Lateral pressure dependence of the phospholipid transmembrane diffusion rate in planar-supported lipid bilayers
Lateral pressure dependence of the phospholipid transmembrane diffusion rate in planar-supported lipid bilayers
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DOI：
10.1529/biophysj.107.118976
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发表时间：
2008-07-01
影响因子：
3.4
通讯作者：
Conboy, John C.
中科院分区：
文献类型：
--
作者：
Anglin, Timothy C.;Conboy, John C.
通过和频振动光谱研究了 1,2-二棕榈酰-sn-甘油-3-磷酸胆碱 (DPPC) 触发器动力学对磷脂双层中侧膜压力的依赖性。使用 Langmuir-Blodgett/Langmuir-Schaeffer 技术在熔融二氧化硅载体上制备平面支撑的脂质双层，该技术可以精确控制膜的侧表面压力和填充密度。脂质双层沉积压力在 28 至 42 mN/m 之间变化。在37℃下通过和频振动光谱测量了这些膜中脂质翻转的动力学。对于分别在28 mN/m和42 mN/m下制备的膜，测量了脂质易位速率常数的数量级差异（10.9 x 10(-4) s(-1)至1.03 x 10(-4) s(-1)）。这种速率变化是由于双层脂质堆积密度仅发生 7.4% 的变化所致。根据观察到的动力学，在 37 摄氏度下，无蛋白质 DPPC 平面支持的脂质双层中天然磷脂触发器的激活面积确定为 73 +/- 12 埃 (2)/分子。讨论了观察到的激活面积的意义以及该技术在磷脂触发器研究中的潜在未来应用。
The dependence of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) flip-flop kinetics on the lateral membrane pressure in a phospholipid bilayer was investigated by sum-frequency vibrational spectroscopy. Planar-supported lipid bilayers were prepared on fused silica supports using the Langmuir-Blodgett/Langmuir-Schaeffer technique, which allows precise control over the lateral surface pressure and packing density of the membrane. The lipid bilayer deposition pressure was varied from 28 to 42 mN/m. The kinetics of lipid flip-flop in these membranes was measured by sum-frequency vibrational spectroscopy at 37 degrees C. An order-of-magnitude difference in the rate constant for lipid translocation (10.9 x 10(-4) s(-1) to 1.03 x 10(-4) s(-1)) was measured for membranes prepared at 28 mN/m and 42 mN/m, respectively. This change in rate results from only a 7.4% change in the packing density of the lipids in the bilayer. From the observed kinetics, the area of activation for native phospholipid flip-flop in a protein-free DPPC planar-supported lipid bilayer was determined to be 73 +/- 12 angstrom(2)/molecule at 37 degrees C. Significance of the observed activation area and potential future applications of the technique to the study of phospholipid flip-flop are discussed.