Gas‐Phase Peptide Structures Unraveled by Far‐IR Spectroscopy: Combining IR‐UV Ion‐Dip Experiments with Born–Oppenheimer Molecular Dynamics Simulations |
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| Authors: | Sander Jaeqx Prof Dr Jos Oomens Dr Alvaro Cimas Prof Dr Marie‐Pierre Gaigeot Dr Anouk M Rijs |
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| Institution: | 1. Radboud University Nijmegen, Institute for Molecules and Materials, FELIX facility Toernooiveld 7, 6525 ED Nijmegen (The Netherlands);2. Université d'Evry val d'Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement, LAMBE UMR CNRS 8587, Boulevard F. Mitterrand, Bat Maupertuis, 91025 Evry (France) |
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| Abstract: | Vibrational spectroscopy provides an important probe of the three‐dimensional structures of peptides. With increasing size, these IR spectra become very complex and to extract structural information, comparison with theoretical spectra is essential. Harmonic DFT calculations have become a common workhorse for predicting vibrational frequencies of small neutral and ionized gaseous peptides. 1 Although the far‐IR region (<500 cm?1) may contain a wealth of structural information, as recognized in condensed phase studies, 2 DFT often performs poorly in predicting the far‐IR spectra of peptides. Here, Born–Oppenheimer molecular dynamics (BOMD) is applied to predict the far‐IR signatures of two γ‐turn peptides. Combining experiments and simulations, far‐IR spectra can provide structural information on gas‐phase peptides superior to that extracted from mid‐IR and amide A features. |
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| Keywords: | conformation analysis IR spectroscopy molecular dynamics peptides structure elucidation |
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