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Fremaux J.,University of Bordeaux Segalen | Fremaux J.,UREkA Sarl | Kauffmann B.,University of Bordeaux Segalen | Guichard G.,University of Bordeaux Segalen
Journal of Organic Chemistry | Year: 2014

The synthesis and conformational analysis of aliphatic oligoureas containing multiple adjacent N-alkylated units derived from proline (i.e., Prou) are reported. The insertion of trisubstituted ureas in the main chain of N,N′-linked oligourea foldamers locally impairs the characteristic three centered-hydrogen bonding pattern associated with the formation of 2.5-helical structures. Three series of oligomers have been studied: one series in which the Prou repeat is flanked on both sides by canonical urea residues (e.g., oligomers 2-6), one series with canonical residues on either side of the Prou repeat (oligomers 12 and 23), and one series consisting exclusively of Prou residues (oligomers 25 and 26). Spectroscopic (NMR and electronic circular dichroism) and X-ray diffraction studies reveal that the 2.5-helix formed by oligomers of N,N′-disubstituted ureas is robust enough to accommodate short oligopyrrolidine segments (Prou)n (n < 7) that alone display no intrinsic folding propensity. © 2014 American Chemical Society. Source


Collie G.W.,University of Bordeaux Segalen | Pulka-Ziach K.,French National Center for Scientific Research | Lombardo C.M.,University of Bordeaux Segalen | Fremaux J.,French Institute of Health and Medical Research | And 7 more authors.
Nature Chemistry | Year: 2015

The design and construction of biomimetic self-Assembling systems is a challenging yet potentially highly rewarding endeavour that contributes to the development of new biomaterials, catalysts, drug-delivery systems and tools for the manipulation of biological processes. Significant progress has been achieved by engineering self-Assembling DNA-, protein-And peptide-based building units. However, the design of entirely new, completely non-natural folded architectures that resemble biopolymers ( € foldamers €) and have the ability to self-Assemble into atomically precise nanostructures in aqueous conditions has proved exceptionally challenging. Here we report the modular design, formation and structural elucidation at the atomic level of a series of diverse quaternary arrangements formed by the self-Assembly of short amphiphilic α-helicomimetic foldamers that bear proteinaceous side chains. We show that the final quaternary assembly can be controlled at the sequence level, which permits the programmed formation of either discrete helical bundles that contain isolated cavities or pH-responsive water-filled channels with controllable pore diameters. © 2015 Macmillan Publishers Limited. All rights reserved. Source


Mauran L.,University of Bordeaux Segalen | Mauran L.,French National Center for Scientific Research | Mauran L.,UREkA Sarl | Kauffmann B.,University of Bordeaux Segalen | And 6 more authors.
Comptes Rendus Chimie | Year: 2016

Template-based stabilization of α-peptide helices with short accessory non-peptide helical foldamers fused either at the N- or C-terminus or at both ends of the peptide segment has been investigated by NMR spectroscopy in polar solvents and by X-ray diffraction. In this work, we focused on aliphatic N,N′-linked oligoureas that form predictable and well-defined helical structures akin to α-helices. Our results indicate that urea oligomers have the ability to enforce a peptide segment to adopt a well-defined α-helical structure and may suggest a general approach to stabilize short helical peptide epitopes for the development of modulators of protein-protein interactions. © 2015 Académie des sciences. Source


Fremaux J.,University of Bordeaux Segalen | Fremaux J.,French National Center for Scientific Research | Fremaux J.,UREkA Sarl | Mauran L.,University of Bordeaux Segalen | And 12 more authors.
Angewandte Chemie - International Edition | Year: 2015

Short α-peptides with less than 10 residues generally display a low propensity to nucleate stable helical conformations. While various strategies to stabilize peptide helices have been previously reported, the ability of non-peptide helical foldamers to stabilize α-helices when fused to short α-peptide segments has not been investigated. Towards this end, structural investigations into a series of chimeric oligomers obtained by joining aliphatic oligoureas to the C- or N-termini of α-peptides are described. All chimeras were found to be fully helical, with as few as 2 (or 3) urea units sufficient to propagate an α-helical conformation in the fused peptide segment. The remarkable compatibility of α-peptides with oligoureas described here, along with the simplicity of the approach, highlights the potential of interfacing natural and non-peptide backbones as a means to further control the behavior of α-peptides. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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