Electron spin density distribution in the special pair triplet of Rhodobacter sphaeroides R26 revealed by magnetic field dependence of the solid-state photo-CIDNP effect.
Electron spin density distribution in the special pair triplet of Rhodobacter sphaeroides R26 revealed by magnetic field dependence of the solid-state photo-CIDNP effect.
复制标题
固态光 CIDNP 效应的磁场依赖性揭示了球形红细菌 R26 特殊对三重态中的电子自旋密度分布。
DOI：
10.1021/ja2117377
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发表时间：
2012
影响因子：
15
通讯作者：
J. Matysik
中科院分区：
文献类型：
--
作者：
Smitha Surendran Thamarath;B. Bode;S. Prakash;K. B. Sai Sankar Gupta;A. Alia;G. Jeschke;J. Matysik
光化学诱导动态核极化（photochemical induced dynamic nuclear polarization，简称cidnp）可以在冷冻和醌阻断的光合反应中心（RCs）中观察到，这是光照下幻角旋转（MAS）核磁共振信号强度的改变。对球形红杆菌（Rhodobacter sphaeroides）无类胡萝卜素突变株R26进行了实验和理论分析，证明了三自旋混合和微分衰变机制对核自旋极化的贡献可以与单线态和三重态分支的微分弛豫（DR）部分维持的自由基对机制产生的极化区分开来。在1.4 T的磁场下，后一种贡献导致信号显著增强约80,000，并且优于其他两种机制。DR机制编码了供体三重态中自旋密度分布的信息。光- cidnp光谱中的相对峰强度为计算不同模型化学和构象的三重态自旋密度提供了关键测试。未配对的电子几乎均匀地分布在特殊的细菌叶绿素对的两个部分上，仅在L分支上有轻微的过量。
Photo-CIDNP (photochemically induced dynamic nuclear polarization) can be observed in frozen and quinone-blocked photosynthetic reaction centers (RCs) as modification of magic-angle spinning (MAS) NMR signal intensity under illumination. Studying the carotenoidless mutant strain R26 of Rhodobacter sphaeroides, we demonstrate by experiment and theory that contributions to the nuclear spin polarization from the three-spin mixing and differential decay mechanism can be separated from polarization generated by the radical pair mechanism, which is partially maintained due to differential relaxation (DR) in the singlet and triplet branch. At a magnetic field of 1.4 T, the latter contribution leads to dramatic signal enhancement of about 80,000 and dominates over the two other mechanisms. The DR mechanism encodes information on the spin density distribution in the donor triplet state. Relative peak intensities in the photo-CIDNP spectra provide a critical test for triplet spin densities computed for different model chemistries and conformations. The unpaired electrons are distributed almost evenly over the two moieties of the special pair of bacteriochlorophylls, with only slight excess in the L branch.
通过 (13)C 魔角旋转 NMR 光谱观察趋光素 LOV1-C57S 中的固态光 CIDNP 效应
影响因子：
15
作者：
S. S. Thamarath;J. Heberle;P. Hore;T. Kottke;J. Matysik
通讯作者：
J. Matysik
影响因子：
56.9
作者：
Stowell, MHB;McPhillips, TM;Feher, G
通讯作者：
Feher, G
34 GHz 低温脉冲 EPR 研究球形红杆菌天然和突变细菌反应中心的初级电子供体 P865 和类胡萝卜素的三重态。
影响因子：
2.9
作者：
Marchanka,Aliaksandr;Paddock,Mark;Lubitz,Wolfgang;vanGastel,Maurice
通讯作者：
vanGastel,Maurice