Gas-Phase Conformational Map of the Amino Acid Isovaline |
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Authors: | Dr E M Neeman Dr I León Dr E R Alonso S Mata Prof J L Alonso |
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Institution: | Grupo de Espectroscopia Molecular (GEM), Edificio Quifima Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico Universidad de Valladolid, 47011 Valladolid, Spain |
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Abstract: | Four conformers of the non-proteinogenic α-amino acid isovaline, vaporized by laser ablation, are characterized by Fourier-transform microwave techniques in a supersonic expansion. The comparison between the experimental rotational and 14N nuclear quadrupole coupling constants and the ab initio calculated ones provides conclusive evidence for the identification of the conformers. The most stable species is stabilized by an N−H⋅⋅⋅O =C intramolecular hydrogen bond and a cis-COOH interaction, whereas the higher-energy conformers exhibit an N⋅⋅⋅H−O intramolecular hydrogen bond and trans-COOH, as in other aliphatic amino acids. The spectroscopic data herein reported can be used for the astrophysical purpose in a possible detection of isovaline in space. |
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Keywords: | amino acids isovaline intramolecular interactions laser ablation rotational spectroscopy |
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