title: Folding control in cyclic peptides through N-methylation pattern selection: formation of antiparallel beta-sheet dimers, double reverse turns and supramolecular helices by 3alpha,gamma cyclic peptides.
abstract: Peptide foldamers constitute a growing class of nanomaterials with potential applications in a wide variety of chemical, medical and technological fields. Here we describe the preparation and structural characteristics of a new class of cyclic peptide foldamers (3alpha,gamma-CPs) that, depending on their backbone N-methylation patterns and the medium, can either remain as flat rings that dimerize through arrays of hydrogen bonds of antiparallel beta-sheet type, or can fold into twisted double reverse turns that, in the case of double gamma-turns, associate in nonpolar solvents to form helical supramolecular structures. A 3alpha,gamma-CP consists of a number of multiples of a repeat unit made up of four amino acid residues of alternating chirality: three corresponding to alpha-amino acids and one to a gamma-amino acid (a cis-3-aminocycloalkanecarboxylic acid).
authors.affiliation: Departamento de Química Orgánica, Laboratorios del CSIC, Facultad de Química, Universidad de Santiago, 15782 Santiago de Compostela, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Amorín
authors.forename: Luis
authors.initials: L
authors.lastname: Castedo
authors.forename: Juan R
authors.initials: JR
authors.lastname: Granja
mesh_terms: D018360:Crystallography, X-Ray; D019281:Dimerization; D006860:Hydrogen Bonding; D046911:Macromolecular Substances / Q000737:chemistry; D008745:Methylation; D008958:Models, Molecular; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary
chemical_list: D046911:Macromolecular Substances; D010456:Peptides, Cyclic