Martin C E, Foyt D C
Biochemistry. 1978 Aug 22;17(17):3587-91. doi: 10.1021/bi00610a026.
Measurement of the time-resolved fluorescence depolarization of 1,6-diphenylhexatriene (DPH) in artificial bilayers of microsomal membrane lipids from Tetrahymena gives detailed information concerning the molecular motion of this probe and fluid properties of the membrane lipids which are obscured with steady-state methods. The rotational motion of DPH in these lipids from cells acclimated to 15 and 39.5 degrees C growth temperatures was anisotropic, which agrees with recent time-resolved studies of this probe in synthetic phospholipid systems. Evaluation of DPH polarization data obtained from these lipid fractions at their respective growth temperatures showed differences in physical properties which suggest that "viscosity", per se, of the microsomal lipids is not a strictly regulated as it is in prokaryotic systems. Rotational relaxation of DPH in 39.5 degrees C microsomal lipids measured at 15 degrees C is more complex than that of either lipid fraction measured at its actual growth temperature, suggesting that the probe has partitioned into two dissimilar environments within the bilayer. Similar effects are observed in the microsomes of 39.5 degrees C cells by freeze-fracture electron microscopy following rapid cooling to 15 degrees C. Under these conditions, two distinct regions are observed on the fracture faces, suggesting a correlation between lipid phase changes and alterations in membrane structure.
对来自四膜虫微粒体膜脂人工双层中1,6 - 二苯基己三烯（DPH）的时间分辨荧光去极化进行测量，可提供有关该探针分子运动以及膜脂流体性质的详细信息，而这些信息在稳态方法中会被掩盖。在适应15摄氏度和39.5摄氏度生长温度的细胞的这些脂类中，DPH的旋转运动是各向异性的这与该探针在合成磷脂系统中的近期时间分辨研究结果一致。对在各自生长温度下从这些脂质组分获得的DPH极化数据的评估表明，物理性质存在差异，这表明微粒体脂质的“粘度”本身并不像在原核系统中那样受到严格调控。在15摄氏度下测量的39.5摄氏度微粒体脂质中DPH的旋转弛豫比在其实际生长温度下测量的任何一种脂质组分都更复杂，这表明该探针已在双层内分配到两个不同的环境中。在快速冷却至15摄氏度后，通过冷冻断裂电子显微镜在39.5摄氏度细胞的微粒体中也观察到了类似的效应。在这些条件下，在断裂面上观察到两个不同的区域，这表明脂质相变与膜结构改变之间存在相关性。
