title: Spectroscopic evidence for the formation of helical structures in gas-phase short peptide chains.
abstract: Aminoisobutyric acid (Aib) is a synthetic amino acid known to favor the formation of 3(10) helical structures in condensed phases, namely, crystals. The intrinsic character of these helicogenic properties has been investigated on the Ac-Aib-Phe-Aib-NH2 molecule under isolated conditions, namely, in the gas phase, both experimentally by double-resonance IR/UV spectroscopy and theoretically by quantum chemistry. A convergent set of evidence, based on energetic, IR, and UV spectroscopic data as well as on analogies with the similar peptide Ac-Ala-Phe-Ala-NH2 previously studied, enables us to conclude the formation of an incipient 310 helix in these isolated systems.
authors.affiliation: Laboratoire Francis Perrin, URA CEA-CNRS 2453, Service des Photons, Atomes et Molécules, CEA Saclay, bât 522, Gif-sur-Yvette Cedex, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Brenner
authors.forename: François
authors.initials: F
authors.lastname: Piuzzi
authors.forename: Iliana
authors.initials: I
authors.lastname: Dimicoli
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tardivel
authors.forename: Michel
authors.initials: M
authors.lastname: Mons
mesh_terms: D000621:Aminoisobutyric Acids / Q000737:chemistry*; D003460:Crystallization; D005740:Gases / Q000737:chemistry*; D007259:Infrared Rays; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry*; D017433:Protein Structure, Secondary; D011789:Quantum Theory; D013057:Spectrum Analysis; D014466:Ultraviolet Rays
chemical_list: D000621:Aminoisobutyric Acids; D005740:Gases; D010455:Peptides