分离局部场实验的灵敏度增强:在膜蛋白中的应用。
Sensitivity enhancement of separated local field experiments: application to membrane proteins.
机构信息
Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
出版信息
J Phys Chem B. 2010 Apr 22;114(15):5089-95. doi: 10.1021/jp909778a.
Separated local field (SLF) experiments have been used for almost three decades to obtain structural information in solid-state NMR. These experiments resolve chemical shift anisotropy (CSA) from dipole-dipole interactions (dipolar couplings, DC) in isolated spin systems. Both CSA and DC data can be converted into orientational constraints to elucidate the secondary structure and topology of membrane proteins in oriented lipid bilayers. Here, we propose a new suite of sensitivity enhanced SLF pulse sequences to measure CSA and DC for aligned membrane proteins and liquid crystalline molecules that will decrease the time needed for data acquisition. We demonstrate the efficacy of these new sensitivity enhanced experiments using both a single crystal of N-acetyl leucine and a single pass membrane protein sarcolipin reconstituted in aligned lipid bicelles. These results lay the groundwork for the routine application of this methodology for studying the structure and topology of membrane proteins.
分离局部场(SLF)实验已被用于获取固态 NMR 中的结构信息近三十年。这些实验可以在孤立的自旋系统中解析化学位移各向异性(CSA)和偶极-偶极相互作用(偶极耦合,DC)。CSA 和 DC 数据都可以转换为取向约束,以阐明在定向脂质双层中膜蛋白的二级结构和拓扑结构。在这里,我们提出了一套新的灵敏度增强的 SLF 脉冲序列,用于测量排列的膜蛋白和液晶分子的 CSA 和 DC,这将减少数据采集所需的时间。我们使用 N-乙酰亮氨酸单晶和在定向脂质双体中重组的单次通过膜蛋白肌浆球蛋白来证明这些新的灵敏度增强实验的有效性。这些结果为该方法在研究膜蛋白结构和拓扑方面的常规应用奠定了基础。