细菌反应调节蛋白RR468磷酸化和去磷酸化关键位点的NMR研究

反应调节蛋白是细菌双组分信号转导系统的重要组分，用于传递来自组氨酸激酶的信号并产生适应性反应.在整个信号转导过程中，反应调节蛋白的磷酸化和去磷酸化最终决定了该系统的信号输出和信号转导终止，因此其磷酸化和去磷酸化作用位点是控制其功能的关键要素．我们以来源于Thermotoga maritima中的反应调节蛋白RR468作为研究对象，将其分别位于loop b3-a3和loop b4-a4上的两个关键位点M55和K85进行突变，通过功能实验验证了这两个残基突变会对蛋白磷酸化和去磷酸化产生影响，并且利用液体核磁共振（NMR）手段对两个突变体的结构和动力学性质进行了研究．

NMR Studies on Key Residues That Affect Phosphorylation and Dephosphorylation Processes of Bacterial Response Regulator RR468

Response regulator proteins are important components of the two-component signal transduction systems, and essential in transferring the signal delivered from the sensor histidine kinase and eliciting an adaptive response. Phosphorylation and dephosphorylation of the response regulator proteins determine the direction of the signal transduction process. The phosphorylation and dephosphorylation sites of the response regulator proteins play an important role in exerting their function. Here we studied some key residues of response regulator RR468 from Thermotoga maritima. Site-directed mutagenesis experiments were performed to the key sites M55 and K85, which are located in loop β3-α3 and loop β4-α4, respectively. The structure and dynamics feature of the two mutants were investigated with liquid nuclear magnetic resonance (NMR) spectroscopy. The results of functional experiments demonstrated that the two residues could affect the phosphorylation and dephosphorylation processes.