Electron-Nuclear Spin Dynamics in a Bacterial Photosynthetic Reaction Center
Electron-Nuclear Spin Dynamics in a Bacterial Photosynthetic Reaction Center
复制标题
DOI：
10.1021/jp900286q
复制
发表时间：
2009-06-11
影响因子：
3.7
通讯作者：
Jeschke, Gunnar
中科院分区：
文献类型：
--
作者：
Daviso, Eugenio;Alia, A.;Jeschke, Gunnar
已知固态光CIDNP效应发生在天然光合反应中心（RC）中，其中与在黑暗中进行的实验相比，可以通过魔角旋转（MAS）NMR观察到固态光CIDNP效应为在照明下信号强度的强烈改变。这种效应的起源一直存在争议。在本文中，我们报告的时间分辨photo-CIDNP MAS NMR数据的反应中心的醌贫化球形红细菌。它表明，核极化的主要捐助者和细菌脱镁叶绿素受体的建立取决于捐助者和类胡萝卜素的分子三重态的存在和寿命。数据分析证明，多达三个电子-核自旋耦合机制和两个瞬态效应在反应中心的自旋化学机制中同时起作用。
The solid-state photo-CIDNP effect is known to occur in natural photosynthetic reaction centers (RCs) where it can be observed by magic-angle spinning (MAS) NMR as strong modification of signal intensities under illumination compared to experiments performed in the dark. The origin of the effect has been debated. In this paper, we report time-resolved photo-CIDNP MAS NMR data of reaction centers of quinone depleted Rhodobacter sphaeroides. It is demonstrated that the build-up of nuclear polarization on the primary donor and the bacteriopheophytin acceptor depends on the presence and lifetimes of the molecular triplet states of the donor and carotenoid. Analysis of the data proves that up to three electron-nuclear spin-coupling mechanisms and two transient effects are working concomitantly in the spin-chemical machinery of the reaction center.