title: Intrinsic Folding Proclivities in Cyclic β-Peptide Building Blocks: Configuration and Heteroatom Effects Analyzed by Conformer-Selective Spectroscopy and Quantum Chemistry.
abstract: This work describes the use of conformer-selective laser spectroscopy following supersonic expansion to probe the local folding proclivities of four-membered ring cyclic β-amino acid building blocks. Emphasis is placed on stereochemical effects as well as on the structural changes induced by the replacement of a carbon atom of the cycle by a nitrogen atom. The amide A IR spectra are obtained and interpreted with the help of quantum chemistry structure calculations. Results provide evidence that the building block with a trans-substituted cyclobutane ring has a predilection to form strong C8 hydrogen bonds. Nitrogen-atom substitution in the ring induces the formation of the hydrazino turn, with a related but distinct hydrogen-bonding network: the structure is best viewed as a bifurcated C8/C5 bond with the N heteroatom lone electron pair playing a significant acceptor role, which supports recent observations on the hydrazino turn structure in solution. Surprisingly, this study shows that the cis-substituted cyclobutane ring derivative also gives rise predominantly to a C8 hydrogen bond, although weaker than in the two former cases, a feature that is not often encountered for this building block.
authors.affiliation: CEA, Laboratoire Interactions Dynamique et Lasers (LIDyL), Bât. 522, 91191 Gif-sur-Yvette (France).|CNRS, Laboratoire Francis Perrin URA 2453, 91191 Gif-sur-Yvette (France).|Current address: Department of Chemistry, University of Dhaka, Dhaka-1000 (Bangladesh).
authors.forename: Mohammad
authors.initials: M
authors.lastname: Alauddin
authors.affiliation: CEA, Laboratoire Interactions Dynamique et Lasers (LIDyL), Bât. 522, 91191 Gif-sur-Yvette (France).|CNRS, Laboratoire Francis Perrin URA 2453, 91191 Gif-sur-Yvette (France).
authors.forename: Eric
authors.initials: E
authors.lastname: Gloaguen
authors.affiliation: CEA, Laboratoire Interactions Dynamique et Lasers (LIDyL), Bât. 522, 91191 Gif-sur-Yvette (France).|CNRS, Laboratoire Francis Perrin URA 2453, 91191 Gif-sur-Yvette (France).
authors.forename: Valérie
authors.initials: V
authors.lastname: Brenner
authors.affiliation: CEA, Laboratoire Interactions Dynamique et Lasers (LIDyL), Bât. 522, 91191 Gif-sur-Yvette (France).|CNRS, Laboratoire Francis Perrin URA 2453, 91191 Gif-sur-Yvette (France).
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tardivel
authors.affiliation: CEA, Laboratoire Interactions Dynamique et Lasers (LIDyL), Bât. 522, 91191 Gif-sur-Yvette (France). michel.mons@cea.fr.|CNRS, Laboratoire Francis Perrin URA 2453, 91191 Gif-sur-Yvette (France). michel.mons@cea.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Mons
authors.affiliation: CNRS, ISMO, Bât. 210, Université Paris Sud, UMR 8214, 91405 Orsay (France).
authors.forename: Anne
authors.initials: A
authors.lastname: Zehnacker-Rentien
authors.affiliation: CP3A Organic Synthesis Group, ICMMO, UMR 8182, Université Paris Sud, Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex (France).
authors.forename: Valérie
authors.initials: V
authors.lastname: Declerck
authors.affiliation: CP3A Organic Synthesis Group, ICMMO, UMR 8182, Université Paris Sud, Bât. 420, 15 rue Georges Clemenceau, 91405 Orsay cedex (France). david.aitken@u-psud.fr.
authors.forename: David J
authors.initials: DJ
authors.lastname: Aitken
mesh_terms: D000577:Amides / Q000737:chemistry*; D003503:Cyclobutanes / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared / Q000379:methods*
chemical_list: D000577:Amides; D003503:Cyclobutanes; D010456:Peptides, Cyclic
keywords: amino acids; conformation analysis; hydrazino turns; hydrogen bonds; laser spectroscopy