Ausili Alessio, Torrecillas Alejandro, Aranda Francisco, de Godos Ana, Sánchez-Bautista Sonia, Corbalán-García Senena, Gómez-Fernández Juan C
Departamento de Bioquímica y Biología Molecular (A), Facultad de Veterinaria, Universidad de Murcia, Apartado de Correos 4021, Murcia, Spain.
J Phys Chem B. 2008 Oct 9;112(40):12696-702. doi: 10.1021/jp802215s. Epub 2008 Sep 17.
The interaction between oxidized (ubiquinone-10) and reduced (ubiquinol-10) coenzyme Q 10 with dimyristoylphosphatidylcholine has been examined by differential scanning microcalorimetry, X-ray diffraction, infrared spectroscopy, and (2)H NMR. Microcalorimetry experiments showed that ubiquinol-10 perturbed considerably more the phase transition of the phospholipids than ubiquinone-10, both forms giving rise to a shoulder of the main transition peak at lower temperatures. Small angle X-ray diffraction showed an increase in d-spacing suggesting a thicker membrane in the presence of both ubiquinone-10 and ubiquinol-10, below the phase transition and a remarkable broadening of the peaks indicating a loss of the repetitive pattern of the lipid multilamellar vesicles. Infrared spectroscopy showed an increase in wavenumbers of the maximum of the CH 2 stretching vibration at temperatures below the phase transition, in the presence of ubiquinol-10, indicating an increase in the proportion of gauche isomers in the gel phase, whereas this effect was smaller for ubiquinone-10. A very small effect was observed at temperatures above the phase transition. (2)H NMR spectroscopy of perdeuterated DMPC showed only modest changes in the spectra of the phospholipids occasioned by the presence of coenzyme Q 10. These small changes were reflected, in the presence of ubiquinol-10, by a decrease in resolution indicating that the interaction between coenzyme Q and phospholipids changed the motion of the lipids. The change was also visible in the first spectral moment (M1), which is related with membrane order, which was slightly decreased at temperatures below the phase transition especially with ubiquinol-10. A slight decrease in M 1 values was also observed above the phase transition but only for ubiquinol-10. These results can be interpreted to indicate that most ubiquinone-10 molecules are localized in the center of the bilayer, but a considerable proportion of ubiquinol-10 molecules may span the bilayer interacting more extensively with the phospholipid acyl chains.
已通过差示扫描量热法、X射线衍射、红外光谱和（2）H核磁共振研究了氧化型（泛醌-10）和还原型（泛醇-10）辅酶Q 10与二肉豆蔻酰磷脂酰胆碱之间的相互作用。微量热法实验表明，泛醇-10对磷脂相变的干扰比泛醌-10大得多，两种形式都会在较低温度下产生主转变峰的肩峰。小角X射线衍射显示d间距增加，表明在泛醌-10和泛醇-10存在下，低于相变温度时膜更厚，并且峰显著变宽，表明脂质多层囊泡的重复模式丧失。红外光谱显示，在低于相变温度时，在泛醇-10存在下，CH 2伸缩振动最大值的波数增加，表明凝胶相中gauche异构体的比例增加，而泛醌-10的这种效应较小。在高于相变温度时观察到非常小的效应。全氘代DMPC的（2）H核磁共振光谱显示，辅酶Q 10的存在仅使磷脂光谱发生适度变化。在泛醇-10存在下，这些小变化反映为分辨率降低，表明辅酶Q与磷脂之间的相互作用改变了脂质的运动。这种变化在与膜有序性相关的第一光谱矩（M1）中也可见，在低于相变温度时，特别是在泛醇-10存在下，M1略有下降。在高于相变温度时也观察到M 1值略有下降，但仅针对泛醇-10。这些结果可以解释为表明大多数泛醌-10分子位于双层的中心，但相当一部分泛醇-10分子可能跨越双层，与磷脂酰基链更广泛地相互作用。
