Bundesanstalt für Materialforschung und -prüfung (BAM), 12205, Berlin, Germany.
Freie Universität Berlin, Institut für Experimentalphysik, 14195, Berlin, Germany.
Chemphyschem. 2020 Sep 2;21(17):1945-1950. doi: 10.1002/cphc.202000457. Epub 2020 Aug 17.
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.
最近的晶体学结果揭示了两性离子羟乙基甘氨酸在水合作用下的构象变化。通过共聚焦拉曼光谱和密度泛函理论计算，我们对这一转变过程进行了详细研究，作为费米共振分析的一部分。相应的发现强调，所有共振耦合在暴露于水蒸气时都会被解除，这是分子结合过程的结果。讨论了涉及的分子基团在水结合和水合作用构象变化中的重要性。我们的方法还进一步表明，基础的快速过程可以被二氧化碳饱和气氛逆转。我们首次还证实，在水溶液中游离态的羟乙基甘氨酸的构象状态与二水合晶体羟乙基甘氨酸的状态一致，从而突出了少数结合水分子的重要作用。
