Function of Carotenoids in Photosynthetic System and Molecular Dynamics as a Fundamenta.

类胡萝卜素在光合系统中的功能和分子动力学基础。

基本信息

批准号：
02305014
负责人：
MIMURO Mamoru
金额：
$ 6.53万
依托单位：
Okazaki National Research Institution, National Institute for Basic Biology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02305014/
关键词：
Carotenoid Photosynthesis Energy transfer Time-resolved spectroscopy Molecular dynamics Pigment-protein complex

项目摘要

Function of carotenoids in photosynthesis was investigated, mainly on the function as efficient antenna pigments in light harvesting for photosynthesis. The main point is elucidation of mechanism of energy transfer through singlet excited states. For that purpose, isolation methods for intact carotenoid-chlorophyll protein complexes which retain complete energy transfer was developed. The analysis was mainly carried out theoretically and experimentally on pigment-protein complexes as well as isolated carotenoid molecules.1. Cartenold-chlorophyll protein which holds full capacity of energy transfer was isolated from the brown alga for the first time. 2. Energy transfer was observed only when the absorption maximum of carotenoid is red-shifted and this is attributed to the polarizability of surrounding molecules of carotenoids. 3. The 2Ag state was detected by the timeresolved reseonance Raman scattering, which is postulated to be responsible for the energy transfer from carotenoids. Thi … More s state in the pigment-protein complex, however, could not be detected due to its very short lifetime in the complexes. 4. Fluorescence from isolated carotenoids was clearly observed and relationship to the energy transfer function was elucidated. When a keto group is present at the end of conjugated double bond of carotenoids, which induce asymmetry in carotenoid excited state, fluorescence from the S1 state was observed. Its lifetime is longer than those of carotenoids which have symmetrical structure in their excited state. These two factors can be attributed to a high transfer efficiency. In the isolated pigment-protein complex, fluorescence from carotenoid was not observed, probably due to its short lifeitme in vivo. The transfer time, estimated from the rise of chlorophyll fluorescence was shorter than 2 ps. 5. Theoretical analysis was carried out on the transfer processes. The excitation transfer matrix element was calculated considering multiconfiguration wave functions. For the energy transfer between S1 state of carotenoid and of chlorophyll, the main mechanism changed depending on the-symmetry of carotenoids. In symmetric carotenoids, the quadrupole-dipole interaction is the predominant, on the other hand, in asymmetric carotenoids, dipoledipole interaction can be a main tranfser mechasnism. This is the first theoretical analysis which clearly predict that the dipole interaction is posssible mechanism in the energy transfer in phototosynthetic pigment systems. Less

胡萝卜素在光合作用中的功能进行了研究，主要基于作为光合作用的光收集中有效的天线色素的功能。要点是通过单线激发态阐明能量转移机理。为此，开发了保留完整能量转移的完整类胡萝卜素 - 氯植物蛋白复合物的分离方法。该分析主要是在理论上进行的，并在色素 - 蛋白质复合物以及分离的类胡萝卜素分子上进行实验。1。首次从棕藻中分离出满足能量转移的全容量的Cartenold-氯植物蛋白。 2。仅当类胡萝卜素的最大吸收被红移时观察到能量转移，这归因于周围类胡萝卜素分子的极化。 3。被定位分辨率拉曼散射检测到2AG状态，该分子散射是负责类胡萝卜素的能量转移的。然而，由于络合物中的寿命很短，因此无法检测到颜料蛋白质复合物中的更多状态。 4。清楚地观察到来自分离的类胡萝卜素的荧光，并阐明了与能量转移功能的关系。当酮基在类胡萝卜素的共轭双键末端存在（诱导类胡萝卜素激发态的不对称性）时，S1状态的荧光比在激发状态具有对称结构的类胡萝卜素的寿命更长。这两个因素可以归因于高传递效率。在分离的色素蛋白质复合物中，未观察到类胡萝卜素的荧光，这可能是由于其在体内寿命短。从叶绿素荧光的上升估计的转移时间短于2 ps。 5。对转移过程进行了理论分析。考虑多构型波函数，计算了兴奋转移矩阵元素。对于类胡萝卜素状态和叶绿素的S1状态之间的能量转移，主要机制根据类胡萝卜素的对称性而改变。在对称类胡萝卜素中，二极 - 偶极相互作用是主要的，在不对称的类胡萝卜素中，二哌丁他的相互作用可能是主要的透射机械性。这是第一个理论分析，可以清楚地预测偶极相互作用是光合成色素系统中能量转移的可能机制。较少的