Correlating lipid bilayer fluidity with sensitivity and resolution of polytopic membrane protein spectra by solid-state NMR spectroscopy.
Correlating lipid bilayer fluidity with sensitivity and resolution of polytopic membrane protein spectra by solid-state NMR spectroscopy.
复制标题
DOI：
10.1016/j.bbamem.2014.05.003
复制
发表时间：
2015-01
影响因子：
3.4
通讯作者：
Traaseth, Nathaniel J.
中科院分区：
文献类型：
--
作者：
Banigan, James R.;Gayen, Anindita;Traaseth, Nathaniel J.
关键词：
固体核磁共振波谱学已经成为一个很好的工具来研究膜蛋白的结构和动力学在天然的条件下，在脂质双层。实验设计中的关键考虑因素之一是蛋白质的单轴旋转扩散，这可能对NMR光谱观测值产生直接影响。在这方面，温度在调节脂质的相位特性中起着重要作用，这直接影响蛋白质在双层中的旋转扩散速率。事实上，它是公认的，低于脂质双层的主要相变温度的蛋白质的运动显着减慢，而高于此临界温度的速率增加。在这篇文章中，我们进行了一个系统的比较的信号强度和光谱分辨率作为温度的函数，使用魔角旋转（MAS）固态NMR光谱。这些观察值与根据差示扫描量热法（DSC）推断的脂双层的相对流动性直接相关。我们将我们的混合生物物理方法应用于模型膜脂质组合物（DMPC-14：0和DPPC-16：0）存在下的多位膜蛋白多药耐药转运蛋白（EmrE和SugE）。从这些实验中，我们得出结论，旋转扩散给出最佳光谱分辨率对应于~ 5%的双层流动性，其对应于流体或液晶级分中脂质的百分比。在对应于该流动性临界值的温度下，存在足够的流动性以减少在较低温度下发生的不均匀谱线增宽。更大程度的流动性导致更快的单轴旋转扩散和NMR信号强度的S型下降，这源于中间交换动力学，其中运动具有与NMR可观测值相似的频率（即，偶极耦合和化学位移各向异性）。这些实验提供了最佳的温度范围和相应的双层流动性的洞察研究膜蛋白的固态NMR光谱。
Solid-state NMR spectroscopy has emerged as an excellent tool to study the structure and dynamics of membrane proteins under native-like conditions in lipid bilayers. One of the key considerations in experimental design is the uniaxial rotational diffusion of the protein that can have a direct influence on the NMR spectral observables. In this regard, temperature plays a fundamental role in modulating the phase properties of the lipids, which directly influences the rotational diffusion rate of the protein in the bilayer. In fact, it is well established that below the main phase transition temperature of the lipid bilayer the protein’s motion is significantly slowed while above this critical temperature the rate is increased. In this article, we carried out a systematic comparison of the signal intensity and spectral resolution as a function of temperature using magic-angle-spinning (MAS) solid-state NMR spectroscopy. These observables were directly correlated with the relative fluidity of the lipid bilayer as inferred from differential scanning calorimetry (DSC). We applied our hybrid biophysical approach to polytopic membrane protein multidrug resistance transporters (EmrE and SugE) in the presence of model membrane lipid compositions (DMPC-14:0 and DPPC-16:0). From these experiments, we conclude that the rotational diffusion giving optimal spectral resolution corresponds to a bilayer fluidity of ~5%, which corresponds to the percentage of lipids in the fluid or liquid-crystalline fraction. At the temperature corresponding to this critical value of fluidity, there is sufficient mobility to reduce inhomogeneous line broadening that occurs at lower temperatures. A greater extent of fluidity leads to faster uniaxial rotational diffusion and a sigmoidal-type drop in the NMR signal intensity, which stems from intermediate-exchange dynamics where the motion has a similar frequency as the NMR observables (i.e., dipolar couplings and chemical shift anisotropy). These experiments provide insight into the optimal temperature ranges and corresponding bilayer fluidity to study membrane proteins by solid-state NMR spectroscopy.
登录
查看更多内容
DOI：
10.1016/0005-2736(80)90031-0
发表时间：
1980-01-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
--
作者：
GOMEZFERNANDEZ, JC;GONI, FM;CHAPMAN, D
通讯作者：
CHAPMAN, D
影响因子：
5.6
作者：
Fleishman, Sarel J.;Harrington, Susan E.;Ben-Tal, Nir
通讯作者：
Ben-Tal, Nir
影响因子：
4.4
作者：
BENNETT, AE;RIENSTRA, CM;GRIFFIN, RG
通讯作者：
GRIFFIN, RG
影响因子：
1.7
作者：
Baldus, M;Petkova, AT;Griffin, RG
通讯作者：
Griffin, RG
影响因子：
3.4
作者：
Ghimire, Harishchandra;Abu-Baker, Shadi;Lorigan, Gary A.
通讯作者：
Lorigan, Gary A.