Effect of hydrostatic pressure on water penetration and rotational dynamics in phospholipid-cholesterol bilayers
Effect of hydrostatic pressure on water penetration and rotational dynamics in phospholipid-cholesterol bilayers
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DOI：
10.1016/s0006-3495(97)78773-3
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发表时间：
1997-03-01
影响因子：
3.4
通讯作者：
Gratton, E
中科院分区：
文献类型：
--
作者：
Bernsdorff, C;Wolf, A;Gratton, E
用时间分辨荧光光谱法研究了1，2-二棕榈酰-sn-甘油-3-磷酸胆碱（DPPC）和1-棕榈酰-2-油酰-sn-甘油-3-磷酸胆碱（POPC）胆固醇囊泡在1500 bar压力下的脂质双层水合作用、平均序参量和旋转动力学。而脂质头基和界面区域中的水合程度是使用探针1- 10从荧光寿命数据评估的。（4-三甲基铵-苯基）-6-苯基-1，3，5-己三烯（TMA-DPH），上酰基链区域中的相应信息由其对和3-（二苯基己三烯基）丙基-三甲基铵（TMAP-DPH）。寿命数据表明DPPC双层的界面水合水平高于POPC双层，但两种双层系统的链间水合没有显著差异，胆固醇的添加水平为30至50摩尔%，与施加几百至1000的静水压力相比，DPPC对增加双层界面区域的疏水性具有更大的影响酒吧虽然在相应的系统POPC/30 mol%胆固醇中观察到相同的趋势，但观察到的影响明显不太明显。而旋转相关时间的荧光团减少通过压力诱导的液晶凝胶相变的DPPC，摆动扩散系数基本保持不变，摆动扩散常数的两个荧光团的变化显着时，纳入30摩尔%的胆固醇，并增加在较高的压力，也在POPC/30摩尔%的胆固醇的情况下。所观察到的效果进行了讨论的荧光团的旋转特性和相态的脂质混合物的变化。结果表明，胆固醇能够调节由不同磷脂组分组成的膜的结构和动力学性质，并有效地调节膜的运动自由度和疏水性，从而使它们能够承受甚至剧烈的环境条件变化，例如高的外部静水压力。
The effect of high hydrostatic pressure on the lipid bilayer hydration, the mean order parameter, and rotational dynamics of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) cholesterol vesicles has been studied by time-resolved fluorescence spectroscopy up to 1500 bar, Whereas the degree of hydration in the lipid headgroup and interfacial region was assessed from fluorescence lifetime data using the probe 1-(4-trimethylammonium-phenyl)-6-phenyl-,3,5-hexatriene (TMA-DPH), the corresponding information in the upper acyl chain region was estimated from its effect on the fluorescence lifetime of and 3-(diphenylhexatrienyl)propyl-trimethylammonium (TMAP-DPH). The lifetime data indicate a greater level of interfacial hydration for DPPC bilayers than for POPC bilayers, but there is no marked difference in interchain hydration of the two bilayer systems, The addition of cholesterol at levels from 30 to 50 mol% to DPPC has a greater effect on the increase of hydrophobicity in the interfacial region of the bilayer than the application of hydrostatic pressure of several hundred to 1000 bar. Although the same trend is observed in the corresponding system, POPC/30 mol% cholesterol, the observed effects are markedly less pronounced. Whereas the rotational correlation times of the fluorophores decrease in passing the pressure-induced liquid-crystalline to gel phase transition of DPPC, the wobbling diffusion coefficient remains essentially unchanged, The wobbling diffusion constant of the two fluorophores changes markedly upon incorporation of 30 mol% cholesterol, and increases at higher pressures, also in the case of POPC/30 mol% cholesterol. The observed effects are discussed in terms of changes in the rotational characteristics of the fluorophores and the phase-state of the lipid mixture. The results demonstrate the ability of cholesterol to adjust the structural and dynamic properties of membranes composed of different phospholipid components, and to efficiently regulate the motional freedom and hydrophobicity of membranes, so that they can withstand even drastic changes in environmental conditions, such as high external hydrostatic pressure.