Impact of substituent effects on the design of ß-sheet mimetics and ß-double helices from (E)-vinylogous γ-amino acid oligomers.

ABSTRACT

Here we report the design, single crystal conformations, impact of the substituents and structural differences of two structurally important motifs, ß-sheets and ß-double helices. Though ß-sheets are common structural motifs in protein structures, ß-double helices are not common in proteins and peptides. We found that both ß-sheet mimetics and ß-double helices can be constructed from the homooligomers of α,ß-unsaturated γ-amino acids. Results suggested that introducing gem-dialkyl substitutions at the γ-carbon of the homooligomer of α,ß-unsaturated γ-amino acids resulted in the ß-double helix conformation, while the same oligomer with monosubstitution at the γ-carbon displayed a ß-sheet structure.