Stability of Protein-Specific Hydration Shell on Crowding.
Stability of Protein-Specific Hydration Shell on Crowding.
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DOI：
10.1021/jacs.6b01989
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发表时间：
2016-04-27
影响因子：
15
通讯作者：
Han S
中科院分区：
文献类型：
--
作者：
Huang KY;Kingsley CN;Sheil R;Cheng CY;Bierma JC;Roskamp KW;Khago D;Martin RW;Han S
我们证明了蛋白质拥挤的影响严重依赖于蛋白质水合壳的稳定性，这在不同的蛋白质之间可能会有很大的不同。在人眼晶状体中，γS-crystallin （γS-WT）形成致密的透明水凝胶，具有较高的折射率，是研究蛋白质拥挤效应的理想体系。单点突变产生与白内障相关的γS-G18V变异，显著改变眼球晶状体的光学特性。该系统为利用γS-WT和γS-G18V探索蛋白质拥挤效应的基本问题提供了机会：(i)水合水的扩散动力学如何作为蛋白质拥挤的函数而变化？（ii）在γS-WT形成水凝胶后，是否发生了一个动态转变，产生单一的水化水种群，还是散装水种群和水化水种群共存？利用局域自旋探针分别探测了γ - s - wt和γ - s - g18v在溶液中表面水化和间隙水的局部平移扩散率。令人惊讶的是，我们发现，在高达500 mg/mL的高度拥挤的γS-WT浓度下，在水凝胶形成的影响下，蛋白质水合壳保持了显著的动态，与约5 mg/mL的稀释蛋白质溶液相比，如果有的话，速度会减慢不到两倍。在自拥挤时，这种强大的表面水合水的种群增加，而即使在~500 mg/mL的蛋白质浓度下，也存在显着的块状水种群。相比之下，γ -s - g18v的地表水随着溶液浓度的适度增加或溶液条件的细微改变而不可逆脱水，这表明蛋白质拥挤的影响高度依赖于蛋白质特异性水合壳的稳定性。γ - s -晶体蛋白在眼晶状体中的核心功能可能正是其保持强大水合壳的能力，其稳定性被单个G18V突变所破坏。
We demonstrate that the effect of protein crowding is critically dependent on the stability of the protein’s hydration shell, which can dramatically vary between different proteins. In the human eye lens, γS-crystallin (γS-WT) forms a densely packed transparent hydrogel with a high refractive index, making it an ideal system for studying the effects of protein crowding. A single point mutation generates the cataract-related variant γS-G18V, dramatically altering the optical properties of the eye lens. This system offers an opportunity to explore fundamental questions regarding the effect of protein crowding, using γS-WT and γS-G18V: (i) how do the diffusion dynamics of hydration water change as a function of protein crowding?; and (ii) upon hydrogel formation of γS-WT, has a dynamic transition occurred generating a single population of hydration water, or do populations of bulk and hydration water coexist? Using localized spin probes, we separately probe the local translational diffusivity of both surface hydration and interstitial water of γS-WT and γS-G18V in solution. Surprisingly, we find that under the influence of hydrogel formation at highly crowded γS-WT concentrations up to 500 mg/mL, the protein hydration shell remains remarkably dynamic, slowing by less than a factor of two, if at all, compared to that in dilute protein solutions of ~5 mg/mL. Upon self-crowding, the population of this robust surface hydration water increases, while a significant bulk-like water population coexists even at ~500 mg/mL protein concentrations. In contrast, surface water of γS-G18V irreversibly dehydrates with moderate concentration increases or subtle alterations to the solution conditions, demonstrating that the effect of protein crowding is highly dependent on the stability of the protein-specific hydration shell. The core function of γS-crystallin in the eye lens may be precisely its capacity to preserve a robust hydration shell, whose stability is abolished by a single G18V mutation.
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影响因子：
3.4
作者：
Augusteyn, Robert C.
通讯作者：
Augusteyn, Robert C.
影响因子：
3.7
作者：
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作者：
Hatters, DM;Minton, AP;Howlett, GJ
通讯作者：
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作者：
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通讯作者：
Williamson, MP
影响因子：
3.4
作者：
Brubaker, William D.;Freites, J. Alfredo;Martin, Rachel W.
通讯作者：
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