Electrostatic Potentials around the Proteins Preferably Crystallized by Ammonium Sulfate
Electrostatic Potentials around the Proteins Preferably Crystallized by Ammonium Sulfate
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DOI：
10.1021/acs.cgd.0c01136
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发表时间：
2021-01-06
影响因子：
3.8
通讯作者：
Hoshino, Tyuji
中科院分区：
文献类型：
--
作者：
Guo, Yan;Qu, Liang;Hoshino, Tyuji
硫酸铵 (AS) 是蛋白质结晶中最常用的沉淀剂之一。然而，AS 并不总是对所有种类的蛋白质都有效。有些蛋白质很容易利用 AS 结晶，而另一些则不然。聚乙二醇 (PEG) 也经常用于蛋白质结晶。为了阐明蛋白质在晶体生长过程中偏爱沉淀剂的原因，我们研究了 100 种经高浓度 AS 结晶的蛋白质的静电势。大多数蛋白质的静电势等值面具有共同的形状。静电势的正负区域几乎相等。正负区域之间的接触仅限于蛋白质表面的狭窄区域。即使在接触区域，静电势的分离也是整齐的。相反，对于优选通过 PEG 结晶的蛋白质，阳性区域和阴性区域之间的分离并不明显。静电势的正负区域是碎片化的，接触区域的等值面复杂。这些发现表明，不仅 AS 离子和蛋白质分子之间的局部相互作用，而且蛋白质的周围环境也对晶体生长负责。
Ammonium sulfate (AS) is one of the most popular precipitants in protein crystallization. However, AS is not always effective for all kinds of proteins. Some proteins are easily crystallized by utilizing AS, while others are not. Polyethylene glycols (PEGs) is also frequently used in protein crystallization. To clarify the reason a protein has a preference for a precipitant in crystal growth, we investigated electrostatic potentials for 100 kinds of proteins that had been crystallized by high concentrations of AS. Most of the proteins have a common shape for the isosurface of their electrostatic potentials. The positive and negative areas of electrostatic potential are almost equally separated. The contact between the positive and negative areas is limited to a narrow region on the protein surface. The separation of the electrostatic potential is neat even at the contact region. In contrast, the separation between positive and negative areas is not clear for the proteins preferably crystallized by PEGs. The positive and negative areas of electrostatic potential are fragmentary, and the isosurface at the contact region is complicated. These findings suggest that not only the local interaction between AS ions and a protein molecule but also the surroundings of the protein are responsible for crystal growth.