Rennella Enrico, Sekhar Ashok, Kay Lewis E
Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada.
Program in Molecular Structure and Function, Hospital for Sick Children , 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.
Biochemistry. 2017 Feb 7;56(5):692-703. doi: 10.1021/acs.biochem.6b01263. Epub 2017 Jan 20.
Protein oligomerization in the cell has important implications for both health and disease, and an understanding of the mechanisms by which proteins can self-associate is, therefore, of critical interest. Initial stages of the oligomerization process can be hard to detect, as they often involve the formation of sparsely populated and transient states that are difficult to characterize by standard biophysical approaches. Using relaxation dispersion nuclear magnetic resonance spectroscopy, we study the oligomerization of human profilin-1, a protein that regulates the polymerization of actin. We show that in solution and at millimolar concentrations profilin-1 is predominantly monomeric. However, fits of concentration-dependent relaxation data are consistent with the formation of a higher-order oligomer that is generated via a multistep process. Together with crystallographic data for profilin-2, a homologue of the protein studied here, our results suggest that profilin-1 forms a sparsely populated tetrameric conformer in solution.
细胞中的蛋白质寡聚化对健康和疾病都具有重要意义，因此，了解蛋白质能够自我缔合的机制至关重要。寡聚化过程的初始阶段可能很难检测到，因为它们通常涉及形成数量稀少且短暂的状态，而这些状态很难用标准生物物理方法进行表征。利用弛豫色散核磁共振波谱，我们研究了人类原肌球蛋白-1（一种调节肌动蛋白聚合的蛋白质）的寡聚化。我们发现，在溶液中且处于毫摩尔浓度时，原肌球蛋白-1主要以单体形式存在。然而，浓度依赖性弛豫数据的拟合结果与通过多步过程生成的高阶寡聚体的形成一致。结合此处所研究蛋白质的同源物原肌球蛋白-2的晶体学数据，我们的结果表明，原肌球蛋白-1在溶液中形成了一种数量稀少的四聚体构象。
