Work

Unfolding a molecular trefoil derived from a zwitterionic metallopeptide to form self-assembled nanostructures

Year: 2015

Type: article

Abstract: While used extensively by nature to control the geometry of protein structures, and dynamics of proteins, such as self-organization, hydration forces and ionic interactions received less attention for controlling the behaviour of small molecules. Here we describe the synthesis and characterization of a novel zwitterionic metallopeptide consisting of a cationic core and three distal anionic groups linked by self-assembling peptide motifs. 2D NMR spectra, total correlated spectroscopy and nuclear Overhauser effect spectroscopy, show that the molecule exhibits a three-fold rotational symmetry and adopts a folded conformation in dimethyl sulfoxide due to Coulombic forces. When hydrated in water, the molecule unfolds to act as a self-assembling building block of supramolecular nanostructures. By combining ionic interactions with the unique geometry from metal complex and hydrophobic interactions from simple peptides, we demonstrate a new and effective way to design molecules for smart materials through mimicking a sophisticated biofunctional system using a conformational switch. Molecular self-assembly can be influenced by a number of external factors, though solvent effects are less commonly explored. Here, the authors present a three-armed metallopeptide complex that has a folded monomeric conformation in organic solvent, but can self-assemble in water into a supramolecular gel.

Source: Nature Communications

DOI: 10.1038/ncomms7165