PM-SP-LB多层膜中BR分子的有序定向排列

用垂直转移法在石英片上制成的PM—SP—LB多层膜的可见区吸收谱表明吸收峰峰位与成膜液一致,均在574nm左右,比PM水悬浮液的吸收峰位略有红移;稳态线二色性表明,除PM碎片平躺在多层膜平面内外,在提拉时的竖直方向存在BR的取向优势,优势率约为0.51左右;同时还表明,25mN/m条件下制备的PM—SP—LB多层膜中BR分子的视黄醛生色团的跃迁矩与膜平面法向所成的角接近于天然紫膜中的值。

LINEAR DICHROISM STUDIES OF THE ORIENTATION OF BACTERIORHODOPSIN IN LANGMUIR-BLODGETT MULTILAYER FILM

Purple membrane(PM)-soybean phospholipid(SP) interface film were obtained by spreading onto a clear air-water interface a suspension of PM fragments in a SP n-hexane solution. PM-SP-Langmuir Blodgett(LB) multilayer film, deposited on quartz plate by vertical transfer method (vertical dipping), were studied by linear dichroism. The peak of visible absorption of the 60 layers LB film is about 574 nm, agreed with the film-forming soultiong, both peaks were red shifted with respect to the PM aqueous suspension The linear dichroism studies suggested that, bacteriorhodopsin has a preferred orientation with preferential ratio about 0.51 in the vertical dipping direction in addition to PM fragments lie on the multilayer plane. It also suggested that, the direction of orientation of the moment of the retinal chromophore with respect to the normal to the multilayer plane, is closed to the value in natural PM fragments.