Sjölund M, Lindblom G, Rilfors L, Arvidson G
Department of Physical Chemistry, University of Umeå, Sweden.
Biophys J. 1987 Aug;52(2):145-53. doi: 10.1016/S0006-3495(87)83202-2.
The system dioleoylphosphatidylcholine (DOPC)-n-dodecane-2H2O was investigated with different nuclear magnetic resonance (NMR) techniques: (a) a tentative phase diagram was determined by 2H- and 31P-NMR, (b) translational diffusion coefficients were determined for the three components with the pulsed magnetic field gradient NMR technique, and (c) order parameters for perdeuterated n-dodecane were obtained by 2H-NMR. n-Dodecane induces the formation of reversed hexagonal (HII) phases at low and high water concentrations, and cubic phases at low water contents. The translational diffusion coefficients of n-dodecane in a cubic phase with 6 mol water per mol DOPC, and in an HII phase with 48 mol water per mol DOPC, were just approximately 2.5 times lower than in pure dodecane. Perdeuterated dodecane gave large quadrupole splittings in a lamellar phase, much smaller in an HII phase at low water contents, and a narrow single peak in an HII phase at high water contents. This latter observation indicates that a large fraction of the dodecane molecules is located in separate regions between the water cylinders. Our results support the model given by Gruner concerning the aggregation of membrane lipids in the presence of hydrophobic molecules.
采用不同的核磁共振（NMR）技术对二油酰磷脂酰胆碱（DOPC）-正十二烷-2H₂O体系进行了研究：（a）通过²H-NMR和³¹P-NMR确定了初步的相图；（b）用脉冲磁场梯度NMR技术测定了三种组分的平移扩散系数；（c）通过²H-NMR获得了全氘代正十二烷的序参量。正十二烷在低水浓度和高水浓度下诱导形成反相六角（HII）相，在低含水量下诱导形成立方相。在每摩尔DOPC含6摩尔水的立方相中以及每摩尔DOPC含48摩尔水的HII相中，正十二烷的平移扩散系数仅比纯十二烷中的平移扩散系数低约2.5倍。全氘代十二烷在层状相中给出较大的四极分裂，在低含水量的HII相中要小得多，而在高含水量的HII相中给出一个窄的单峰。后一观察结果表明，大部分十二烷分子位于水柱之间的独立区域。我们的结果支持Gruner给出的关于在疏水分子存在下膜脂聚集的模型。
