Montez B, Oldfield E, Urbina J A, Pekerar S, Husted C, Patterson J
Department of Chemistry, University of Illinois at Urbana-Champaign 61801.
Biochim Biophys Acta. 1993 Nov 7;1152(2):314-8. doi: 10.1016/0005-2736(93)90263-y.
We report the carbon-13 'magic-angle' sample-spinning nuclear magnetic resonance (NMR) spectra of several lipid-water systems, under a variety of radiofrequency excitation conditions. Our results show that complex lipid or membrane spectra can be greatly simplified by using 'spectral editing' techniques. For example, in a 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC)-water mesophase, the glycerol (C-1, C-2 and C-3) carbons are readily distinguished from the headgroup C alpha, C beta and C gamma carbons, on the basis of their mix-time behavior in a cross-polarization (CP) experiment, while in the more complex DMPC/cholesterol-water system, many of the more rigid cholesterol carbon resonances can be edited from the phospholipid peaks. In very complex systems, such as human myelin membranes, editing permits the unambiguous observation of the mobile lipid headgroup carbon resonances, as well as the much more rigid sterol ring carbons. We also report the observation of a large differential CP due to C-H vector 'magic-angle' orientational effects in the DMPC/desipramine system. Thus, both motional or orientational reduction of the C-H dipolar interaction can lead to considerable simplifications of complex membrane spectra, and are of interest from both spectral assignment and membrane dynamics aspects.
我们报告了在多种射频激发条件下，几种脂质 - 水体系的碳 - 13 “魔角” 样品旋转核磁共振（NMR）光谱。我们的结果表明，通过使用 “光谱编辑” 技术，复杂的脂质或膜光谱可以大大简化。例如，在1,2 - 二肉豆蔻酰 - sn - 甘油 - 3 - 磷酸胆碱（DMPC） - 水中间相中，基于甘油（C - 1、C - 2和C - 3）碳在交叉极化（CP）实验中的混合时间行为，可以很容易地将其与头部基团的Cα、Cβ和Cγ碳区分开来。而在更复杂的DMPC / 胆固醇 - 水体系中，许多更刚性的胆固醇碳共振可以从磷脂峰中编辑出来。在非常复杂的体系中，如人髓鞘膜，编辑允许明确观察到可移动的脂质头部基团碳共振以及更刚性的甾醇环碳。我们还报告了在DMPC / 地昔帕明体系中，由于C - H矢量 “魔角” 取向效应而观察到的大的差异CP。因此，C - H偶极相互作用的运动或取向减弱都可以导致复杂膜光谱的显著简化，并且从光谱归属和膜动力学方面来看都很有意义。
