Boronate complex formation with Dopa containing mussel adhesive protein retards ph-induced oxidation and enables adhesion to mica.

TitleBoronate complex formation with Dopa containing mussel adhesive protein retards ph-induced oxidation and enables adhesion to mica.
Publication TypeJournal Article
Year of Publication2014
AuthorsKan, Y, Danner, EW, Israelachvili, JN, Chen, Y, Waite, JH
JournalPLoS One
Volume9
Issue10
Paginatione108869
Date Published2014
ISSN1932-6203
KeywordsAdhesives, Aluminum Silicates, Animals, Boronic Acids, Dihydroxyphenylalanine, Mollusca, Proteins
Abstract

The biochemistry of mussel adhesion has inspired the design of surface primers, adhesives, coatings and gels for technological applications. These mussel-inspired systems often focus on incorporating the amino acid 3,4-dihydroxyphenyl-L-alanine (Dopa) or a catecholic analog into a polymer. Unfortunately, effective use of Dopa is compromised by its susceptibility to auto-oxidation at neutral pH. Oxidation can lead to loss of adhesive function and undesired covalent cross-linking. Mussel foot protein 5 (Mfp-5), which contains ∼ 30 mole % Dopa, is a superb adhesive under reducing conditions but becomes nonadhesive after pH-induced oxidation. Here we report that the bidentate complexation of borate by Dopa to form a catecholato-boronate can be exploited to retard oxidation. Although exposure of Mfp-5 to neutral pH typically oxidizes Dopa, resulting in a>95% decrease in adhesion, inclusion of borate retards oxidation at the same pH. Remarkably, this Dopa-boronate complex dissociates upon contact with mica to allow for a reversible Dopa-mediated adhesion. The borate protection strategy allows for Dopa redox stability and maintained adhesive function in an otherwise oxidizing environment.

DOI10.1371/journal.pone.0108869
Alternate JournalPLoS ONE
PubMed ID25303409
PubMed Central IDPMC4193769
Grant ListR01 DE018468 / DE / NIDCR NIH HHS / United States
R01 DE018468 / DE / NIDCR NIH HHS / United States