Evidence that the β-Peptide 14-Helix is Stabilized by β3-Residues with Side-Chain Branching Adjacent to the β-Carbon Atom

✍ Scribed by Tami L. Raguse; Jonathan R. Lai; Samuel H. Gellman

• Book ID: 102253483
• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: German
• Weight: 136 KB
• Volume: 85
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.200290001

✦ Synopsis

Abstract

Oligomers of β‐substituted β‐amino acids (‘β^3^‐peptides') are known to adopt a helical secondary structure defined by 14‐membered ring hydrogen bonds ('14‐helix'). Here, we describe a deca‐β^3^‐peptide, 1, that does not adopt the 14‐helical conformation and that may prefer an alternative secondary structure. β^3^‐Peptide 1 is composed exclusively of residues with side chains that are not branched adjacent to the β‐C‐atom (β^3^‐hLeu, β^3^‐hLys, and β^3^‐hTyr). In contrast, an analogous β‐peptide, 2, containing β^3^‐hVal residues in place of the β^3^‐hLeu residues of 1, adopts a 14‐helical conformation in MeOH, according to CD data. These results illustrate the importance of side‐chain branching in determining the conformational preferences of β^3^‐peptides.