The 11/9-helix is one of nontraditional helices available to α/β-peptides with alternating residue types. Several β-amino acid residues are known to promote 11/9-helical folding with two types of intramolecular hydrogen bonds. Both β2-amino acids and β3-amino acids are common acyclic β-amino acids that can be regarded as homologs of α-amino acids with the same side chain group. However, β2-amimo acids have not been widely used as much as β3-amino acids partly because β2-residue is believed to be not as strong as β3-residue in promoting a distinct conformation. Here we report 11/9-helical folding of α/β-peptides that consist of L-α-alanine and (S)-β2-homoalanine with residue alternation. In addition, circular dichroism study reveals that β2-homoalanine promotes 11/9-helical folding more strongly than β3-homoalanine in polar protic solvent conditions.
Bibliographical noteFunding Information:
National Research Foundation of Korea, Grant/Award Numbers: NRF‐2021R1A2C1013477, NRF‐2020R1F1A1075279 Funding information
This study was supported by the National Research Foundation of Korea (NRF‐2020R1F1A1075279, NRF‐2021R1A2C1013477). High‐field NMR data were acquired at the Korea Basic Science Institute (Western Seoul).
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All Science Journal Classification (ASJC) codes
- Organic Chemistry