Solid-state NMR shows that dynamically different domains of membrane proteins have different hydration dependence.
Solid-state NMR shows that dynamically different domains of membrane proteins have different hydration dependence.
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DOI：
10.1021/jp503032h
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
Zhengfeng Zhang;Yanke Chen;Xinqi Tang;Jianping Li;Liying Wang;Jun Yang
中科院分区：
文献类型：
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作者：
Zhengfeng Zhang;Yanke Chen;Xinqi Tang;Jianping Li;Liying Wang;Jun Yang
水合作用对膜和膜包埋蛋白的结构、动力学和功能有着深远的影响。到目前为止，人们对膜蛋白在脂质双分子层中的水合反应的分子动力学知之甚少。本文以1,2-二myristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-二myristoyl-sn-glycero-3-phospho-(1'- racc -glycerol) （DMPG）脂质双层中的121残基积分二酰基甘油激酶（DAGK）为模型体系，通过多维魔角旋转（MAS）固态核磁共振（ssNMR）光谱揭示了膜蛋白动态不同结构域的动力学水化依赖性。通过基于标量和偶极耦合的MAS ssNMR实验，分别确定了DAGK的高迁移域和不迁移域及其水分可达性。我们的实验揭示了膜蛋白在高移动域和不移动域的不同水合作用依赖性。我们证明，高移动域的快速、大振幅运动直到20%水化才被触发，在20-50%水化时增强，在50%水化以上时保持不变。相比之下，在亚微秒时间尺度上，不动残基的运动与脂质凝胶相的水化水平无关，在接近凝胶-液晶相变的温度下，围绕双分子层正常的全分子旋转幅度由脂质双分子层的流动性主导，这是一种强烈的水化依赖性。本研究揭示的DAGK动力学的水合依赖性为水合作用与脂质双分子层膜蛋白动力学和功能的相关性提供了新的见解。
Hydration has a profound influence on the structure, dynamics, and functions of membrane and membrane-embedded proteins. So far the hydration response of molecular dynamics of membrane proteins in lipid bilayers is poorly understood. Here, we reveal different hydration dependence of the dynamics in dynamically different domains of membrane proteins by multidimensional magic angle spinning (MAS) solid-state NMR (ssNMR) spectroscopy using 121-residue integral diacylglycerol kinase (DAGK) in 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DMPG) lipid bilayers as a model system. The highly mobile and immobile domains of DAGK and their water accessibilities are identified site-specifically by scalar- and dipolar-coupling based MAS ssNMR experiments, respectively. Our experiments reveal different hydration dependence of the dynamics in highly mobile and immobile domains of membrane proteins. We demonstrate that the fast, large-amplitude motions in highly mobile domains are not triggered until 20% hydration, enhanced at 20-50% hydration and unchanged at above 50% hydration. In contrast, motions on submicrosecond time scale of immobile residues are observed to be independent of the hydration levels in gel phase of lipids, and at the temperature near gel-liquid crystalline phase transition, amplitude of whole-molecule rotations around the bilayer normal is dominated by the fluidity of lipid bilayers, which is strongly hydration dependent. The hydration dependence of the dynamics of DAGK revealed by this study provides new insights into the correlations of hydration to dynamics and function of membrane proteins in lipid bilayers.