Structural rigidity of a large cavity-containing protein revealed by high-pressure crystallography
Structural rigidity of a large cavity-containing protein revealed by high-pressure crystallography
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DOI：
10.1016/j.jmb.2006.12.021
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发表时间：
2007-03-30
影响因子：
5.6
通讯作者：
Gruner, Sol M.
中科院分区：
文献类型：
--
作者：
Collins, Marcus D.;Quillin, Michael L.;Gruner, Sol M.
空间限制、带电相互作用和许多其他对蛋白质结构和功能重要的作用力都可以通过诱变实验来探索。这类研究导致了关于什么使蛋白质稳定在折叠状态的丰富知识。为了获得更完整的图像，我们需要以一种连续的方式干扰这些结构，这是突变无法实现的。有了高压结晶学方法，现在就有可能在不断改变热力学参数的同时探索蛋白质的详细性质。在这里，我们详细描述了T4溶菌酶的空洞突变体L99A以及它的假野生型(WT*)对静水压力的结构响应。令人惊讶的是，空腔对压力响应几乎没有影响：在WT*中观察到的变化几乎与L99A在压力下观察到的变化相同。空洞是最刚性的，而其他区域变形很大。这意味着，虽然一些残基可能会增加蛋白质的热力学稳定性，但它们也可能在结构上是无关的。如最近所示，在保持整体尺寸不变的情况下，空腔在100兆帕以上的压力下充满水。蛋白质的结果图是这样一幅图，其中构象波动的侧基提供了类似液体的环境，但这也有助于肽骨架的刚性。(C)2006爱思唯尔有限公司。保留所有权利。
Steric constraints, charged interactions and many other forces important to protein structure and function can be explored by mutagenic experiments. Research of this kind has led to a wealth of knowledge about what stabilizes proteins in their folded states. To gain a more complete picture requires that we perturb these structures in a continuous manner, something mutagenesis cannot achieve. With high pressure crystallographic methods it is now possible to explore the detailed properties of proteins while continuously varying thermodynamic parameters. Here, we detail the structural response of the cavity-containing mutant L99A of T4 lysozyme, as well as its pseudo wild-type (WT*) counterpart, to hydrostatic pressure. Surprisingly, the cavity has almost no effect on the pressure response: virtually the same changes are observed in WT* as in L99A under pressure. The cavity is most rigid, while other regions deform substantially. This implies that while some residues may increase the thermodynamic stability of a protein, they may also be structurally irrelevant. As recently shown, the cavity fills with water at pressures above 100 MPa while retaining its overall size. The resultant picture of the protein is one in which conformationally fluctuating side groups provide a liquid-like environment, but which also contribute to the rigidity of the peptide backbone. (c) 2006 Elsevier Ltd. All rights reserved.