在光合作用水氧化过程中通过D1-E65/D2-E312门进行质子转移的机制
1Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan.
The journal of physical chemistry. B
|February 16, 2024
概括
在光系II中进行质子转移.
科学领域:
- 生物化学 生化学
- 光合作用研究研究光合作用.
- 分子生物物理学的分子生物物理学.
背景情况:
- 光系II的Cl-1通道中的D1-E65/D2-E312二涉及到水氧化质子转移.
- 在这个通道中,质子转移的确切机制尚不清楚.
研究的目的:
- 阐明光系统II的Cl-1通道内的质子转移机制.
- 研究D1-E65/D2-E312二在促进水氧化过程中的质子运动中的作用.
主要方法:
- 使用量子力学/分子力学 (QM/MM) 的计算.
- 分析了E65/E312二的分子振动和化效应.
主要成果:
- 一个涉及初始释放和缓慢反质子化的阶段性质子转移机制被驳斥了.
- 建议通过E65/E312二的形状门机制进行质子转移.
- 双在封闭形式 (捕获质子) 和开放形式 (促进转移) 之间进行过渡.
结论:
- D1-E65/D2-E312双作为一个门,控制Cl-1通道中的质子转移.
- 开放形式的D1-E65质子使格罗托斯型的质子转移到水网中.
- 这种形状关门机制对于光系统II中水的有效氧化至关重要.
相关概念视频
The Z-Scheme of Electron Transport in Photosynthesis
10.1K
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...
10.1K
Photosystem II
70.4K
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...
70.4K
Photosystem I
62.2K
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...
62.2K
Photosystems
4.8K
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...
4.8K
The Photochemical Reaction Center
4.1K
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...
4.1K
Electron Transport Chain: Complex III and IV
7.5K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
7.5K


