Ulmius J, Wennerström H, Lindblom G, Arvidson G
Biochim Biophys Acta. 1975 May 6;389(2):197-202. doi: 10.1016/0005-2736(75)90315-6.
Proton NMR spectra for gel and liquid crystalline samples, composed of dimyristoyl and/or dipalmitoyl lecithin, cholesterol and water, can be consistently interpreted in terms of mesophase symmetry and molecular diffusion according to a model proposed by Wennerstrom (Wennerstrom, H. (1973) Chem. Phys. Lett. 18, 41-44). It is shown by computer simulation that the characteristic "super-lorentzian" bandshape of the lamellar mesophase can be described by the superposition of three gaussian curves. The NMR signal of the gel phase can be simulated by the superposition of two gaussian curves with widths at half height of 2.5 kHz and 19 kHz. An upper limit of the lateral diffusion coefficient of the lecithin molecules in the gel phase is calculated to be about 5-10(-15) m-2/s. It is therefore concluded that the static intermolecular dipolar couplings average to zero in the lamellar mesophase. An estimation of the order parameter of the liquid crystalline phase is made from experimental data and a calculated "rigid lattice" linewidth. A two phase system is shown to exist in the temperature range 28-34 degrees C for a mesophase of a mixture of dimyristoyl and dipalmitoyl lecithin. The presence of cholesterol results in enhanced lateral diffusion of the lecithin molecules at temperatures below the Chapman transition point.
由二肉豆蔻酰和/或二棕榈酰卵磷脂、胆固醇和水组成的凝胶和液晶样品的质子核磁共振谱，可以根据温纳斯特伦提出的模型（温纳斯特伦，H.（1973年）《化学物理快报》18，41 - 44），依据中间相对称性和分子扩散进行一致的解释。计算机模拟表明，层状中间相的特征“超洛伦兹”带状形状可以用三条高斯曲线的叠加来描述。凝胶相的核磁共振信号可以通过半高宽为2.5千赫兹和19千赫兹的两条高斯曲线的叠加来模拟。计算得出凝胶相中卵磷脂分子横向扩散系数的上限约为5 - 10（-15）平方米/秒。因此得出结论，在层状中间相中静态分子间偶极耦合平均为零。根据实验数据和计算出的“刚性晶格”线宽对液晶相的序参数进行了估计。对于二肉豆蔻酰和二棕榈酰卵磷脂混合物的中间相，在28 - 34摄氏度的温度范围内显示存在两相系统。胆固醇的存在导致在低于查普曼转变点的温度下卵磷脂分子的横向扩散增强。
