title: Spontaneous Self-Assembly of Fully Protected Ester 1:1 [α/α-Nα-Bn-hydrazino] Pseudodipeptides into a Twisted Parallel β-Sheet in the Crystal State.
abstract: Previous studies have demonstrated that amidic α/β-pseudodipeptides, 1:1 [α/α-Nα-Bn-hydrazino], have the ability to fold via a succession of γ-turn (C7pseudocycle) and hydrazinoturn in CDCl3solution, their amide terminals enabling the formation of an intramolecular H-bond network. Despite their lack of a primary amide terminals allowing the formation of the hydrazinoturn, their ester counterparts 1-4 were proven to self-assemble into C6and C7pseudocycles by intramolecular H-bonds in solution state and into an uncommon twisted parallel β-sheet through intermolecular H-bonding in the crystal state to form a supramolecular helix, with eight molecules needed to complete a full 360° rotation. Such self-organization (with eight molecules) has only been observed in a specific α/α-pseudodipeptide, depsipeptide (Boc-Leu-Lac-OEt). Relying on IR absorption, NMR, X-ray diffraction, and CD analyses, the aim of this study was to demonstrate that stereoisomers of ester 1:1 [α/α-Nα-Bn-hydrazino] pseudodipeptides 1-4 are able to self-assemble into this β-helical structure. The absolute configuration of the asymmetric Cα-atom of the α-amino acid residue influences the left- or right-handed twist without changing the pitch of the formed helix.
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375 , 1 rue Grandville, BP 20451, 54001 Nancy cedex, France.
authors.forename: Eugénie
authors.initials: E
authors.lastname: Romero
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375 , 1 rue Grandville, BP 20451, 54001 Nancy cedex, France.
authors.forename: Ralph-Olivier
authors.initials: RO
authors.lastname: Moussodia
authors.affiliation: Ingénierie Moléculaire et Physiopathologie Articulaire (IMoPA), Université de Lorraine-CNRS, UMR 7365 and Service Commun de Biophysique Interactions Moléculaires (SCBIM), Université de Lorraine, FR3209, Biopôle de l'Université de Lorraine, Campus Biologie Santé - Faculté de Médecine , 9 Avenue de la Forêt de Haye, CS 50184, 54505 Vandœuvre-lès-Nancy, France.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Kriznik
authors.affiliation: Laboratoire de Crystallographie, Résonance Magnétique et Modélisations (CRM2), Université de Lorraine-CNRS, UMR 7036, Faculté des Sciences et Technologies , BP 70239, Boulevard des Aiguillettes, 54506 Vandœuvre-lès-Nancy cedex, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Wenger
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375 , 1 rue Grandville, BP 20451, 54001 Nancy cedex, France.
authors.forename: Samir
authors.initials: S
authors.lastname: Acherar
authors.affiliation: Laboratoire de Chimie Physique Macromoléculaire (LCPM), Université de Lorraine-CNRS, UMR 7375 , 1 rue Grandville, BP 20451, 54001 Nancy cedex, France.
authors.forename: Brigitte
authors.initials: B
authors.lastname: Jamart-Grégoire
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D004151:Dipeptides / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D006834:Hydrazines / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D004151:Dipeptides; D004952:Esters; D006834:Hydrazines