proteins; C037403:adhesive protein, mussel; D004295:Dihydroxyphenylalanine