pH-dependent structural change of the extracellular sensor domain of the DraK histidine kinase from Streptomyces coelicolor.
pH-dependent structural change of the extracellular sensor domain of the DraK histidine kinase from Streptomyces coelicolor.
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DOI：
10.1016/j.bbrc.2013.01.018
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发表时间：
2013-02
影响因子：
3.1
通讯作者：
K. Yeo;Eun Hye Kim;E. Hwang;Young-Hyun Han;Y. Eo;H. Kim;O. Kwon;Young-Soo Hong;C. Cheong;H. Cheong
中科院分区：
文献类型：
--
作者：
K. Yeo;Eun Hye Kim;E. Hwang;Young-Hyun Han;Y. Eo;H. Kim;O. Kwon;Young-Soo Hong;C. Cheong;H. Cheong
近年来，天蓝色链霉菌（Streptomycescoelicolor）的DraR/DraK（Sco 3063/Sco 3062）双组分系统（TCS）参与了抗生素生物合成的差异调节。然而，尚未显示在何种条件下以及如何激活DraR/DraK TCS以启动信号转导过程。因此，要了解的感觉机制，结构的DraK的感觉域的研究是非常必要的。在这里，我们报告的生化和生物物理特性的细胞外感觉域（ESD）的DraK。我们观察到一个可逆的pH依赖性的构象变化的ESD在pH范围为2.5-10。尺寸排阻色谱和AUC（分析超离心）数据表明，ESD在溶液中主要是单体，并在酸性条件下存在于单体和二聚体状态之间的平衡。使用NMR（核磁共振）和CD（圆二色性）光谱，我们的研究结果表明，在低pH值的ESD的结构比在高pH值的结构。特别是，谷氨酸在位置83是一个重要的残基的pH依赖性的构象变化。这些结果表明，这种pH依赖性的ESD的构象变化可能参与的信号转导过程中的DraR/DraK TCS。
Recently, the DraR/DraK (Sco3063/Sco3062) two-component system (TCS) of Streptomycescoelicolor has been reported to be involved in the differential regulation of antibiotic biosynthesis. However, it has not been shown that under which conditions and how the DraR/DraK TCS is activated to initiate the signal transduction process. Therefore, to understand the sensing mechanism, structural study of the sensory domain of DraK is highly required. Here, we report the biochemical and biophysical properties of the extracellular sensory domain (ESD) of DraK. We observed a reversible pH-dependent conformational change of the ESD in a pH range of 2.5–10. Size-exclusion chromatography and AUC (analytical ultracentrifugation) data indicated that the ESD is predominantly monomeric in solution and exists in equilibrium between monomer and dimer states in acidic condition. Using NMR (nuclear magnetic resonance) and CD (circular dichroism) spectroscopy, our findings suggest that the structure of the ESD at low pH is more structured than that at high pH. In particular, the glutamate at position 83 is an important residue for the pH-dependent conformational change. These results suggest that this pH-dependent conformational change of ESD may be involved in signal transduction process of DraR/DraK TCS.