Rand R P, Luzzati V
Biophys J. 1968 Jan;8(1):125-37. doi: 10.1016/S0006-3495(68)86479-3.
Lipids, carefully extracted from fresh human erythrocytes, form liquid-crystalline structures in water. A phase diagram of this system was constructed, characterizing, by X-ray diffraction, the structures which form as a function of concentration of lipid and temperature. One extended range of concentration of the phase diagram, in which a single lamellar phase exists, permitted further analysis of the diffraction data. This phase consists of lipid layers of constant thickness separated by water layers of varying thickness according to the water content of the system. The distribution of the electron density is precisely analyzed and the amplitude of the reflections is, at all concentrations, proportional to the Fourier Transform of an isolated lipid layer. This shows that the lipid layer is filled with the hydro-carbon chains of the phospholipids and is covered on both sides by their hydrophilic groups. Cholesterol, present in high concentration in erythrocyte membranes, is located so that part of its steroid nucleus is between the polar groups of the phospholipid molecules while the rest of the molecule extends into the inner hydrocarbon layer.
从新鲜人体红细胞中精心提取的脂质，在水中形成液晶结构。构建了该系统的相图，通过X射线衍射表征了随着脂质浓度和温度变化而形成的结构。相图中存在单一层状相的一个浓度扩展范围，使得能够对衍射数据进行进一步分析。该相由厚度恒定的脂质层组成，这些脂质层被根据系统含水量而厚度不同的水层隔开。精确分析了电子密度的分布，并且在所有浓度下，反射的振幅都与孤立脂质层的傅里叶变换成正比。这表明脂质层充满了磷脂的烃链，并且在两侧都被其亲水基团覆盖。红细胞膜中高浓度存在的胆固醇的定位方式是，其部分甾体核位于磷脂分子的极性基团之间，而分子的其余部分延伸到内部烃层中。
