2-DIMENSIONAL PASSIVE RANDOM-WALK IN LIPID BILAYERS AND FLUID PATHWAYS IN BIOMEMBRANES
2-DIMENSIONAL PASSIVE RANDOM-WALK IN LIPID BILAYERS AND FLUID PATHWAYS IN BIOMEMBRANES
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DOI：
10.1007/bf01872892
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发表时间：
1979-01-01
影响因子：
2.4
通讯作者：
SACKMANN, E
中科院分区：
文献类型：
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作者：
GALLA, HJ;HARTMANN, W;SACKMANN, E
芘、芘癸酸和1-棕榈酰-2-芘癸酰-磷脂酰胆碱（芘卵磷脂）在脂质双分子层中的横向迁移率由准分子形成技术确定。该方法适用于不同链长和烃链饱和程度的卵磷脂囊泡。这些值与不同链长的头孢肽和不同ph值下双棕榈酰磷脂酸的结果进行了比较。用二维随机漫步的Montroll模型对结果进行了分析。得到了探针分子在脂质晶格内的跳频。这种脂质层运输测量的优点是它不涉及脂质晶格参数。饱和卵磷脂薄片中给定溶质分子的横向迁移率与烃链长度无关，而是温度的普遍函数。在不饱和二油基卵磷脂中，两相分子具有与饱和脂类相同大小的横向流动性。在不饱和卵磷脂中，芘的跳跃频率要大2倍。磷脂酰乙醇胺的跳跃频率约为。和卵磷脂中的一样。在磷脂酸层中，跳频取决于脂质和探针的头基团的电荷。胆固醇强烈地降低了流体层的跳跃频率。生物膜的横向迁移率与人工脂质双分子层相当。根据流体中扩散的自由体积模型对结果进行了讨论。结果与该模型的预测结果吻合较好。一个引人注目的结果是观察到芘和芘卵磷脂的跳频在二聚乙二醇-卵磷脂双层膜中的倾斜。倾斜角度为。= 17.度。估计。
The lateral mobility of pyrene, pyrenedecanoic acid, and 1-palmitoyl-2-pyrene decanoyl-phosphatidyl choline (pyrene lecithin) in lipid bilayers is determined by the excimer formation technique. This method is applied to vesicles of lecithins differing in chain length and in the degree of saturation of the hydrocarbon chains. These values are compared with results in cephalins of different chain length and in dipalmitoyl phosphatidic acid at variable pH. The influence of cholesterol is investigated. The results are analyzed in terms of the Montroll model of 2 dimensional random walk. The jump frequency of the probe molecule within the lipid lattice is obtained. The advantage of this measure of transport in lipid layers is that it does not involve lipid lattice parameters. The lateral mobility of a given solute molecule in lamellae of saturated lecithins is independent of hydrocarbon chain length and rather a universal function of temperature. In unsaturated dioleyl lecithin the amphiphatic molecules have lateral mobilities of the same size as in saturated lipids. The jump frequency of pyrene is by a factor of 2 larger in the unsaturated lecithin. The jump frequencies in phosphatidyl ethanolamines are .apprx. equal to those in lecithins. In phosphatidic acid layers the hopping frequencies depend on the charges of the head groups of both the lipids and the probes. Cholesterol strongly reduces the jump frequency in fluid layers. The lateral mobility in biological membranes is comparable to that in artificial lipid bilayer. The results are discussed in terms of the free volume model of diffusion in fluids. Good agreement with the predictions made from this model is found. A striking result is the observation of a tilt in dioleyl-lecithin bilayer membranes from the hopping frequencies of pyrene and pyrene lecithin. A tilt angle of .phi. = 17.degree. is estimated.