title: Why are diphenylalanine-based peptide nanostructures so rigid? Insights from first principles calculations.
abstract: The diphenylalanine peptide self-assembles to form nanotubular structures of remarkable mechanical, piezolelectrical, electrical, and optical properties. The tubes are unexpectedly stiff, with reported Young's moduli of 19-27 GPa that were extracted using two independent techniques. Yet the physical basis for the remarkable rigidity is not fully understood. Here, we calculate the Young's modulus for bulk diphenylalanine peptide from first principles, using density functional theory with dispersive corrections. The calculation demonstrates that at least half of the stiffness of the material is the result of dispersive interactions. We further quantify the nature of various inter- and intramolecular interactions. We reveal that despite the porous nature of the lattice, there is an array of rigid nanotube backbones with interpenetrating "zipper-like" aromatic interlocks that result in stiffness and robustness. This presents a general strategy for the analysis of bioinspired functional materials and may pave the way for rational design of bionanomaterials.
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute of Science , Rehovoth 76100, Israel.
authors.forename: Ido
authors.initials: I
authors.lastname: Azuri
authors.forename: Lihi
authors.initials: L
authors.lastname: Adler-Abramovich
authors.forename: Ehud
authors.initials: E
authors.lastname: Gazit
authors.forename: Oded
authors.initials: O
authors.lastname: Hod
authors.forename: Leeor
authors.initials: L
authors.lastname: Kronik
mesh_terms: D004151:Dipeptides; D004548:Elasticity; D008958:Models, Molecular; D049329:Nanostructures / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry; D011487:Protein Conformation
chemical_list: D004151:Dipeptides; D010455:Peptides; C026650:phenylalanylphenylalanine; D010649:Phenylalanine