Xu Guohua, Zhao Jiajing, Cheng Kai, Wu Qiong, Liu Xiaoli, Liu Maili, Li Conggang
Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, 430071, P. R. China.
Graduate University of Chinese Academy of Sciences, Beijing, 100029, P. R. China.
Chemistry. 2017 May 17;23(28):6736-6740. doi: 10.1002/chem.201700367. Epub 2017 Apr 18.
Macromolecular crowding and confinement are two factors that potentially affect protein structure and function in a complex cellular environment. The confinement effect on the structure and function of holoCaM [Ca -loaded calmodulin (CaM)], a two-domain protein involved in many calcium-mediated signaling pathways, has been investigated previously. However, little is known about how macromolecular crowding affects holoCaM structure and function. Here, the structure-function correlations of holoCaM are investigated in macromolecular crowded environments. It was found that macromolecular crowding impacts its structure and function mildly. The major conformational states are still extended conformation with inter-domain separation in crowded environment as well as those in dilute solution, but the population of transiently compact conformation increases compared to dilute solution. Furthermore, macromolecular crowding facilitates the binding of CaM with AcN19 peptide (CaM-bind domain of α-syn). This study provides a direct comparison for macromolecular crowding and confinement effects on protein structure and function, which helps to understand chemistry regulation in living cells.
大分子拥挤和受限是在复杂细胞环境中可能影响蛋白质结构和功能的两个因素。先前已经研究了受限对全钙调蛋白（Ca-负载的钙调蛋白，CaM）结构和功能的影响，CaM是一种参与许多钙介导信号通路的双结构域蛋白。然而，关于大分子拥挤如何影响全钙调蛋白的结构和功能知之甚少。在此，研究了在大分子拥挤环境中全钙调蛋白的结构-功能相关性。发现大分子拥挤对其结构和功能的影响较小。在拥挤环境以及稀溶液中，主要构象状态仍然是具有结构域间分离的伸展构象，但与稀溶液相比，瞬时紧密构象的比例增加。此外，大分子拥挤促进了CaM与AcN19肽（α-突触核蛋白的CaM结合结构域）的结合。这项研究为大分子拥挤和受限对蛋白质结构和功能的影响提供了直接比较，有助于理解活细胞中的化学调节。
