Membrane permeabilization induced by Triton X-100: The role of membrane phase state and edge tension
Membrane permeabilization induced by Triton X-100: The role of membrane phase state and edge tension
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DOI：
10.1016/j.chemphyslip.2016.11.009
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发表时间：
2017-01-01
影响因子：
3.4
通讯作者：
Riske, Karin A.
中科院分区：
文献类型：
--
作者：
Mattei, Bruno;Lira, Rafael B.;Riske, Karin A.
去污剂广泛用于溶解和分离生物膜组分。因此，它是相关的研究和理解的机制细节的基础上，使用仿生系统的洗涤剂-脂质相互作用。在这里，我们详细研究了膜透化过程和由亚溶解浓度的清洁剂Triton X-100（TX-100）在由棕榈酰油酰磷脂酰胆碱（POPC）、鞘磷脂（SM）组成的双层中诱导的孔的性质。这些磷脂与30mol%胆固醇（chol）的二元混合物。使用荧光猝灭测定来评价在增加浓度的TX-100存在下大单层囊泡（LUV）的渗透性。采用共聚焦显微镜观察和量化巨大单层囊泡（GUV）在TX-100存在下对两种不同尺寸的荧光染料的渗透性。两种方法均表明，POPC、POPC/chol和SM膜在特定TX-100浓度下变得完全可渗透，然后在较高去污剂浓度下完全（POPC和SM）和部分（POPC/chol）溶解。共聚焦显微镜实验表明，孔的打开作为一个明确的事件发生，并且对于POPC和POPC/胆固醇，孔最初对小探针具有选择性，然后生长并允许较大的染料通过。另一方面，不溶性SM/chol膜仅表现出轻度TX-100诱导的透化。液相的膜边缘张力由GUV中电脉冲引起的大孔的闭合率测量。膜边缘张力被证明是敏感的膜组成，并在TX-100的存在下降低。我们认为，在临界膜边缘张力以下会发生广泛的透化，最终在部分和完全可溶的组合物中达到该张力，但在不溶的混合物中不会达到该张力。(C)2016爱思唯尔爱尔兰有限公司版权所有。
Detergents are widely used to solubilize and separate biomembrane components. It is therefore relevant to study and understand the mechanistic details underlying detergent-lipid interactions using biomimetic systems. Here, we have investigated in detail the process of membrane permeabilization and the nature of pores induced by sub-solubilizing concentrations of the detergent Triton X-100 (TX-100) in bilayers composed of palmitoyl oleoyl phosphatidylcholine (POPC), sphingomyelin (SM) and binary mixtures of these phospholipids with 30 mol% cholesterol (chol). A fluorescence quenching assay was used to evaluate the permeability of large unilamellar vesicles (LUVs) in the presence of increasing concentrations of TX-100. Confocal microscopy was employed to visualize and quantify the permeability of giant unilamellar vesicles (GUVs) to two fluorescent dyes of different sizes in the presence of TX-100. Both methods showed that POPC, POPC/chol and SM membranes become fully permeable at a specific TX-100 concentration, followed by complete (POPC and SM) and partial (POPC/chol) solubilization at a higher detergent concentration. The confocal microscopy experiments revealed that opening of pores occurs as a well-defined event and that for POPC and POPC/chol the pores were initially selective to the small probe and then grew and allowed passage of the larger dye as well. On the other hand, the insoluble SM/chol membranes exhibited only a mild TX-100-induced permeabilization. The membrane edge tension of the liquid phases was measured from the closure rate of macropores induced by electric pulses in GUVs. Membrane edge tension was shown to be sensitive to membrane composition and to decrease in the presence of TX-100. We propose that extensive permeabilization occurs below a critical membrane edge tension, which is eventually reached in the partially and fully soluble compositions, but not in the insoluble mixture. (C) 2016 Elsevier Ireland Ltd. All rights reserved.