Nanoribbons self-assembled from short peptides demonstrate the formation of polar zippers between \u03b2-sheets

Meng Wang,Henry Cox,Wei Yang,Yurong Zhao,Yawei Sun,Stephen M King,Thomas A Waigh,Jian Ren Lu,Sarah E Rogers,Dong Wang,Peng Zhou,Hai Xu,Zongyi Li,Jun Yang,Jing Deng,Jiqian Wang,Xuzhi Hu

doi:10.1038/s41467-018-07583-2

Abstract

Peptide self-assembly is a hierarchical process, often starting with the formation of α-helices, β-sheets or β-hairpins. However, how the secondary structures undergo further assembly to form higher-order architectures remains largely unexplored. The polar zipper originally proposed by Perutz is formed between neighboring β-strands of poly-glutamine via their side-chain hydrogen bonding and helps to stabilize the sheet. By rational design of short amphiphilic peptides and their self-assembly, here we demonstrate the formation of polar zippers between neighboring β-sheets rather than between β-strands within a sheet, which in turn intermesh the β-sheets into wide and flat ribbons. Such a super-secondary structural template based on well-defined hydrogen bonds could offer an agile route for the construction of distinctive nanostructures and nanomaterials beyond β-sheets.

Highlights

Peptide self-assembly is a hierarchical process, often starting with the formation of α-helices, β-sheets or β-hairpins
We demonstrate that insertion of an uncharged polar residue at the intramolecular hydrophobic/ hydrophilic interface can promote the formation of well-defined super-secondary structures based on side chain hydrogen bonding (H-bonding) interactions among β-sheets, which eventually lead to distinctive nanoribbons, whilst insertion of hydrophobic amino acid residues results only in amyloid-like nanofibrils
Given that charged Lys residues are mainly projected on their surfaces, our preliminary experiments have revealed, for example, that the Ac-I3norVGK-NH2 nanofibers readily template the synthesis of thin silica nanotubes, while the Ac-I3QGK-NH2 nanoribbons induced the formation of silica nanotapes under ambient aqueous conditions, as shown in Supplementary Figure 10

Summary

Introduction

Peptide self-assembly is a hierarchical process, often starting with the formation of α-helices, β-sheets or β-hairpins. By rational design of short amphiphilic peptides and their self-assembly, here we demonstrate the formation of polar zippers between neighboring β-sheets rather than between β-strands within a sheet, which in turn intermesh the β-sheets into wide and flat ribbons Such a super-secondary structural template based on well-defined hydrogen bonds could offer an agile route for the construction of distinctive nanostructures and nanomaterials beyond β-sheets. Upon insertion of a glutamine (Gln or Q) residue at the interface between the hydrophobic I3 motif and the hydrophilic lysine (Lys or K) residue, the resulting Ac-I3QGK-NH2 tends to form wide and flat ribbons[6] Because both short peptides adopt β-sheet conformations, the dramatic variation in self-assembled nanostructures might imply different modes of interactions of the β-sheets. There are usually errors associated with AFM height measurements, the bilayer thickness of Ac-I3QGK-NH2 was found to be mostly between 3.5 and 4.0 nm based on AFM sectional height profiling of ~30 individual ribbons (Supplementary Figure 1)

Methods

Results

Conclusion