title: Hierarchical self-assembly of aminopyrazole peptides into nanorosettes in water.
abstract: Self-association of aminopyrazole peptide hybrid 1 leads to stacked nanorosettes. This remarkable, well-ordered structure obeys the laws of nucleic acid self-assembly. In a strictly hierarchical process, formation of aminopyrazole "base" triplets via a hydrogen bond network is accompanied by pi-stacking with a second rosette and final dimerization of two double rosettes to a four-layer superstructure, stabilized by a six-fold half-crown alkylammonium lock. The final complex is soluble in organic as well as in aqueous solution. It was characterized in the solid state by X-ray crystallography, in water by NMR spectroscopy, and in silico by quantum chemical shift calculation. All these methods provide strong evidence for the same hexameric complex geometry. Its structural features bear striking similarity to nucleic acid architectures and their peptidic counterparts, especially alanyl-PNA. The whole self-assembly process is highly solvent- and temperature-dependent and occurs with a high degree of cooperativity--no intermediates are observed. Formation and dissociation of the nanorosette, however, are kinetically slow. The limitation to a hexameric aggregate can be explained by six sterically demanding valine residues, whose replacement by alanines may result in formation of infinite fibers.
authors: Institute of Organic Chemistry, Universität Duisburg-Essen, Universitätsstrasse 5, 45117 Essen, Germany.
authors: Petra
authors: P
authors: Rzepecki
authors: Katrin
authors: K
authors: Hochdörffer
authors: Torsten
authors: T
authors: Schaller
authors: Jan
authors: J
authors: Zienau
authors: Klaus
authors: K
authors: Harms
authors: Christian
authors: C
authors: Ochsenfeld
authors: Xiulan
authors: X
authors: Xie
authors: Thomas
authors: T
authors: Schrader
mesh_terms: D018360:Crystallography, X-Ray; D049329:Nanostructures / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000737:chemistry*; D011720:Pyrazoles / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D010455:Peptides; D011720:Pyrazoles; D014867:Water