School of Pharmaceutical Sciences, Shandong University, Wenhuaxi Road 44, Jinan 250012, China.
School of Pharmaceutical Sciences, Shandong University, Wenhuaxi Road 44, Jinan 250012, China; Key Laboratory of Chemical Biology (Ministry of Education), Shandong University, Wenhuaxi Road 44, Jinan 250012, China; National Glycoengineering Research Center, Shandong University, Binhai Road 72, Qingdao 266200, China.
Int J Biol Macromol. 2019 Oct 1;138:927-932. doi: 10.1016/j.ijbiomac.2019.07.183. Epub 2019 Jul 27.
Hydration plays a fundamental role in maintaining the structure and function of proteins. To get a generalized picture of hydrogen bond network of water surrounding human serum albumin (HSA), near-infrared (NIR) spectroscopy was adopted to explore the hydration induced structural changes of water with HSA concentration from 0.015 to 0.746 mmol/L. As HSA concentration increases, there was a nonlinear change in molar extinction coefficients inconsistent with Beer-Lambert law indicating the changes of hydration water induced by HSA and subsequently confirmed by the hydration number. The decreasing of hydration number with HSA concentration was explained by an overlapping hydration layer model. Resolution of the difference spectra with McCabe-Fisher method and aquaphotomics clearly differentiated the hydrogen bonding of hydration water around HSA. A comparison of resolved hydration spectra highlights that free hydrogen bonded water is present in the hydration layer. As the concentration increased, a more ordered hydrogen bonded water network forms around HSA. These measurements provide unique insight into the relationship between the hydration water and HSA, which is important for understanding the dynamics of protein solution in many biochemical processes, and may serve as a basis for the purification in production.
水合作用在维持蛋白质的结构和功能方面起着至关重要的作用。为了全面了解人血清白蛋白（HSA）周围水的氢键网络，采用近红外（NIR）光谱法研究了水合作用诱导的 HSA 浓度从 0.015 到 0.746mmol/L 时的结构变化。随着 HSA 浓度的增加，摩尔消光系数呈非线性变化，不符合比尔-朗伯定律，这表明 HSA 诱导的水合作用发生了变化，随后通过水合数得到了证实。水合数随 HSA 浓度的降低可以用重叠水合层模型来解释。用 McCabe-Fisher 方法解析差谱和水合光学生物学方法清楚地区分了 HSA 周围水合水中的氢键。解析出的水合光谱的比较突出表明，在水合层中存在游离的氢键合水。随着浓度的增加，HSA 周围形成了更有序的氢键合水网络。这些测量结果提供了对水合水与 HSA 之间关系的独特见解，这对于理解许多生化过程中蛋白质溶液的动力学非常重要，并且可以作为生产中纯化的基础。
