使用用于静态和 MAS 固态 NMR 光谱学的偏振优化实验 (POE) 测定脂质双层中膜蛋白的结构拓扑。
Determination of structural topology of a membrane protein in lipid bilayers using polarization optimized experiments (POE) for static and MAS solid state NMR spectroscopy.
机构信息
Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
出版信息
J Biomol NMR. 2013 Oct;57(2):91-102. doi: 10.1007/s10858-013-9766-2. Epub 2013 Aug 21.
The low sensitivity inherent to both the static and magic angle spinning techniques of solid-state NMR (ssNMR) spectroscopy has thus far limited the routine application of multidimensional experiments to determine the structure of membrane proteins in lipid bilayers. Here, we demonstrate the advantage of using a recently developed class of experiments, polarization optimized experiments, for both static and MAS spectroscopy to achieve higher sensitivity and substantial time-savings for 2D and 3D experiments. We used sarcolipin, a single pass membrane protein, reconstituted in oriented bicelles (for oriented ssNMR) and multilamellar vesicles (for MAS ssNMR) as a benchmark. The restraints derived by these experiments are then combined into a hybrid energy function to allow simultaneous determination of structure and topology. The resulting structural ensemble converged to a helical conformation with a backbone RMSD ~0.44 Å, a tilt angle of 24° ± 1°, and an azimuthal angle of 55° ± 6°. This work represents a crucial first step toward obtaining high-resolution structures of large membrane proteins using combined multidimensional oriented solid-state NMR and magic angle spinning solid-state NMR.
固态 NMR(ssNMR)光谱学中的静态和魔角旋转技术固有的低灵敏度迄今为止限制了多维实验的常规应用,无法确定脂质双层中膜蛋白的结构。在这里,我们展示了使用最近开发的一类实验(极化优化实验)的优势,用于静态和 MAS 光谱学,以实现更高的灵敏度,并为 2D 和 3D 实验节省大量时间。我们使用肌联蛋白(一种单通道膜蛋白)作为基准,其在定向双分子层囊泡(用于定向固态 NMR)和多层囊泡(用于 MAS 固态 NMR)中再构成。然后,将这些实验得出的约束条件组合到一个混合能量函数中,以允许同时确定结构和拓扑。得到的结构集合收敛到一个螺旋构象,其骨架 RMSD 约为 0.44 Å,倾斜角为 24°±1°,方位角为 55°±6°。这项工作代表了使用组合多维定向固态 NMR 和魔角旋转固态 NMR 获得大型膜蛋白高分辨率结构的重要的第一步。