title: Fine Tuning of β-Peptide Foldamers: a Single Atom Replacement Holds Back the Switch from an 8-Helix to a 12-Helix.
abstract: 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.
authors.affiliation: CP3A Organic Synthesis Group, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France).
authors.forename: Amandine
authors.initials: A
authors.lastname: Altmayer-Henzien
authors.affiliation: CP3A Organic Synthesis Group, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France).
authors.forename: Valérie
authors.initials: V
authors.lastname: Declerck
authors.affiliation: LRMN, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France).
authors.forename: Jonathan
authors.initials: J
authors.lastname: Farjon
authors.affiliation: LRMN, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France).
authors.forename: Denis
authors.initials: D
authors.lastname: Merlet
authors.affiliation: Services Communs, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France).
authors.forename: Régis
authors.initials: R
authors.lastname: Guillot
authors.affiliation: CP3A Organic Synthesis Group, ICMMO UMR 8182, Université Paris Sud, 15 Rue George Clemenceau, 91405 Orsay cedex (France). david.aitken@u-psud.fr.
authors.forename: David J
authors.initials: DJ
authors.lastname: Aitken
mesh_terms: D002942:Circular Dichroism; D010455:Peptides / Q000737:chemistry*; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
chemical_list: D010455:Peptides
keywords: foldamers; helical structures; hydrazino turn; hydrogen bonds; peptides