Pulsed EPR studies of doublet signal and singlet-like signal in oriented Ca2+-depleted PS II membranes: location of the doublet signal center in PS II.
Pulsed EPR studies of doublet signal and singlet-like signal in oriented Ca2+-depleted PS II membranes: location of the doublet signal center in PS II.
复制标题
定向 Ca2 耗尽的 PS II 膜中双峰信号和单峰信号的脉冲 EPR 研究：PS II 中双峰信号中心的位置。
作者：
H. Mino;A. Kawamori;T. Ono
用脉冲EPR技术研究了PS Ⅱ膜在Ca ~（2+）耗尽后产生的双峰信号和类单峰信号。双峰信号的频谱随外加磁场的变化呈现出明显的角度依赖性，说明产生双峰信号的主要原因是磁偶极-偶极相互作用。单线态信号也表现出角度依赖性，这是不太明显的双峰信号。偶极和交换相互作用的参数用于模拟的双重信号表明，该信号来自磁耦合的有机自由基对。双重信号的角度依赖性表明，径向对（r）和类囊体膜的法线的径向矢量是在65度的角度。定向膜中的脉冲ELDOR研究表明，连接双信号中心与Y（D）（*）基和类囊体膜平面的矢量（R）成8度角。此外，R和r矢量在类囊体膜平面上的投影之间的角度被确定为64度。的位置的双重信号物种在PS II进行了讨论。
Doublet signal and singlet-like signal induced in Ca(2+)-depleted PS II were investigated by pulsed EPR in one-dimensionally oriented photosystem (PS) II membranes. The doublet signal showed marked angular dependent change in its spectrum in term of the applied magnetic field, indicating that the magnetic dipole-dipole interaction is mainly responsible for the doublet signal. The singlet-like signal also showed angular dependence, which was less pronounced than that of the doublet signal. The parameters of dipole and exchange interactions used to simulate the doublet signal indicate that the signal arises from a magnetically coupled organic radical pair. Angular dependence of the doublet signal indicates that the radius vector of the radical pair (r) and the normal of the thylakoid membrane is at an angle of 65 degrees. Pulsed ELDOR studies in the oriented membranes indicate that the vector (R) connecting the doublet-signal center with the Y(D)(*) radical and the plane of the thylakoid membrane are at an angle of 8 degrees. Furthermore, the angle between the projections of the R and r vectors on the plane of the thylakoid membrane was determined to be 64 degrees. The location of the doublet-signal species in PS II is discussed.