Mechanisms of Protein Stabilization and Prevention of Protein Aggregation by Glycerol
Mechanisms of Protein Stabilization and Prevention of Protein Aggregation by Glycerol
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DOI：
10.1021/bi900649t
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发表时间：
2009-11-24
期刊：
影响因子：
2.9
通讯作者：
Trout, Bernhardt L.
中科院分区：
文献类型：
--
作者：
Vagenende, Vincent;Yap, Miranda G. S.;Trout, Bernhardt L.
蛋白质在水溶液中的稳定性通常通过共溶剂如甘油来增强。已知甘油将天然蛋白质系综转变为更紧凑的状态。甘油还在许多蛋白质的重折叠期间抑制蛋白质聚集。然而，对甘油稳定蛋白质和防止蛋白质聚集的机制的了解仍然缺乏。在这项研究中，我们推导出甘油诱导的蛋白质稳定的机制相结合的热力学框架的优先相互作用与分子水平的洞察溶剂-蛋白质相互作用从分子模拟。与通常的观念，即蛋白质在多元醇/水混合物中的优先水合是由多元醇的分子大小和蛋白质的表面积决定的相反，我们提出的证据表明，蛋白质在甘油/水混合物中的优先水合主要源于静电相互作用，该静电相互作用诱导甘油分子在蛋白质表面的取向，从而进一步排除甘油。这些相互作用使天然蛋白质向更紧凑的构象转变。此外，甘油优先相互作用与大补丁的连续的疏水性，其中甘油作为疏水表面和极性溶剂之间的两亲性界面，因此，我们建议，甘油通过抑制蛋白质展开和通过稳定聚集倾向的中间体，通过优先与疏水表面区域，有利于两亲性界面取向的甘油的相互作用，防止蛋白质聚集。这些机制与文献中的实验数据一致，我们讨论了这些机制适用于其他共溶剂，包括多元醇，精氨酸和尿素的程度。
The stability of proteins in aqueous solution is routinely enhanced by cosolvents such as glycerol. Glycerol is known to shift the native protein ensemble to more compact states. Glycerol also inhibits protein aggregation during the refolding of many proteins. However, mechanistic insight into protein stabilization and prevention of protein aggregation by glycerol is still lacking. In this study, we derive mechanisms of glycerol-induced protein stabilization by combining the thermodynamic framework of preferential interactions with molecular-level insight into solvent-protein interactions gained from molecular simulations. Contrary to the common conception that preferential hydration of proteins in polyol/water mixtures is determined by the molecular size of the polyol and the surface area of the protein, we present evidence that preferential hydration of proteins in glycerol/water mixtures mainly originates from electrostatic interactions that induce orientations of glycerol molecules at the protein surface Such that glycerol is further excluded. These interactions shift the native protein toward more compact conformations. Moreover, glycerol preferentially interacts with large patches of contiguous hydrophobicity where glycerol acts as an amphiphilic interface between the hydrophobic surface and the polar solvent, Accordingly, we propose that glycerol prevents protein aggregation by inhibiting protein unfolding and by stabilizing aggregation-prone intermediates through preferential interactions with hydrophobic surface regions that favor amphiphilic interface orientations of glycerol. These mechanisms agree well with experimental data available in the literature, and we discuss the extent to which these mechanisms apply to other cosolvents, including polyols, arginine, and urea.