Bondar O P, Pivovarenko V G, Rowe E S
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103, USA.
Biochim Biophys Acta. 1998 Feb 2;1369(1):119-30. doi: 10.1016/s0005-2736(97)00218-6.
Two flavonols, 3-hydroxy-4'-dimethylaminoflavone (FME) and 3-hydroxy-4'-(15-azacrown-5) flavone (FRC) have been investigated as new fluorescence probes for studying the formation of the interdigitated gel phase in lipid bilayers. The formation of the interdigitated gel phase in the saturated symmetrical phosphatidylcholines (PCs) and phosphatidylethanol (Peth) in the presence of ethanol has been well studied. The present study examines the behavior of these new probes in PC-ethanol and Peth-ethanol systems, as well as in PC-cholesterol and Peth-cholesterol vesicles. The present results demonstrate that both flavonols give distinctively different spectra in interdigitated lipid compared to non-interdigitated lipids, when examined in lipids in which the interdigitation behavior is known. This makes them useful for determinations of the structural state of unknown lipids, and for following the transitions between interdigitated and non-interdigitated phases. However, in the presence of cholesterol, only FCR gave appropriate indications of interdigitation. The results with FME in the presence of cholesterol were not consistent with the known behavior of the lipids examined; instead, FME appears to be located preferentially in the cholesterol-rich non-interdigitated regions of the bilayer.
两种黄酮醇，3-羟基-4'-二甲基氨基黄酮（FME）和3-羟基-4'-(15-氮杂冠-5)黄酮（FRC），已被作为新型荧光探针进行研究，用于研究脂质双层中叉指状凝胶相的形成。在乙醇存在下，饱和对称磷脂酰胆碱（PCs）和磷脂酰乙醇（Peth）中叉指状凝胶相的形成已得到充分研究。本研究考察了这些新型探针在PC-乙醇和Peth-乙醇体系中，以及在PC-胆固醇和Peth-胆固醇囊泡中的行为。目前的结果表明，当在已知叉指行为的脂质中进行检测时，与非叉指脂质相比，这两种黄酮醇在叉指脂质中给出的光谱明显不同。这使得它们可用于测定未知脂质的结构状态，以及追踪叉指相和非叉指相之间的转变。然而，在胆固醇存在的情况下，只有FCR给出了叉指的适当指示。在胆固醇存在下FME的结果与所检测脂质的已知行为不一致；相反，FME似乎优先位于双层中富含胆固醇的非叉指区域。
