Fine Tuning of β-Peptide Foldamers: a Single Atom Replacement Holds Back the Switch from an 8-Helix to a 12-Helix.
Cyclic homologated amino acids are important building blocks for the construction of helical foldamers. N-aminoazetidine-2-carboxylic acid (AAzC), an aza analogue of trans-2-aminocyclobutanecarboxylic acid (tACBC), displays a strong hydrazino turn conformational feature, which is proposed to act as an 8-helix primer. tACBC oligomers bearing a single N-terminal AAzC residue were studied to evaluate the ability of AAzC to induce and support an 8-helix along the oligopeptide length. While tACBC homooligomers assume a dominant 12-helix conformation, the aza-primed oligomers preferentially adopt a stabilized 8-helix conformation for an oligomer length up to 6 residues. The (formal) single-atom exchange at the N terminus of a tACBC oligomer thus contributes to the sustainability of the 8-helix, which resists the switch to a 12-helix. This effect illustrates atomic-level programmable design for fine tuning of peptide foldamer architectures.
['Altmayer-Henzien|Amandine|A|', 'Declerck|Valérie|V|', 'Farjon|Jonathan|J|', 'Merlet|Denis|D|', 'Guillot|Régis|R|', 'Aitken|David J|DJ|']
D002942:Circular Dichroism D010455:Peptides D011487:Protein Conformation D013055:Spectrophotometry, Infrared
foldamers hydrazino turn peptides helical structures hydrogen bonds