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

研究了类胡萝卜素在光合作用中的作用，主要是类胡萝卜素在光合作用的捕光中作为有效的天线色素的作用。重点阐述了通过单重态激发态进行能量转移的机制。为此，开发了保持完整能量转移的完整类胡萝卜素-叶绿素蛋白复合体的分离方法。本文主要对色素-蛋白质复合体以及分离的类胡萝卜素分子进行了理论分析和实验研究。首次从褐藻中分离到具有完全能量传递能力的Cartenold-Challen蛋白。2.只有当类胡萝卜素的最大吸收峰红移时，才能观察到能量转移，这归因于周围类胡萝卜素分子的极化率。3.利用时间分辨共振拉曼散射检测到了类胡萝卜素的2AG态，推测2AG态与类胡萝卜素的能量转移有关。Thi…然而，由于色素-蛋白质复合体的寿命很短，因此无法检测到更多的S状态。4.清晰地观察到类胡萝卜素的荧光，阐明了类胡萝卜素与能量传递函数的关系。当类胡萝卜素共轭双键末端存在酮基团时，类胡萝卜素激发态的不对称性被观察到，观察到来自S1态的荧光。它的寿命比类胡萝卜素长，类胡萝卜素在激发态具有对称的结构。这两个因素可以归因于较高的转移效率。在分离的色素-蛋白质复合体中，没有观察到类胡萝卜素的荧光，这可能是因为它在体内的寿命很短。由叶绿素荧光上升估计的转移时间小于2ps。5.对转移过程进行了理论分析。考虑多组态波函数，计算了激励传递矩阵元。对于类胡萝卜素S1态与叶绿素S1态之间的能量传递，主要机制取决于类胡萝卜素的对称性。在对称类胡萝卜素中，四极-偶极相互作用占主导地位，而在不对称类胡萝卜素中，偶极-偶极相互作用可能是主要的传递机制。这是首次明确预测偶极相互作用是光合成颜料体系能量传递的可能机制的理论分析。较少

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