COMBINED INFLUENCE OF CHOLESTEROL AND SYNTHETIC AMPHIPHILLIC PEPTIDES UPON BILAYER THICKNESS IN MODEL MEMBRANES
COMBINED INFLUENCE OF CHOLESTEROL AND SYNTHETIC AMPHIPHILLIC PEPTIDES UPON BILAYER THICKNESS IN MODEL MEMBRANES
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DOI：
10.1016/s0006-3495(92)81926-4
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发表时间：
1992-05-01
影响因子：
3.4
通讯作者：
BLOOM, M
中科院分区：
文献类型：
--
作者：
NEZIL, FA;BLOOM, M
氘（H-2）NMR用于研究当胆固醇和/或合成的两亲性多肽被添加到液晶（流体）相中的氘代POPC脂质双层膜时的双层疏水厚度和机械性质。平滑的酰基链取向顺序配置文件被用来计算双层疏水厚度。在25 ℃下向POPC中加入30 mol%胆固醇使双层厚度从2.58 nm增加到2.99 nm。选择肽以跨越双层，疏水性肽长度和膜疏水性厚度之间或多或少不匹配。纯脂质双层的平均厚度仅在大错配的情况下在添加肽时被显著扰动，当肽疏水长度大于（小于）纯双层的疏水长度时增加（减少），与蛋白质脂质相互作用的“床垫”模型一致（Mackitsen，0. G.，和M.布鲁姆1984. Biophys. J 46：141-153）。实验结果也被用来检查的多肽和胆固醇的取向顺序配置文件和膜的厚度膨胀率的综合影响。提出了一个详细的模型的POPC和胆固醇分子的双层中的空间分布，以调和这些测量的一般功能与微机械测量的面积膨胀率在密切相关的系统。提出了测试该模型的实验。
Deuterium (H-2) NMR was used to study bilayer hydrophobic thickness and mechanical properties when cholesterol and/or synthetic amphiphilic polypeptides were added to deuterated POPC lipid bilayer membranes in the liquid-crystalline (fluid) phase. Smoothed acyl chain orientational order profiles were used to calculate bilayer hydrophobic thickness. Addition of 30 mol% cholesterol to POPC at 25-degrees-C increased the bilayer thickness from 2.58 to 2.99 nm. The peptides were chosen to span the bilayers with more or less mismatch between the hydrophobic peptide length and membrane hydrophobic thickness. The average thickness of the pure lipid bilayers was significantly perturbed upon addition of peptide only in cases of large mismatch, being increased (decreased) when the peptide hydrophobic length was greater (less) than that of the pure bilayer, consistent with the "mattress" model of protein lipid interactions (Mouritsen, O.G., and M. Bloom. 1984. Biophys. J 46:141-153). The experimental results were also used to examine the combined influence of the polypeptides and cholesterol on the orientational order profile and thickness expansivity of the membranes. A detailed model for the spatial distribution of POPC and cholesterol molecules in the bilayers was proposed to reconcile the general features of these measurements with micromechanical measurements of area expansivity in closely related systems. Experiments to test the model were proposed.