Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers.
Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers.
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DOI：
10.1016/j.jmr.2010.08.012
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发表时间：
2010-11
期刊：
影响因子：
--
通讯作者：
Lorigan GA
中科院分区：
文献类型：
--
作者：
Chu S;Maltsev S;Emwas AH;Lorigan GA
提出了一种利用固体核磁共振谱中的顺磁弛豫增强（PRE）测定自旋标记探针膜浸深度的新方法。在1-棕榈酰-2-硬脂酰-sn-甘油-3-磷脂胆碱（PSPC）磷脂双层的不同位置放置DOXYL自旋标记作为顺磁基团，并通过标准反转恢复脉冲序列测量双层表面31P核纵向弛豫（T1）次数的增强。随着DOXYL自旋标记靠近表面以及自旋标记脂质浓度的增加，31P核磁共振自旋晶格弛豫时间稳步下降。自旋标记的位置和浓度与弛豫增强的关系表明，DOXYL自旋标记诱导的PRE对整个膜深度范围内的较长距离具有重要意义。当这些数据与估计的相关时间τc相结合时，我们估计了自旋标记与膜表面31P核之间的r−6加权时间平均距离。固体核磁共振预处理方法与位点定向自旋标记（SDSL）相结合的应用可能是一种测量膜蛋白浸泡深度的有效方法。
A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC) phospholipid bilayers as paramagnetic moieties and the resulting enhancements of the longitudinal relaxation (T1) times of 31P nuclei on the surface of the bilayers were measured by a standard inversion recovery pulse sequence. The 31P NMR spin-lattice relaxation times decrease steadily as the DOXYL spin label moves closer to the surface as well as the concentration of the spin-labeled lipids increase. The enhanced relaxation vs. the position and concentration of spin-labels indicate that PRE induced by the DOXYL spin label are significant to determine longer distances over the whole range of the membrane depths. When these data were combined with estimated correlation times τc, the r−6–weighted, time-averaged distances between the spin labels and the 31P nuclei on the membrane surface were estimated. The application of using this solid-state NMR PRE approach coupled with site-directed spin labeling (SDSL) may be a powerful method for measuring membrane protein immersion depth.
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影响因子：
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