Details
| Original language | English |
|---|---|
| Pages (from-to) | 24985-24990 |
| Number of pages | 6 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 19 |
| Issue number | 36 |
| Early online date | 18 Aug 2017 |
| Publication status | Published - 28 Sept 2017 |
Abstract
The steric effects imposed by the isopropyl group of valine in the conformational stabilization of the capped dipeptide N-acetyl-l-valinamide (Ac-Val-NH2) have been studied by laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectroscopy. The rotational and quadrupole coupling constants of the two 14N nuclei determined in this work show that this dipeptide exists as a mixture of C7 and C5 conformers in the supersonic expansion. The conformers are stabilized by a CO⋯H-N intramolecular hydrogen bond closing a seven- or a five-membered ring, respectively. The observation of both conformers is in good agreement with previous results on the related dipeptides containing different residues, confirming that the polarity/non-polarity of the side chains of the amino acid is responsible for the conformational locking/unlocking. The voluminous isopropyl group is not able to prevent the less stable C5 conformer from forming but it destabilizes the CO⋯H-N interaction.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Physical Chemistry Chemical Physics, Vol. 19, No. 36, 28.09.2017, p. 24985-24990.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The role of amino acid side chains in stabilizing dipeptides
T2 - The laser ablation Fourier transform microwave spectrum of Ac-Val-NH2
AU - León, I.
AU - Alonso, E. R.
AU - Mata, S.
AU - Cabezas, C.
AU - Rodríguez, M. A.
AU - Grabow, J. U.
AU - Alonso, J. L.
N1 - Funding Information: The funding from Ministerio de Ciencia e Innovación (Consolider-Ingenio 2010 CSD2009-00038 program ‘‘ASTROMOL’’, CTQ2013-40717-P and CTQ2016-76393-P), Junta de Castilla y León (Grants VA175U13 and VA077U16) and the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC-2013-SyG, Grant Agreement no. 610256 NANO-COSMOS, are gratefully acknowledged. E. R. A. thanks Ministerio de Ciencia e Innovación for FPI grant (BES-2014-067776) and I. L. O. thanks Junta de Castilla y León for a postdoctoral contract; J.-U. G. is indebted to the Deutsche Forschungsgemeinschaft and the Land Niedersachen. Publisher Copyright: © 2017 the Owner Societies. Copyright: Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2017/9/28
Y1 - 2017/9/28
N2 - The steric effects imposed by the isopropyl group of valine in the conformational stabilization of the capped dipeptide N-acetyl-l-valinamide (Ac-Val-NH2) have been studied by laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectroscopy. The rotational and quadrupole coupling constants of the two 14N nuclei determined in this work show that this dipeptide exists as a mixture of C7 and C5 conformers in the supersonic expansion. The conformers are stabilized by a CO⋯H-N intramolecular hydrogen bond closing a seven- or a five-membered ring, respectively. The observation of both conformers is in good agreement with previous results on the related dipeptides containing different residues, confirming that the polarity/non-polarity of the side chains of the amino acid is responsible for the conformational locking/unlocking. The voluminous isopropyl group is not able to prevent the less stable C5 conformer from forming but it destabilizes the CO⋯H-N interaction.
AB - The steric effects imposed by the isopropyl group of valine in the conformational stabilization of the capped dipeptide N-acetyl-l-valinamide (Ac-Val-NH2) have been studied by laser ablation molecular beam Fourier transform microwave (LA-MB-FTMW) spectroscopy. The rotational and quadrupole coupling constants of the two 14N nuclei determined in this work show that this dipeptide exists as a mixture of C7 and C5 conformers in the supersonic expansion. The conformers are stabilized by a CO⋯H-N intramolecular hydrogen bond closing a seven- or a five-membered ring, respectively. The observation of both conformers is in good agreement with previous results on the related dipeptides containing different residues, confirming that the polarity/non-polarity of the side chains of the amino acid is responsible for the conformational locking/unlocking. The voluminous isopropyl group is not able to prevent the less stable C5 conformer from forming but it destabilizes the CO⋯H-N interaction.
UR - http://www.scopus.com/inward/record.url?scp=85029863359&partnerID=8YFLogxK
U2 - 10.1039/c7cp03924g
DO - 10.1039/c7cp03924g
M3 - Article
C2 - 28875198
AN - SCOPUS:85029863359
VL - 19
SP - 24985
EP - 24990
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 36
ER -