title: Synthesis and conformational studies of peptido-squaramide foldable modules: a new class of turn-mimetic compounds.
abstract: The β-turn unit is one of the most important secondary structure elements in proteins. The access to new conformationally controlled foldable modules can afford compounds with interesting bioactivities. Here, we describe a new family of peptido-squaramide foldable modules based on the considerable potential of the squaramide unit as a hydrogen bond donor and acceptor as well as the low rotational barrier of the C-N bond. The conformational analysis by NMR of these modules in chloroform and acetonitrile solution shows that a disecondary squaramide with the 4-aminobutyric acid in one of its substituents can mimic the β-turn structure driven by the formation of an intramolecular hydrogen bonded ten-membered ring. This structure, although flexible, has been successfully combined with dipeptide chains to induce the formation of a hairpin-like structure driven by the formation of several cross-strand intramolecular hydrogen bonds.
authors.affiliation: Departament de Química, Universitat de les Illes Balears, Crta de Valldemosa km 7.5, Palma, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez
authors.forename: Angel
authors.initials: A
authors.lastname: Sampedro
authors.forename: Elena
authors.initials: E
authors.lastname: Sanna
authors.forename: Antoni
authors.initials: A
authors.lastname: Costa
authors.forename: Carmen
authors.initials: C
authors.lastname: Rotger
mesh_terms: D000577:Amides / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*
chemical_list: D000577:Amides; D010455:Peptides