title: Unprecedented chain-length-dependent conformational conversion between 11/9 and 18/16 helix in α/β-hybrid peptides.
abstract: α,β-Hybrid oligomers of varying lengths with alternating proteogenic α-amino acid and the rigid β(2,3,3) -trisubstituted bicyclic amino acid ABOC residues were studied using both X-ray crystal and NMR solution structures. While only an 11/9 helix was obtained in the solid state regardless of the length of the oligomers, conformational polymorphism as a chain-length-dependent phenomenon was observed in solution. Consistent with DFT calculations, we established that short oligomers adopted an 11/9 helix, whereas an 18/16 helix was favored for longer oligomers in solution. A rapid interconversion between the 11/9 helix and the 18/16 helix occurred for oligomers of intermediate length.
authors.affiliation: IBMM, UMR 5247 CNRS, Universités Montpellier 1 et 2, 15 avenue Charles Flahault, 34000 Montpellier (France) http://www.ibmm.univ-montp1.fr.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Legrand
authors.forename: Christophe
authors.initials: C
authors.lastname: André
authors.forename: Laure
authors.initials: L
authors.lastname: Moulat
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Wenger
authors.forename: Claude
authors.initials: C
authors.lastname: Didierjean
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Aubert
authors.forename: Marie Christine
authors.initials: MC
authors.lastname: Averlant-Petit
authors.forename: Jean
authors.initials: J
authors.lastname: Martinez
authors.forename: Monique
authors.initials: M
authors.lastname: Calmes
authors.forename: Muriel
authors.initials: M
authors.lastname: Amblard
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary
chemical_list: D010455:Peptides
keywords: 11/9 helix; 18/16 helix; bicyclic β-amino acid; foldamers; α,β-hybrid peptides