Finzi L, Bustamante C, Garab G, Juang C B
Department of Chemistry, University of New Mexico, Albuquerque 87131.
Proc Natl Acad Sci U S A. 1989 Nov;86(22):8748-52. doi: 10.1073/pnas.86.22.8748.
Long-range chiral organization of the pigment-protein complexes in mature granal chloroplasts has been established by differential polarization imaging and local circular dichroism spectra. Linear and circular dichroism images of oriented chloroplasts were obtained in a confocal differential polarization microscope. The circular dichroism images display signals of opposite signs emerging from discrete regions with local dichroic values much larger than anticipated, indicating domains in the thylakoid membranes having long-range chiral organization. These domains are associated with positive and negative circular dichroism bands obtained at specific locations on the chloroplasts. Surprisingly, the local circular dichroism spectra do not display the excitonic shape of spectra obtained for macroscopic suspensions, but the latter can be produced by superposition of two local spectra of opposite sign. These data are evidence for the existence of long-range chiral order of the pigment-protein complexes in thylakoid membranes. The possible role of the long-range chiral domains in the efficiency of energy delocalization through the thylakoid membranes is discussed.
通过差分偏振成像和局部圆二色光谱，已确定成熟基粒叶绿体中色素 - 蛋白质复合物的长程手性组织。在共焦差分偏振显微镜中获得了取向叶绿体的线性和圆二色图像。圆二色图像显示出从离散区域出现的具有相反符号的信号，其局部二色性值远大于预期，表明类囊体膜中存在具有长程手性组织的结构域。这些结构域与在叶绿体特定位置获得的正负圆二色带相关。令人惊讶的是，局部圆二色光谱并未显示出宏观悬浮液所获得光谱的激子形状，但后者可由两个相反符号的局部光谱叠加产生。这些数据证明了类囊体膜中色素 - 蛋白质复合物存在长程手性序。讨论了长程手性结构域在通过类囊体膜进行能量离域效率方面的可能作用。
