SELF ASSOCIATION OF COPPER(II) TETRAPHENYLPORPHINE IN LIPID BILAYERMEMBRANES

已发现四苯基卟吩铜 (II) (CuTPP) 有利地分配为二肉豆蔻酰磷脂酰胆碱 (DMPC) 囊泡。 定向 DMPC 膜的 EPR 谱 计算机模拟表明 CuTPP 是优先取向的 分子平面垂直于双层表面 低（小于或等于 1/100）CuTPP/DMPC 摩尔比。 然而， 对于高（约 1/25）CuTPP/DMPC 摩尔比，平面 分子变得平行于膜表面。 测量值 CuTPP 与硬脂酸的硝基氧部分之间的碰撞率 使用酸自旋标记位于膜的不同深度 饱和恢复 EPR 光谱得出的结论是 CuTPP取向的变化是自缔合的结果 （结晶）CuTPP 分子靠近脂质双层中心。 自缔合过程取决于 CuTPP/DMPC 摩尔 比例和样品制备后的时间。

Copper (II) tetraphenylporphine (CuTPP) has been found to partition favorably into dimyristoylphosphatidylcholine (DMPC) vesicles. EPR spectra of oriented DMPC membranes together with computer simulations show that the CuTPP is preferentially oriented with the plane of the molecule perpendicular to the bilayer surface at low (less than or equal to 1/100) CuTPP/DMPC molar ratio. However, for a high (ca. 1/25) CuTPP/DMPC molar ratio, the plane of the molecule becomes parallel to the membrane surface. Measurements of the collision rate between CuTPP and the nitroxide moiety of stearic acid spin labels located at different depths in the membrane using saturation recovery EPR spectroscopy led to the conclusion that the change of the CuTPP orientation is the result of self-association (crystallization) of CuTPP molecules near the lipid bilayer center. The self-association process depends both on the CuTPP/DMPC molar ratio and the time after sample preparation.