Extended Law of Corresponding States Applied to Solvent Isotope Effect on a Globular Protein

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• 作者：Saskia Bucciarelli ; Najet Mahmoudi ; Lucía Casal-Dujat ; Marie Jéhannin ; Corinne Jud ; Anna Stradner
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2016
• 出版时间：May 5, 2016
• 年：2016
• 卷：7
• 期：9
• 页码：1610-1615
• 全文大小：463K
• 年卷期：0
• ISSN：1948-7185

文摘

Investigating proteins with techniques such as NMR or neutron scattering frequently requires the partial or complete substitution of D₂O for H₂O as a solvent, often tacitly assuming that such a solvent substitution does not significantly alter the properties of the protein. Here, we report a systematic investigation of the solvent isotope effect on the phase diagram of the lens protein γB-crystallin in aqueous solution as a model system exhibiting liquid–liquid phase separation. We demonstrate that the observed strong variation of the critical temperature T_c can be described by the extended law of corresponding states for all H₂O/D₂O ratios, where scaling of the temperature by T_c or the reduced second virial coefficient accurately reproduces the binodal, spinodal, and osmotic compressibility. These findings highlight the impact of H₂O/D₂O substitution on γB-crystallin properties and warrant further investigations into the universality of this phenomenon and its underlying mechanisms.