Stereochemical Effects on the Self-Assembly of Pyrenylalanine-Phenylalanine Dipeptide

Abstract

Abstract The design and control of self-assembling biomaterials have significantly attracted attention over the last decades because of their broad ranges of applications. Here, we introduce the self-assembled fibers of the pyrene connected dipeptides, l-pyrenylalanine-l-phenylalanine (l-Pyr-l-Phe) and d-pyrenylalanine-l-phenylalanine (d-Pyr-l-Phe), and their structural analysis using experimental and computational techniques. While l-Pyr-l-Phe self-assembled into solid fibers, d-Pyr-l-Phe self-assembled into hydrogels with different morphologies. Fluorescence spectroscopy revealed monomer and red-shifted excimer emissions of the self-assembled l-Pyr-l-Phe and d-Pyr-l-Phe dipeptide nanostructures, respectively. This result was related to different 13C and 15N solid-state nuclear magnetic resonance (NMR) data on the backbone and side-chains of the self-assembled dipeptides. Molecular dynamics simulations demonstrated detailed information about the chirality effects of the dipeptides on their self-assembled structures.