3,4-Dihydroxyphenylalanine (Dopa), which is a hydroxylated form of the tyrosine residue, has been suggested to be a key factor for rapid and strong underwater adhesion. Mussel adhesive proteins (MAPs) are one of examples where Dopa chemistry is the core of their underwater adhesion with extremely high Dopa contents of ~10-25 mol%. The biosynthesis of recombinant MAPs in an Escherichia coli system was a good approach to overcome the availability limitation that results from the extremely low yield of natural extraction of MAPs from mussel feet and to apply MAPs as a universal underwater bioglue. However, Dopa incorporation always follows as the biggest problem because lack of Dopa in recombinant MAPs critically limited the underwater adhesion. Here, we explore the in vivo residue-specific incorporation of Dopa into recombinant MAPs, allowing the quantitative replacement of tyrosine residues by Dopa with a yield of over ~90 %, to create, for the first time, engineered MAPs in E. coli with a very high Dopa content close to that of natural MAPs. Using several analyses, we confirmed that Dopa-incorporated engineered recombinant MAPs exhibited the superior surface adhesion and water-resistance abilities by assistance of Dopa-mediated interactions including oxidative Dopa cross-linking. In addition, their underwater adhesive properties were comparable to those of natural MAPs. Our results show their great potential as bioglues for use in practical underwater applications.

Bioglue for wet condition; dopa incorporated engineered mussel adhesive proteins

251st National Meeting (2016)

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