title: Psi[CH(CF(3))NH]Gly-peptides: synthesis and conformation analysis.
abstract: Psi[CH(CF(3))NH]Gly peptides, a conceptually new class of peptidomimetics having a stereogenic trifluoroethylamine group as a natural peptide-bond surrogate, have been synthesized by stereoselective addition of alpha-amino acid esters to trans-3,3,3-trifluoro-1-nitropropene. Long range nuclear Overhauser effects, detected via ROESY experiments, provided evidence that model Psi[CH(CF(3))NH]Gly-tetrapeptides incorporating a trifluoroethylamine mimic of the dipeptide loop Pro-Gly can be represented by an ensemble of unfolded and folded conformations. The latter are driven by the formation of a hydrogen bond between a carbonyl group and the aminic proton of the trifluoroethylamine unit. MD calculations indicate a population of conformers which adopt folded beta turn structures for all the L-peptides; on the other hand, a D-stereochemistry at the Pro residue induces a natural folding towards a beta hairpin conformation driven by the formation of a second hydrogen bond, regardless of the stereochemistry of the stereogenic peptide bond surrogate.
authors.affiliation: Dipartimento di Chimica, Materiali, e Ingegneria Chimica Giulio Natta, Politecnico di Milano, via Mancinelli 7, 20131, Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Molteni
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Bellucci
authors.forename: Serena
authors.initials: S
authors.lastname: Bigotti
authors.forename: Stefania
authors.initials: S
authors.lastname: Mazzini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Volonterio
authors.forename: Matteo
authors.initials: M
authors.lastname: Zanda
mesh_terms: D032701:Biomimetics; D003198:Computer Simulation; D005021:Ethylamines / Q000138:chemical synthesis / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D013237:Stereoisomerism
chemical_list: D005021:Ethylamines; D010455:Peptides; C032626:trifluoroethylamine