Peloquin J M, Britt R D
Department of Chemistry, University of California, 1 Shields Avenue, Davis, CA 95616, USA.
Biochim Biophys Acta. 2001 Jan 5;1503(1-2):96-111. doi: 10.1016/s0005-2728(00)00219-x.
Electron paramagnetic resonance (EPR) spectroscopy has often played a crucial role in characterizing the various cofactors and processes of photosynthesis, and photosystem II and its oxygen evolving chemistry is no exception. Until recently, the application of EPR spectroscopy to the characterization of the oxygen evolving complex (OEC) has been limited to the S2-state of the Kok cycle. However, in the past few years, continuous wave-EPR signals have been obtained for both the S0- and S1-state as well as for the S2 (radical)(Z)-state of a number of inhibited systems. Furthermore, the pulsed EPR technique of electron spin echo electron nuclear double resonance spectroscopy has been used to directly probe the 55Mn nuclei of the manganese cluster. In this review, we discuss how the EPR data obtained from each of these states of the OEC Kok cycle are being used to provide insight into the physical and electronic structure of the manganese cluster and its interaction with the key tyrosine, Y(Z).
电子顺磁共振（EPR）光谱在表征光合作用的各种辅因子和过程中常常发挥着关键作用，光系统II及其放氧化学也不例外。直到最近，EPR光谱在表征放氧复合体（OEC）方面的应用还仅限于科克循环的S2态。然而，在过去几年中，已经获得了许多受抑制体系的S0态和S1态以及S2（自由基）（Z）态的连续波EPR信号。此外，电子自旋回波电子核双共振光谱的脉冲EPR技术已被用于直接探测锰簇中的55Mn核。在这篇综述中，我们讨论了从OEC科克循环的这些状态中获得的EPR数据如何用于深入了解锰簇的物理和电子结构及其与关键酪氨酸Y（Z）的相互作用。
