Thermodynamic stability of hnRNP A1 low complexity domain revealed by high-pressure NMR.
Thermodynamic stability of hnRNP A1 low complexity domain revealed by high-pressure NMR.
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我们已经研究了压力和温度引起的构象变化与hnRNP A1，RNA结合蛋白能够响应细胞应激相分离的低复杂性结构域。在1至2，500 bar和268 K至290 K范围内收集了与蛋白质-G B1结构域融合的hnRNP A1低复杂性结构域的溶液NMR光谱。虽然GB 1域显示出典型的压力引起的和冷温度引起的展开预期的小球状域，低复杂性域的hnRNP A1表现出不寻常的压力和温度依赖性。我们观察到，低复杂度域是压力敏感的，在规定的压力范围内进行主要的构象转变。值得注意的是，这种转变具有典型的折叠-展开转变的逆温度依赖性。我们的研究结果表明，存在一个低洼的扩展，并充分溶剂化状态（S）的低复杂性域，可能发挥作用，在相分离。这项研究突出了精致的灵敏度的溶液NMR光谱观察细微的构象变化，并说明了如何压力扰动可以用来确定亚稳态构象合奏的属性。
We have investigated the pressure- and temperature-induced conformational changes associated with the low complexity domain of hnRNP A1, an RNA-binding protein able to phase separate in response to cellular stress. Solution NMR spectra of the hnRNP A1 low-complexity domain fused with protein-G B1 domain were collected from 1 to 2,500 bar and from 268 K to 290 K. While the GB1 domain shows the typical pressure-induced and cold temperature-induced unfolding expected for small globular domains, the low-complexity domain of hnRNP A1 exhibits unusual pressure and temperature dependences. We observed that the low-complexity domain is pressure sensitive, undergoing a major conformational transition within the prescribed pressure range. Remarkably, this transition has the inverse temperature dependence of a typical folding-unfolding transition. Our results suggest the presence of a low-lying extended, and fully solvated state(s) of the low-complexity domain that may play a role in phase separation. This study highlights the exquisite sensitivity of solution NMR spectroscopy to observe subtle conformational changes and illustrates how pressure perturbation can be used to determine the properties of metastable conformational ensembles.