Use of laurdan fluorescence intensity and polarization to distinguish between changes in membrane fluidity and phospholipid order
Use of laurdan fluorescence intensity and polarization to distinguish between changes in membrane fluidity and phospholipid order
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DOI：
10.1016/s0005-2736(02)00514-x
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发表时间：
2002-09-20
影响因子：
3.4
通讯作者：
Bell, JD
中科院分区：
文献类型：
--
作者：
Harris, FM;Best, KB;Bell, JD
Laurdan是一种荧光探针，它通过对双层中环境的极性敏感来检测膜相性质的变化。膜水含量的变化引起Laurdan发射光谱的变化，通过计算广义极化(GP)来量化。我们通过检测Laurdan GP的温度依赖性和二棕榈酰磷脂酰胆碱(DPPC)囊泡的荧光各向异性，验证了Laurdan荧光能否用于区分磷脂有序性的差异和膜流动性的变化。Laurdan GP值从0.7降至-0.14，各向异性从0.25降至0.12，从固体有序相向液体无序相转变。在膜中加入不同数量的胆固醇以产生液体有序相会导致Laurdan GR检测到的表观熔化温度升高，相反，胆固醇降低了根据各向异性测量估计的表观熔化温度。根据这些结果，Laurdan各向异性检测到了膜流动性的变化，而Laurdan GP检测到了磷脂顺序的变化。因此，同一荧光探针可以通过比较荧光发射和各向异性测量的结果来区分扰动对膜有序性和流动性的影响。(C)2002 Elsevier Science B.V.保留所有权利。
Laurdan is a fluorescent probe that detects changes in membrane phase properties through its sensitivity to the polarity of its environment in the bilayer. Variations in membrane water content cause shifts in the laurdan emission spectrum, which are quantified by calculating the generalized polarization (GP). We tested whether laurdan fluorescence could be used to distinguish differences in phospholipid order from changes in membrane fluidity by examining the temperature dependence of laurdan GP and fluorescence anisotropy in dipalmitoylphosphatidylcholine (DPPC) vesicles. The phase transition from the solid ordered phase to the liquid disordered phase was observed as a decrease in laurdan GP values from 0.7 to -0.14 and a reduction in anisotropy from 0.25 to 0.12. Inclusion of various amounts of cholesterol in the membranes to generate a liquid ordered phase caused an increase in the apparent melting temperature detected by laurdan GR In contrast, cholesterol decreased the apparent melting temperature estimated from anisotropy measurements. Based on these results, it appeared that laurdan anisotropy detected changes in membrane fluidity while laurdan GP sensed changes in phospholipid order. Thus, the same fluorescent probe can be used to distinguish effects of perturbations on membrane order and fluidity by comparing the results of fluorescence emission and anisotropy measurements. (C) 2002 Elsevier Science B.V. All rights reserved.