Constrained beta-amino acid-containing miniproteins

The construction of β-amino acid-containing peptides that fold to tertiary structures in solution remains challenging. Two model miniproteins, namely, Trp-cage and FSD, were scanned using a constrained β-amino acid in order to evaluate its impact on the folding process. Relationships between forces stabilizing the miniprotein structure and conformational stability of analogues were found. The possibility of a significant increase of the conformational stability of the studied miniproteins by substitution with the β-amino acid at the terminus of a helix is shown. On the basis of these results, β-amino acid containing-peptide analogs with helical fragments substantially altered by the incorporation of several constrained β-amino acids were designed, synthesized and evaluated with respect to their structure and stability. The smallest known β-amino acid-containing peptide with a well-defined tertiary structure is described.