TY - JOUR
T1 - Gas-phase peptide structures unraveled by far-IR spectroscopy
T2 - Combining IR-UV ion-dip experiments with born-oppenheimer molecular dynamics simulations
AU - Jaeqx, Sander
AU - Oomens, Jos
AU - Cimas, Alvaro
AU - Gaigeot, Marie Pierre
AU - Rijs, Anouk M.
PY - 2014/4/1
Y1 - 2014/4/1
N2 - 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. The use of low-frequency modes (towards 100 cm-1) for structural assignment of peptides is explored. This far-IR region possibly contains detailed information on the secondary structure. The use of Born-Oppenheimer molecular dynamics simulations is discussed to calculate the far-IR signature of peptides.
AB - 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. The use of low-frequency modes (towards 100 cm-1) for structural assignment of peptides is explored. This far-IR region possibly contains detailed information on the secondary structure. The use of Born-Oppenheimer molecular dynamics simulations is discussed to calculate the far-IR signature of peptides.
KW - conformation analysis
KW - IR spectroscopy
KW - molecular dynamics
KW - peptides
KW - structure elucidation
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U2 - 10.1002/anie.201311189
DO - 10.1002/anie.201311189
M3 - Article
C2 - 24574197
AN - SCOPUS:84897434268
SN - 1433-7851
VL - 53
SP - 3663
EP - 3666
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 14
ER -