荧光二芘脂质的分子内激基复合物动力学：1. 二肉豆蔻酰磷脂酰胆碱/胆固醇膜
Intramolecular excimer kinetics of fluorescent dipyrenyl lipids: 1. DMPC/cholesterol membranes.
作者信息
Cheng K H, Ruymgaart L, Liu L I, Somerharju P, Sugar I P
机构信息
Department of Physics, Texas Tech University, Lubbock 79409.
出版信息
Biophys J. 1994 Aug;67(2):902-13. doi: 10.1016/S0006-3495(94)80552-1.
The intramolecular dynamics of the excimer forming dipyrenyl lipids (DipynPC) of different chain lengths (n) in ethanol and in dimyristoylphosphatidycholine (DMPC) membranes was investigated by the use of frequency-domain fluorescence intensity decay technique. Based on a 3-state model, the extent of aggregation and rotational rate of the two intralipid pyrene moieties in the dipyrenyl lipids were estimated from the frequency-domain data. In ethanol (20 degrees C), the rotational rate for DipynPC increased progressively as n was varied from 4 to 12. At the gel (L beta)-to-liquid crystalline (L alpha) phase transition of DMPC (approximately 23 degrees C), the rotational rate increased and aggregation decreased significantly for Dipy10PC, whereas only the rotational rate was changed for Dipy4PC. In the presence of 30 mol% cholesterol, significant increases in both the rotational rate and aggregation were observed for Dipy10PC in both L beta and L alpha phases. However, for the case of Dipy4PC, an increase in the rotational rate but a decrease in the aggregation were noticed only in the L beta phase, and no similar changes were detected in the L alpha phase. Our results indicate differential effects of cholesterol on the conformational dynamics of acyl chains at different depths of the membranes.
通过频域荧光强度衰减技术，研究了不同链长（n）的准分子形成二芘基脂质（DipynPC）在乙醇和二肉豆蔻酰磷脂酰胆碱（DMPC）膜中的分子内动力学。基于三态模型，从频域数据估计二芘基脂质中两个脂质内芘部分的聚集程度和旋转速率。在乙醇（20℃）中，随着n从4变化到12，DipynPC的旋转速率逐渐增加。在DMPC的凝胶（Lβ）到液晶（Lα）相转变（约23℃）时，Dipy10PC的旋转速率增加而聚集显著减少，而对于Dipy4PC仅旋转速率发生变化。在存在30mol%胆固醇的情况下，Dipy10PC在Lβ和Lα相中旋转速率和聚集均显著增加。然而，对于Dipy4PC的情况，仅在Lβ相中观察到旋转速率增加但聚集减少，而在Lα相中未检测到类似变化。我们的结果表明胆固醇对膜不同深度处酰基链构象动力学有不同影响。
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