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Raman Spectroscopic Signature of Ectoine Conformations in Bulk Solution and Crystalline State
Author(s) -
Solomun Tihomir,
Hahn Marc Benjamin,
Smiatek Jens
Publication year - 2020
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.202000457
Subject(s) - ectoine , raman spectroscopy , chemistry , aqueous solution , molecule , chemical physics , density functional theory , crystallography , molecular dynamics , conformational change , computational chemistry , stereochemistry , organic chemistry , biochemistry , physics , amino acid , osmoprotectant , optics , proline
Recent crystallographic results revealed conformational changes of zwitterionic ectoine upon hydration. By means of confocal Raman spectroscopy and density functional theory calculations, we present a detailed study of this transformation process as part of a Fermi resonance analysis. The corresponding findings highlight that all resonant couplings are lifted upon exposure to water vapor as a consequence of molecular binding processes. The importance of the involved molecular groups for water binding and conformational changes upon hydration is discussed. Our approach further shows that the underlying rapid process can be reversed by carbon dioxide saturated atmospheres. For the first time, we also confirm that the conformational state of ectoine in aqueous bulk solution coincides with crystalline ectoine in its dihydrate state, thereby highlighting the important role of a few bound water molecules.