Influence of molecular packing and phospholipid type on rates of cholesterol exchange.
Influence of molecular packing and phospholipid type on rates of cholesterol exchange.
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DOI：
10.1021/bi00409a044
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发表时间：
1986-05
期刊：
影响因子：
2.9
通讯作者：
S. Lund-Katz;H. Laboda;L. McLean;M. Phillips
中科院分区：
文献类型：
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作者：
S. Lund-Katz;H. Laboda;L. McLean;M. Phillips
已测定了含有溶解在不同磷脂双层中的胆固醇的小单层囊泡的[14C]胆固醇转移速率，以检查磷脂-胆固醇相互作用对胆固醇从脂质-水界面解吸速率的影响。磷脂包括不饱和磷脂酰胆碱 (PC's)（蛋 PC、二油酰基-PC 和大豆 PC）、饱和 PC（二肉豆蔻酰基-PC 和二棕榈酰基-PC）和鞘磷脂 (SM's)（蛋基 SM、牛脑 SM 和 N-棕榈酰基-SM）。在 37 摄氏度下，对于含有 10 mol% 胆固醇的囊泡，不饱和 PC、饱和 PC 和 SM 的交换半衰期分别约为 1、13 和 80 小时。为了探究双层中分子堆积的差异如何导致胆固醇解吸速率常数的顺序为不饱和PC大于饱和PC大于SM，使用核磁共振（NMR）和单层方法来评估胆固醇的物理状态以及与磷脂的相互作用。 [4-13C]胆固醇的NMR弛豫参数显示上述双层中的分子动力学没有差异。胆固醇和上述磷脂混合单层的表面压力（pi）-分子面积等温线表明，SM 横向堆积密度大于具有相同酰基链饱和度和长度的 PC（例如，在 pi = 5 mN/m 时，两个单层处于相同的物理状态，二棕榈酰-PC 和棕榈酰-SM 分别占据 87 和 81 个 A2/分子）。（摘要截断） 250 字）
The rates of [14C]cholesterol transfer from small unilamellar vesicles containing cholesterol dissolved in bilayers of different phospholipids have been determined to examine the influence of phospholipid-cholesterol interactions on the rate of cholesterol desorption from the lipid-water interface. The phospholipids included unsaturated phosphatidylcholines (PC's) (egg PC, dioleoyl-PC, and soybean PC), saturated PC (dimyristoyl-PC and dipalmitoyl-PC), and sphingomyelins (SM's) (egg SM, bovine brain SM, and N-palmitoyl-SM). At 37 degrees C, for vesicles containing 10 mol% cholesterol, the half-times for exchange are about 1, 13, and 80 h, respectively, for unsaturated PC, saturated PC, and SM. In order to probe how differences in molecular packing in the bilayers cause the rate constants for cholesterol desorption to be in the order unsaturated PC greater than saturated PC greater than SM, nuclear magnetic resonance (NMR) and monolayer methods were used to evaluate the cholesterol physical state and interactions with phospholipid. The NMR relaxation parameters for [4-13C]cholesterol reveal no differences in molecular dynamics in the above bilayers. Surface pressure (pi)-molecular area isotherms for mixed monolayers of cholesterol and the above phospholipids reveal that SM lateral packing density is greater than that of the PC with the same acyl chain saturation and length (e.g., at pi = 5 mN/m, where both monolayers are in the same physical state, dipalmitoyl-PC and palmitoyl-SM occupy 87 and 81 A2/molecule, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)