A carbon-13 nuclear magnetic resonance spectroscopic study of inter-proton pair order parameters: a new approach to study order and dynamics in phospholipid membrane systems.
A carbon-13 nuclear magnetic resonance spectroscopic study of inter-proton pair order parameters: a new approach to study order and dynamics in phospholipid membrane systems.
复制标题
质子对间有序参数的碳 13 核磁共振波谱研究：研究磷脂膜系统有序和动力学的新方法。
DOI：
10.1016/s0006-3495(98)74055-x
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发表时间：
1998
影响因子：
3.4
通讯作者：
Oldfield,E
中科院分区：
文献类型：
--
作者：
Urbina,JA;Moreno,B;Arnold,W;Taron,CH;Orlean,P;Oldfield,E
本文报道了一种简单的新型核磁共振（NMR）光谱方法，利用高分辨率13c交叉极化/魔角自旋（CP/MAS）核磁共振结合1h偶极回波制备得到了磷脂中质子对间序参数。由此产生的二维核磁共振光谱允许确定每个解析13c位点上的质子的运动平均对间秒矩，由此可以推导出相应的对间序参数。交叉极化前的自旋锁混合脉冲可以检测脂质分子不同区域之间的自旋扩散。该方法适用于多种模型膜系统，包括1,2-二myristoyl- n-glycero-3-phosphocholine (DMPC)/甾醇和1- palmityl -2- oil - yl- cn -glycero-3-phosphocholine (POPC)/甾醇模型膜。结果与先前使用氘标记或过氘化磷脂分子的研究结果一致。还发现有效的自旋扩散发生在磷脂酰基链内，以及这些分子的甘油主链和胆碱头基之间。该实验还应用于生物合成13c标记麦角甾醇加入磷脂酰胆碱双分子层。这些结果表明，甾醇核和脂肪侧链的运动都受到高度限制，这些结构不同的区域之间有有效的自旋交换。最后，研究了1,2-二酰基-锡-甘油-3-磷酸乙醇胺（DOPE）的层状液晶（Lα）和倒六方（HII）相。这些结果表明，磷脂酰乙醇胺的层状相比磷脂酰胆碱的等效相更有序。在HII（倒六角形）相中，尽管增加了平移自由度，但脂质分子的包装受到高度限制，特别是在酰基链区域。
We report a simple new nuclear magnetic resonance (NMR) spectroscopic method to investigate order and dynamics in phospholipids in which inter-proton pair order parameters are derived by using high resolution13C cross-polarization/magic angle spinning (CP/MAS) NMR combined with1H dipolar echo preparation. The resulting two-dimensional NMR spectra permit determination of the motionally averaged interpair second moment for protons attached to each resolved13C site, from which the corresponding interpair order parameters can be deduced. A spin-lock mixing pulse before cross-polarization enables the detection of spin diffusion amongst the different regions of the lipid molecules. The method was applied to a variety of model membrane systems, including 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)/sterol and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)/sterol model membranes. The results agree well with previous studies using specifically deuterium labeled or perdeuterated phospholipid molecules. It was also found that efficient spin diffusion takes place within the phospholipid acyl chains, and between the glycerol backbone and choline headgroup of these molecules. The experiment was also applied to biosynthetically13C-labeled ergosterol incorporated into phosphatidylcholine bilayers. These results indicate highly restricted motions of both the sterol nucleus and the aliphatic side chain, and efficient spin exchange between these structurally dissimilar regions of the sterol molecule. Finally, studies were carried out in the lamellar liquid crystalline (Lα) and inverted hexagonal (HII) phases of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). These results indicated that phosphatidylethanolamine lamellar phases are more ordered than the equivalent phases of phosphatidylcholines. In the HII(inverted hexagonal) phase, despite the increased translational freedom, there is highly constrained packing of the lipid molecules, particularly in the acyl chain region.