title: A Capped Dipeptide Which Simultaneously Exhibits Gelation and Crystallization Behavior.
abstract: Short peptides capped at their N-terminus are often highly efficient gelators, yet notoriously difficult to crystallize. This is due to strong unidirectional interactions within fibers, resulting in structure propagation only along one direction. Here, we synthesize the N-capped dipeptide, benzimidazole-diphenylalanine, which forms both hydrogels and single crystals. Even more remarkably, we show using atomic force microscopy the coexistence of these two distinct phases. We then use powder X-ray diffraction to investigate whether the single crystal structure can be extrapolated to the molecular arrangement within the hydrogel. The results suggest parallel β-sheet arrangement as the dominant structural motif, challenging existing models for gelation of short peptides, and providing new directions for the future rational design of short peptide gelators.
authors.affiliation: School of Chemistry, ‡The Australian Centre for Nanomedicine and the ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, and §Mark Wainwright Analytical Centre, The University of New South Wales , Sydney, 2052 NSW, Australia.
authors.forename: Adam D
authors.initials: AD
authors.lastname: Martin
authors.affiliation: School of Chemistry, ‡The Australian Centre for Nanomedicine and the ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, and §Mark Wainwright Analytical Centre, The University of New South Wales , Sydney, 2052 NSW, Australia.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Wojciechowski
authors.affiliation: School of Chemistry, ‡The Australian Centre for Nanomedicine and the ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, and §Mark Wainwright Analytical Centre, The University of New South Wales , Sydney, 2052 NSW, Australia.
authors.forename: Mohan M
authors.initials: MM
authors.lastname: Bhadbhade
authors.affiliation: School of Chemistry, ‡The Australian Centre for Nanomedicine and the ARC Centre of Excellence for Convergent Bio-Nano Science and Technology, and §Mark Wainwright Analytical Centre, The University of New South Wales , Sydney, 2052 NSW, Australia.
authors.forename: Pall
authors.initials: P
authors.lastname: Thordarson
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D003460:Crystallization; D004151:Dipeptides / Q000138:chemical synthesis / Q000737:chemistry*; D020100:Hydrogels / Q000737:chemistry*; D008956:Models, Chemical; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D001562:Benzimidazoles; D004151:Dipeptides; D020100:Hydrogels; C026650:phenylalanylphenylalanine; D010649:Phenylalanine; C031000:benzimidazole