Biophysical properties of the extra-cellular domain of the calcium-sensing receptor.
Biophysical properties of the extra-cellular domain of the calcium-sensing receptor.
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钙敏感受体胞外域的生物物理特性。
DOI：
10.1016/j.bbrc.2006.08.047
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发表时间：
2006
影响因子：
3.1
通讯作者：
Kumar,Rajiv
中科院分区：
文献类型：
--
作者：
Ryan,ZacharyC;Craig,TheodoreA;Venyaminov,SergeiYu;Thompson,JamesR;Kumar,Rajiv
钙敏感受体（CaSR）是一种g蛋白偶联受体，通过改变甲状旁腺激素的释放来调节钙稳态，并结合二价和三价阳离子、氨基酸、多胺和多阳离子配体。为了获得有关CaSR结构特性的信息，我们表达了毫克量的纯、均质和人类CaSR细胞外结构域的功能片段（残基20-535）。表达和纯化的蛋白被折叠并结合新霉素和钙。在没有还原剂（如β-巯基乙醇）的情况下形成二聚体。热变性研究表明，其展开焓值和熵值分别为ΔH=−178±4kJ/mol和ΔS=−535±13J/mol/K。该蛋白具有明显的二级结构，α-螺旋、β-片状、β-弯状和无序含量分别为36.6±6.7%、13.3±5.3%、20.2±3.3%和29.4±4.0%。所描述的表达和纯化CaSR的方法应该证明对这种生理上重要的蛋白质的进一步结构研究是有用的。
The Calcium-Sensing Receptor (CaSR) is a G-protein-coupled receptor that regulates calcium homeostasis by altering parathyroid hormone release, and which binds divalent and trivalent cations, amino acids, polyamines, and polycationic ligands. To obtain information about the structural properties of the CaSR, we expressed milligram quantities of a pure, homogeneous, and functional fragment of the human CaSR extracellular domain (residues 20–535). The expressed and purified protein is folded and binds both neomycin and calcium. It forms dimers in the absence of reducing agents such as β-mercaptoethanol. Thermal denaturation studies show it has enthalpy and entropy values of unfolding equal to ΔH=−178±4kJ/mol and ΔS=−535±13J/mol/K. The protein has significant secondary structure with α-helical, β-sheet, β-turns, and disordered content of 36.6±6.7%, 13.3±5.3%, 20.2±3.3%, and 29.4±4.0%, respectively. The described method for the expression and purification of CaSR should prove useful for further structural studies of this physiologically important protein.