Molecular organization of cholesterol, in polyunsaturated membranes: Microdomain formation
Molecular organization of cholesterol, in polyunsaturated membranes: Microdomain formation
复制标题
DOI：
10.1016/s0006-3495(02)75394-0
复制
发表时间：
2002-01-01
影响因子：
3.4
通讯作者：
Wassall, SR
中科院分区：
文献类型：
--
作者：
Brzustowicz, MR;Cherezov, V;Wassall, SR
采用固体H-2 NMR和低广角x射线衍射（XRD）研究了胆固醇在由1,2-二叠四烯酰基磷脂酰胆碱（20:4-20:4PC）、1-硬脂酰-2-花生四烯酰基磷脂酰胆碱（18:0-20:4PC）和20:4-20:4PC/18:0-20:4PC （1/1 mol）组成的磷脂双层中的分子结构。根据[3 α - h -2(1)]胆固醇嵌入膜中并作为固体相分离而形成的明显的四极性粉末模式，测定了在20:4-20:4PC中的溶解度chi(chol)(NMR) = 17 +/- 2 mol%，倾斜角α (o) =:25 +/- 1度。在18:0-20:4PC中对应的值为chi(chol)（NMR）大于等于50 mol%， α (o) = 16 +/- 1度。在20:4-20:4PC和18:0-20:4PC中，用XRD测定的胆固醇溶解度为chi(chol)(XRD) = 15 +/- 2 mol%, chi(chol)(XRD) = 49 +/- 1 mol%。XRD实验表明固体甾醇为单水晶体，可能存在于双分子层外。在混合的20:4-20:4PC/18:0-20:4PC （1/1 mol）膜中加入等摩尔[3 α -H-2(1)]胆固醇的H-2核磁共振谱与胆固醇在20:4-20:4PC和18:0-20:4PC微畴中的分离一致
The molecular organization of cholesterol, in phospholipid bilayers composed of 1,2-diarachidonylphosphatidylcholine (20:4-20:4PC), 1-stearoyl-2-arachidonylphosphatidylcholine (18:0-20:4PC), and 20:4-20:4PC/18:0-20:4PC (1/1 mol) was investigated by solid-state H-2 NMR and by low- and wide-angle x-ray diffraction (XRD). On the basis of distinct quadrupolar powder patterns arising from [3alpha-H-2(1)]cholesterol intercalated into the membrane and phase separated as solid, solubility chi(chol)(NMR) = 17 +/- 2 mol% and tilt angle alpha(o) = :25 +/- 1degrees in 20:4-20:4PC were determined. The corresponding values in 18:0-20:4PC were chi(chol)(NMR) greater than or equal to 50 mol% and alpha(o) = 16 +/- 1degrees. Cholesterol solubility determined by XRD was chi(chol)(XRD) = 15 +/- 2 mol% and chi(chol)(XRD) = 49 +/- 1 mol% for 20:4-20:4PC and 18:0-20:4PC, respectively. XRD experiments show that the solid sterol is monohydrate crystals presumably residing outside the bilayer. The H-2 NMR spectrum for equimolar [3alpha-H-2(1)]cholesterol added to mixed 20:4-20:4PC/18:0-20:4PC (1/1 mol) membranes is, consistent with segregation of cholesterol into 20:4-20: 4PC and 18:0-20:4PC microdomains of