在强度合的光系统II启发的染色体-伊米达-复合体中进行质子-合电子转移:逐步氧化和协同减少
Gerald F Manbeck1, Etsuko Fujita1, Javier J Concepcion1
1Chemistry Division, Brookhaven National Laboratory , Upton, New York 11973-5000, United States.
Journal of the American Chemical Society
|August 19, 2016
概括
这项研究研究了光系统II灵感复合体中的质子合电子转移 (PCET). 研究人员发现了强大的电子合,并描述了关键反应机制,为生物能量转化提供了洞察力.
科学领域:
- 生物有机化学
- 摄影化学
- 电子转移反应
背景情况:
- 光系统II (PSII) 使用质子合电子转移 (PCET) 进行水氧化.
- 了解PCET机制对于人工光合作用和能量转化至关重要.
- 模仿PSII的功能需要强大的合成类似物.
研究的目的:
- 为了研究光系统II灵感的复合体中的PCET反应.
- 阐明分子内部电子和质子转移的机制.
- 将合成复合物的行为与自然PSII过程进行比较.
主要方法:
- 使用闪灭序列生成Ru (III) 在[Ru (bpy) 2 (phen-imidazole-Ph (OH) 2 (t) Bu (2)) 2+]复合体中.
- 在酸溶剂中研究PCET反应.
- 分析了反应动力学,动态同位素效应 (KIE) 和电子合参数.
主要成果:
- 通过循序渐进的电子转移-质子转移 (ET-PT) 机制,通过Ru(III) 证明了的分子内氧化.
- 电子转移的特征是具有强大的电子合.
- 观察到一个协同的,非adiabatic重组反应与反向的动态同位素效应.
结论:
- 合成复合体表现出强大的电子合,促进有效的PCET.
- 在重组步骤中观察到的反向KIE为振动合提供了新的见解.
- 这项研究为人工和自然光合作用系统提供了有价值的机械学知识.
更多相关视频
10:21Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
9.1K
10:03Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
18.5K
相关概念视频
Photosystem II
79.8K
The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ultimately to photosystem I (PSI) through the electron transport chain. The pigments responsible for caputirng the light energy in photosystems include chlorophyll a, chlorophyll b, and carotenoids.
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment...
The pigment molecules are arranged across two photosystem domains — the antenna complex and the reaction center. The main aim of the pigment...
79.8K
Photosystem I
71.1K
Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
Both these photosystems work in concert. An excited electron from PSII is relayed to PSI via an electron transport chain in the thylakoid membrane of the chloroplast, which is comprised of the carrier molecule plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As electrons move between PSII and PSI, they lose energy and must be re-energized...
71.1K
Photosystems
8.2K
Photosystems are multiprotein complexes that form the functional units of photosynthesis in plants, algae, and cyanobacteria. They are found embedded in the membrane of tiny sac-like structures called thylakoids placed inside the chloroplast.
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment...
Functioning of Photosystems
Photosystems contain many pigment molecules, such as chlorophylls and carotenoids, arranged in a particular organization across two domains — the antenna complex and the reaction center. The main aim of the pigment...
8.2K
The Photochemical Reaction Center
5.8K
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
5.8K
The Antenna Complex
8.5K
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...
8.5K
The Z-Scheme of Electron Transport in Photosynthesis
14.8K
The light reactions of photosynthesis assume a linear flow of electrons from water to NADP+. During this process, light energy drives the splitting of water molecules to produce oxygen. However, oxidation of water molecules is a thermodynamically unfavorable reaction and requires a strong oxidizing agent. This is accomplished by the first product of light reactions: oxidized P680 (or P680+), the most powerful oxidizing agent known in biology. The oxidized P680 that acquires an electron from the...
14.8K
