New Helical Foldamers:Heterogeneous Backbones with 1:2 and 2:1 alpha:beta-Amino Acid Residue Patterns

摘要

Specific folding of protein backbones creates specific side-chain arrangements that lead to complex molecular activities.The relationship between biopolymer function and conformation has inspired many chemists to seek unnatural oligomers with strong folding propensities ("foldamers"),which provide a new basis for creating useful molecules.Foldamer design strategies that depart from the specific architectural features of proteins could be particularly valuable.One such strategy is the use of heterogeneous backbones,i.e.,backbones that contain subunits of different types.Several groups have recently shown that short oligomers with a 1:1 alternation of alpha- and beta-amino acid residues ("alpha/beta-peptides") can adopt helical conformations.Cyclic constraints within the beta-amino acid residues are essential for conformational stability in polar solvents,and the size of the constraining ring determines the type of helix formed.