Department of Chemical Engineering, University of Rhode Island, 16 Greenhouse Rd., Kingston, Rhode Island 02881, United States.
Langmuir. 2013 Aug 27;29(34):10817-23. doi: 10.1021/la400977h. Epub 2013 Aug 19.
Cellular adaptation to elevated alcohol concentration involves altering membrane lipid composition to counteract fluidization. However, few studies have examined the biophysical response of biologically relevant heterogeneous membranes. Lipid phase behavior, molecular packing, and elasticity have been examined by surface pressure-area (π-A) analysis in mixed monolayers composed of saturated dipalmitoylphosphatidylcholine (DPPC) and unsaturated dioleoylphosphatidylcholine (DOPC) as a function of DOPC and n-butanol concentration. n-Butanol partitioning into DPPC monolayers led to lipid expansion and increased elasticity. Greater lipid expansion occurred with increasing DOPC concentration, and a maximum was observed at equimolar DPPC:DOPC consistent with n-butanol partitioning between coexisting liquid expanded (LE, DOPC) phases and liquid condensed (LC, DPPC) domains. This led to distinct changes in the size and morphology of LC domains. In DOPC-rich monolayers the effect of n-butanol adsorption on π-A behavior was less pronounced due to DOPC tail kinking. These results point to the importance of lipid composition and phase coexistence on n-butanol partitioning and monolayer restructuring.
细胞对高浓度酒精的适应涉及改变膜脂组成以对抗流动性。然而，很少有研究检查生物相关的异质膜的生物物理响应。通过表面压力-面积（π-A）分析，在由饱和二棕榈酰磷脂酰胆碱（DPPC）和不饱和二油酰磷脂酰胆碱（DOPC）组成的混合单层中，研究了脂质相行为、分子堆积和弹性，作为 DOPC 和正丁醇浓度的函数。正丁醇分配到 DPPC 单层中导致脂质膨胀和弹性增加。随着 DOPC 浓度的增加，脂质膨胀更大，在 DPPC:DOPC 等摩尔比处观察到最大值，这与正丁醇在共存的液体膨胀（LE，DOPC）相和液体浓缩（LC，DPPC）域之间的分配一致。这导致 LC 域的大小和形态发生明显变化。在富含 DOPC 的单层中，由于 DOPC 尾部弯曲，正丁醇吸附对 π-A 行为的影响不太明显。这些结果表明脂质组成和相共存对正丁醇分配和单层重构的重要性。
