Location of the High-Affinity Mn2+ Site in Photosystem II Detected by PELDOR
Location of the High-Affinity Mn2+ Site in Photosystem II Detected by PELDOR
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DOI：
10.1021/acs.jpcb.5b03994
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发表时间：
2015-08-13
影响因子：
3.3
通讯作者：
Mino, Hiroyuki
中科院分区：
文献类型：
--
作者：
Asada, Mizue;Mino, Hiroyuki
利用脉冲电子双共振(PELDOR)技术观察到Y-D(中心点)自由基与Mn2+离子之间1.7 MHz的电子磁偶极子相互作用，在无钙离子和有钙离子存在的情况下，Mn2+离子与一个脱氧光系统(PS II)离子结合。PELDOR信号是根据先前确定的YD中心点自由基上的自旋分布及其在晶体结构中的已知位置计算的，假设特定的Mn2+位置位于析氧络合物中。结果表明，在天然晶体结构中，高亲和力的Mn2+位位于Mn4(A)位。在D1多肽中，Mn2+与轴向配体Asp170和Glu333配位。
The location of the high-affinity Mn2+ site in apo-photosystem (PS) II was investigated by pulsed EPR The electron electron magnetic dipole interaction of 1.7 MHz between the Y-D(center dot) radical and Mn2+ ion was observed using the pulsed electron electron double resonance (PELDOR) technique, and the Mn2+ ion was bound to one apo-PS II in the absence and presence of Ca2+. PELDOR signals were calculated using the previously determined spin distribution on the YD center dot radical and its known position in the crystal structure, assuming that the specific Mn2+ site was located in the oxygen evolving complex. The results show that the high-affinity Mn2+ site is located at the position denoted by Mn4(A) in the native crystal structure. The Mn2+ is coordinated with axial ligands Asp170 and Glu333 in the D1 polypeptide.