Dynamics of photoelectric conversion in biological system as studied by high time resolution and high frequency EPR

本文采用高时间分辨率和高频率的ESR实验，对来自贫铀蓝藻脂聚球菌（Synechococcus lividus）的光系统I （PSI）进行了研究。通过监测激光闪光后不同延时时间的电子自旋回波信号，测量了自旋动力学。假设存在弱相互作用的自旋相关自由基对，动力学曲线几乎可以用两个时间常数拟合，表明自旋动力学涉及两种自旋自由基对。结果表明，PSI中存在双向电子传递。

In this work, high time resolution and high frequency ESR experiments were performed for Photosystem I (PSI) from the deuterated cyanobacterium Synechococcus lividus. Spin dynamics were measured by monitoring the electron spin echo signals with different delay times after the laser flash (DAF). Assuming a weakly interacting spin-correlated radical pair, the kinetic curve can be almost fit with two time constants, indicating that the spin dynamics involve two kinds of radical pairs in PSI. It was concluded that bidirectional electron transfer occurs in PSI.