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Elucidation of Structure and Function of Photosynthetic Antenna by Model Study

通过模型研究阐明光合天线的结构和功能

基本信息

批准号：
09480144
负责人：
TAMIAKI Hitoshi
金额：
$ 7.1万
依托单位：
Ritsumeikan University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Synthesis of Novel Chlorophyllous PigmentsNovel 3ィイD11ィエD1-hydroxy-13ィイD11ィエD1-oxo-chlorins possessing various substituents at 3ィイD11ィエD1-,7-,8-,13ィイD12ィエD1-,17ィイD14ィエD1-and 20-positions and their metal complexes were prepared by modification of naturally occurring chlorophylls.2. Preparation of Artificial ChlorosomesSynthetic metal-chlorins self-aggregated to give any oligomers in non-polar organic solvents. aqueous organic solution, aqueous solutions of detergents, solid thin films and solid powders. Supramolecular structures of the resulting oligomers were investigated by several spectroscopic techniques, indicating that a linear orientation among the hydroxy, keto groups and central metal along the Qy-axis in the molecule is requisite for formation of highly ordered supramolecules and also that magnesium, zinc and cadmium as the central metal were effective for the self-aggregation.All the self-aggregates were built-up mainly by 13-C=・・・H(3-CHR)O・・・M and π-πinteraction of the chlorin chromophores, which are good structural models for natural chlorosomes, extramembranous antennae of photosynthetic green bacteria. Peripheral substituents affected slightly the supramolecular structures of the oligomers, but did not change the framework.In an aqueous solution of a detergent, synthetic pigments self-aggregated at the hydrophobic sphere in the micelle. When a chromophore of a bacteriochlorin moiety was added to the aqueous solution, photoexcited energy of the oligomers was transferred to the added bacteriochlorin, indicating the in vitro self-aggregates are good functional model for natural chlorosomes.Comparison of Natural Chlorosomes with Artificial ChlorosomesNatural chlorophyllous pigments are consisted of several the homologues. It is not unclear how the homologues self-aggregate in the natural systems. In vitro self-aggregation of synthetic pigments gave any information for the mechanism of in vivo self-aggregation.

新型叶绿素颜料的合成新型3ィイD11ィエD1-羟基-13ィイD11ィエD1-氧代-二氢卟酚在以下位置具有各种取代基3ィイD11ィエD1-,7-,8-,13ィイD12ィエD1-,17ィイD14ィエD1-和20位及其金属配合物是通过天然存在的修饰制备的叶绿素.2。人工叶绿体的制备合成金属二氢卟酚在非极性有机溶剂中自聚集以产生任何低聚物。有机水溶液、洗涤剂水溶液、固体薄膜、固体粉末。通过多种光谱技术研究了所得低聚物的超分子结构，表明分子中羟基、酮基和中心金属之间沿Qy轴的线性取向是形成高度有序的超分子的必要条件，并且镁、锌和镉作为中心金属对于自聚集是有效的。自聚集体主要由二氢卟酚发色团的 13-C=···H(3-CHR)O···M 和 π-π 相互作用形成，是天然叶绿体、光合绿色细菌膜外触角的良好结构模型。外围取代基对低聚物的超分子结构略有影响，但不改变骨架。在洗涤剂的水溶液中，合成颜料在胶束的疏水球体处自聚集。当将菌绿素部分的发色团添加到水溶液中时，低聚物的光激发能转移到添加的菌绿素上，表明体外自聚集体是天然叶绿体的良好功能模型。天然叶绿体与人工叶绿体的比较天然叶绿素色素由几种同系物组成。目前尚不清楚同系物如何在自然系统中自我聚集。合成颜料的体外自聚集为体内自聚集机制提供了任何信息。