Ferretti G, Tangorra A, Zolese G, Curatola G
Institute of Biochemistry, Faculty of Medicine, University of Ancona, Italy.
Membr Biochem. 1993 Jan-Mar;10(1):17-27. doi: 10.3109/09687689309150249.
Using static and dynamic fluorescence we studied the fluorescence properties of a phosphatidylcholine analog of 1,6-diphenyl-1,3,5-hexatriene (DPH-PC) incorporated in lymphocyte plasma membranes with respect to DPH and its cationic derivative 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), in order to study if phospholipid derivatives of DPH may be used to investigate structural and physicochemical properties of specific membrane lipid domains. DPH-PC and TMA-DPH showed similar fluorescence polarization values that were significantly higher with respect to DPH, suggesting a localization of the fluorescent portion of DPH-PC in a more ordered region of the membrane which was probably due to the elecrostatic interactions between phospholipid head-groups. The localization of the fluorescent moiety of DPH-PC near the membrane surface was also supported by the study of the fluorescence decay of the three probes using frequency-domain fluorometry. The main lifetime component of DPH-PC was rather similar to that of TMA-DPH (6.74 versus 6.24, ns) but considerably lower with respect to DPH (10.52 ns), in agreement with data obtained from exponential analysis. In lymphocyte membranes obtained from concanavalin A treated cells, a significant decrease of fluorescence polarization has been shown with DPH and its phosphatidylcholine derivative, but not with TMA-DPH. In liposomes obtained from total lipids extracted from lymphocyte membranes, a decrease of fluorescence polarization has been observed only with DPH. Our results suggest that DPH-PC localizes the fluorescent portion of its molecule in membrane microenvironments of different properties with respect to those probed by DPH and TMA-DPH. The use of DPH-phospholipid derivatives and other DPH-probes may represent an useful tool to study plasma membrane heterogeneity in biological membranes.
我们使用静态和动态荧光研究了掺入淋巴细胞质膜中的1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）的磷脂酰胆碱类似物（DPH - PC）相对于DPH及其阳离子衍生物1 - （4 - 三甲基铵苯基） - 6 - 苯基 - 1,3,5 - 己三烯（TMA - DPH）的荧光特性，以研究DPH的磷脂衍生物是否可用于研究特定膜脂结构域的结构和物理化学性质。DPH - PC和TMA - DPH显示出相似的荧光偏振值，相对于DPH显著更高，这表明DPH - PC的荧光部分定位于膜的更有序区域，这可能是由于磷脂头部基团之间的静电相互作用。使用频域荧光法对三种探针的荧光衰减进行研究也支持了DPH - PC荧光部分在膜表面附近的定位。DPH - PC的主要寿命成分与TMA - DPH相当相似（6.74对6.24，纳秒），但相对于DPH（10.52纳秒）则低得多，这与指数分析获得的数据一致。在用伴刀豆球蛋白A处理的细胞获得的淋巴细胞膜中，DPH及其磷脂酰胆碱衍生物的荧光偏振显著降低，但TMA - DPH没有。在从淋巴细胞膜中提取的总脂质获得的脂质体中，仅观察到DPH的荧光偏振降低。我们的结果表明，相对于由DPH和TMA - DPH探测的那些，DPH - PC将其分子的荧光部分定位于具有不同性质的膜微环境中。使用DPH - 磷脂衍生物和其他DPH - 探针可能是研究生物膜中质膜异质性的有用工具。
