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Title: | 光系統 II 核心複合體能量傳遞動力學的理論研究 A Theoretical Study of Energy Transfer Dynamics in the Photosystem II Core Complex |
Authors: | Shou-Ting Hsieh 謝守庭 |
Advisor: | 鄭原忠 |
Keyword: | 光系統 II 核心複合體,單體間能量傳遞,能量調節器, PSII core complex,inter-monomeric excitation energy transfer,energy regulator, |
Publication Year : | 2018 |
Degree: | 碩士 |
Abstract: | 光合作用是地球上生物生存裡非常重要的過程。它開始於光合收 光複合體(LHC),收集太陽光並將能量傳給反應中心(RCs)。作為 氧氣生成引擎的光系統 II(PSII)核心複合體是關鍵的光合作用複合 體之一。PSII 核心複合體是一個對稱二聚體,它包含四個天線複合體
(CP43 和 CP47)和兩個反應中心(RC)。要了解這種複雜的光合作用 複合體中的能量傳輸需要有效的理論模型,這樣的模型可以忠實地再 現系統中的激發態能量轉移過程。在這項工作中,我們基於先前的分 子動力學(MD)模擬研究結果提出了 PSII 核心複合體中激發態能量轉 移的有效模型並根據 modified Redfield theory 計算激發態之間能量轉移 的速率常數。它描述了 297 K 時 CP47、CP43 以及 RC 的吸收光譜以及 PSII 中 37 個發色團之間的全激發能量轉移動力學。此外,在我們的模 型中,也考慮了兩種主要電荷分離途徑 PD1 途徑和 ChlD1 途徑。我們 發現在 PSII 核心複合物的單體中,從 CP43(CP47)到 CP47(CP43) 的激發態能傳遞過程最有可能通過 RC。此外,我們發現 CP47 有作為 能量調節器的功能,它可以傳遞單體之間的激發態能量,並且當兩個 RC 中有一個在關閉的狀態時,使得 PSII 核心複合物保持高效率的電 荷轉移。最後,我們發現 CLA625 可能是兩種 PSII 核心複合物單體之 間能量傳遞的橋樑。我們的結果提出了 PSII 核心複合物構建成二聚體 結構的可能原因。此外,也為理解 PSII 核心複合體中的光捕獲提供了 新的見解,並且展示基於分子動力學模擬和量子化學計算的第一種原 理方法可以有效地用於闡明複雜光合複合體中光捕獲的動力學。 The Photosystem II (PSII) core complex, the engine for oxygen genera- tion, is an important photosynthetic complex. It is a symmetric dimer that contains four antenna complexes (CP43 and CP47) and two reaction cen- ters (RCs). Understanding energy transport in such complex photosynthetic complexes requires theoretical effective models that can faithfully reproduce excitation energy transfer (EET) dynamics. In this work, we present an effec- tive model for EET in the PSII core complex based on a previous molecular dynamics (MD) simulation study. This model describes absorption spectra of CP47, CP43 and RC at 297 K as well as the full EET dynamics among the 74 chromophores in the PSII. Energy transfer rate constants are modeled based on the modified Redfield theory and two pathways of primary charge separation are treated phenomenologically in our model. We show that in the monomer, EET between two antenna complexes most likely occurs presum- ably through the RC. Also, the CLA625s are a bridge between monomers and cause the CP47s to become an energy regulator, which can transfer the excitation energy between monomers and maintain high efficiency of charge transfer when one of RCs is closed. CP47s as an energy regulator may be the reason for the dimeric structure of PSII core complex. Our model provides new insights towards the understanding of light harvesting in the PSII core complex and shows that a first principle approach based on MD simulations and quantum chemistry calculations can be effectively utilized to elucidate the dynamics of light harvesting in photosynthetic complexes. |
URI: | http://tdr.lib.ntu.edu.tw/handle/123456789/1330 |
DOI: | 10.6342/NTU201802891 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 化學系 |
Files in This Item:
File | Size | Format | |
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ntu-107-1.pdf | 2.21 MB | Adobe PDF | View/Open |
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