Structural similarity between β3-peptides synthesized from β3-homo-amino acids and aspartic acid monomers.

ABSTRACT Formation of stable secondary structures by oligomers that mimic natural peptides is a key asset for enhanced biological response. Here we show that oligomeric β³-hexapeptides synthesized from l-aspartic acid monomers (β³-peptides 1, 5a, and 6) or homologated β³-amino acids (β³-peptide 2), fold into similar stable 14-helical secondary structures in solution, except that the former form right-handed 14-helix and the later form left-handed 14-helix. β³-Peptides from l-Asp monomers contain an additional amide bond in the side chains that provides opportunities for more hydrogen bonding. However, based on the NMR solution structures, we found that β³-peptide from l-Asp monomers ( 1) and from homologated amino acids ( 2) form similar structures with no additional side-chain interactions. These results suggest that the β³-peptides derived from l-Asp are promising peptide-mimetics that can be readily synthesized using l-Asp monomers as well as the right-handed 14-helical conformation of these β³-peptides (such as 1 and 6) may prove beneficial in the design of mimics for right-handed α-helix of α-peptides. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 359-367, 2014. [ABSTRACT FROM AUTHOR]