Analysis of the Hydration Water around Bovine Serum Albumin Using Terahertz Coherent Synchrotron Radiation

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• 作者：Jordan W. Bye ; Stefano Meliga ; Denis Ferachou ; Gianfelice Cinque ; J. Axel Zeitler ; Robert J. Falconer
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：January 9, 2014
• 年：2014
• 卷：118
• 期：1
• 页码：83-88
• 全文大小：318K
• ISSN：1520-5215

文摘

Terahertz spectroscopy was used to study the absorption of bovine serum albumin (BSA) in water. The Diamond Light Source operating in a low alpha mode generated coherent synchrotron radiation that covered a useable spectral bandwidth of 0.3鈥?.3 THz (10鈥?10 cm^鈥?). As the BSA concentration was raised, there was a nonlinear change in absorption inconsistent with Beer鈥檚 law. At low BSA concentrations (0鈥? mM), the absorption remained constant or rose slightly. Above a concentration of 1 mM BSA, a steady decrease in absorption was observed, which was followed by a plateau that started at 2.5 mM. Using a overlapping hydration layer model, the hydration layer was estimated to extend 15 脜 from the protein. Calculation of the corrected absorption coefficient (伪_corr) for the water around BSA by subtracting the excluded volume of the protein provides an alternative approach to studying the hydration layer that provides evidence for complexity in the population of water around BSA.