Interaction between tau and water during the induced aggregation revealed by near-infrared spectroscopy
Interaction between tau and water during the induced aggregation revealed by near-infrared spectroscopy
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近红外光谱揭示诱导聚集过程中 tau 蛋白与水之间的相互作用
DOI：
10.1016/j.saa.2020.118046
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Shao Xueguang
中科院分区：
文献类型：
--
作者：
Sun Yan;Ma Li;Cai Wensheng;Shao Xueguang
近红外 (NIR) 光谱对水结构的变化很敏感。在这项工作中，使用近红外光谱研究了肝素诱导的 R2/wt 聚集过程中水合水的变化。渗透剂尿素和海藻糖用于减缓和加速聚集。采用近红外光谱在 37 °C 下获得的 R2/wt 水溶液的光谱来分析聚集过程中水的结构。通过主成分分析（PCA）从分辨率增强的近红外光谱中观察到不同水种的光谱特征。提出了R2/wt的NH和CH基团周围分别存在具有1个和2个氢键的水分子，并且发现氢键水的变化是监测聚集过程的指标。然后，通过二维相关光谱分析了聚集过程中水物种的变化。发现与NH基团氢键结合的水比疏水基团周围的水更早发生变化。结果表明，β-折叠在聚集初期通过酰胺基团的氢键形成，侧链周围水的氢键网络的破坏可能是有序淀粉样纤维形成的主要原因。
Near-infrared (NIR) spectra are sensitive to the variation of water structure. In this work, NIR spectroscopy was used to investigate the variation of hydration water during the aggregation of R2/wt induced by heparin. The osmolytes, urea and trehalose, were used to slow down and speed up the aggregation. The spectra of R2/wt aqueous solution obtained by NIR spectroscopy at 37 °C were adopted to analyze the structure of water during the aggregation. The spectral features of different water species were observed by principal component analysis (PCA) from the resolution enhanced NIR spectra. The existence of the water molecules with one and two hydrogen bonds around the NH and CH groups of R2/wt, respectively, was suggested, and the variation of the hydrogen-bonded water was found to be an indicator to monitor the process of aggregation. Then, the variation of the water species during the aggregation was analyzed by two-dimensional correlation spectroscopy. The water hydrogen bonded with NH group was found to change earlier than the water around the hydrophobic groups. The results suggest that β-sheet forms though the hydrogen bonds of amide groups in the early stage of the aggregation, and the destruction of the hydrogen bond network of the water around the side chains maybe the main reason for the formation of the ordered amyloid fibers.