Laboratoire de Chimie Physique Moléculaire, École Polytechnique Fédérale de Lausanne, Station-6, 1015 Lausanne, Switzerland.
J Phys Chem Lett. 2021 Jan 21;12(2):907-911. doi: 10.1021/acs.jpclett.0c03678. Epub 2021 Jan 13.
The native-like structures of protonated glycine and peptide GlyH were elucidated using cold ion IR spectroscopy of these biomolecules hydrated by a controlled number of water molecules. The complexes were generated directly from an aqueous solution using gentle electrospray ionization. Already with a single retained water molecule, GlyH exhibits the native-like structure characterized by a lack of intramolecular hydrogen bonds. We use our spectra to calibrate the available data for the same complexes, which are produced by cryogenic condensation of water onto the gas-phase glycine. In some conformers of these complexes, GlyH adopts the native-like structure, while in the others, it remains "kinetically" trapped in the intrinsic state. Upon condensation of 4-5 water molecules, the embedded amino acid fully adopts its native-like structure. Similarly, condensation of one water molecule onto the tripeptide is insufficient to fully eliminate its kinetically trapped intrinsic states.
使用受控数目的水分子水合的质子化甘氨酸和肽 GlyH 的冷离子 IR 光谱阐明了类似天然的结构。这些复合物是直接从水溶液中通过温和的电喷雾电离产生的。即使只有一个保留的水分子，GlyH 也表现出类似天然的结构，其特征是缺乏分子内氢键。我们使用我们的光谱来校准相同复合物的可用数据，这些复合物是通过将水冷冻冷凝到气相甘氨酸上产生的。在这些复合物的一些构象中，GlyH 采用类似天然的结构，而在其他构象中，它仍然“动力学上”被困在本征状态。在冷凝 4-5 个水分子后，嵌入的氨基酸完全采用其类似天然的结构。类似地，将一个水分子冷凝到三肽上不足以完全消除其动力学上被困的本征状态。
