Molecular design principles of Lysine-DOPA wet adhesion

Yiran Li,Yi Cao,Kelsey G Defrates,Phillip B Messersmith,Haoqi Wang,Jing Cheng,Severin J Sigg,Peyman Delparastan

doi:10.1038/s41467-020-17597-4

Abstract

The mussel byssus has long been a source of inspiration for the adhesion community. Recently, adhesive synergy between flanking lysine (Lys, K) and 3,4-Dihydroxyphenylalanine (DOPA, Y) residues in the mussel foot proteins (Mfps) has been highlighted. However, the complex topological relationship of DOPA and Lys as well as the interfacial adhesive roles of other amino acids have been understudied. Herein, we study adhesion of Lys and DOPA-containing peptides to organic and inorganic substrates using single-molecule force spectroscopy (SMFS). We show that a modest increase in peptide length, from KY to (KY)3, increases adhesion strength to TiO2. Surprisingly, further increase in peptide length offers no additional benefit. Additionally, comparison of adhesion of dipeptides containing Lys and either DOPA (KY) or phenylalanine (KF) shows that DOPA is stronger and more versatile. We furthermore demonstrate that incorporating a nonadhesive spacer between (KY) repeats can mimic the hidden length in the Mfp and act as an effective strategy to dissipate energy.

Highlights

The mussel byssus has long been a source of inspiration for the adhesion community
A unique feature of these interfacial proteins is the presence of large amounts of post-translationally modified amino acid 3,4-dihydroxyphenylalanine (DOPA), a catechol-containing residue that is believed to be a major contributor to wet adhesion[7,8,9,10,11]
single-molecule force spectroscopy (SMFS) studies further revealed that the average detaching force for DOPA and Lys dipeptide is ~300 pN on mica surface, which was observably higher than that of a dipeptide in which the Lys side chain was protected (~90 pN)[9,26]

Summary

Introduction

The mussel byssus has long been a source of inspiration for the adhesion community. Recently, adhesive synergy between flanking lysine (Lys, K) and 3,4-Dihydroxyphenylalanine (DOPA, Y) residues in the mussel foot proteins (Mfps) has been highlighted. We first measure the detaching force of DOPA-Lys peptides of various lengths (KY), (KY)[3], and (KY)[10] with TiO2. In ~2–5% of total force-extension (F–X) curves, single rupture force events were observed at ~20–60 nm, indicating the peptide surface detachment (Supplementary Fig. 9).

Results

Conclusion