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Development of Frequency Swept EPR under the Low Magnetic Field

低磁场下扫频EPR的研制

基本信息

批准号：
10044057
负责人：
YAMAUCHI Seigo
金额：
$ 3.52万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for international Scientific Research
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10044057/
关键词：
High frequency EPR Time-resolved EPR Excited quintet state Excited quartet state Molecular motion Two dimensional EPR Heme protein Resonance Raman spectroscopy 励起多重項溶液中の三重項電子スピン分極分子ダイナミクスイエロータンパク励起三重項 2次元ESR パルスESR ヘムタ

项目摘要

Collaborative studies were made by use of two techniques, electron paramagnetic resonance(EPR) and vibrational (Raman) spectroscopy, giving the following results.For EPR, we collaborated with four laboratories, Prof.Moebius's at Free University of Berlin, Prof.Corvaja's at Padova University in Italy, Prof.Levanon's at Hebrew University of Jerusalem, and Prof.Kothe's at Freiburg University in Germany, where we made the experiments and discussion. For Raman, Dr.Unno visited Prof.Champion's lab. at Northeastern University of Boston and ran experiments for two weeks.1. In a system of metallo(Zn and Mg) porphyrin-nitroxide radical, we observed excited doublet and quartet states for the first time by EPR techniques, which are separated nicely by means of high frequency (95 GHz) EPR.2. EPR signals of the excited triplet states were observed for the first time in solution using metallo-porphyrins and -phthalocyanines up to +90℃. From the spectral simulation, averaging over the Jahn-Teller split states and molecular motions were analyzed , which indicates that this method is very useful for analyses of excited triplet properties in solution.3. Two dimensional (2D) pulsed EPR techniques were developed to determine spin multiplicity of the excited multiplet states and applied to studies in systems of bisradical linked fullerene. On excitation the excited quintet states were observed and definitely assigned for the first time and the electronic structures were analyzed.4. The resonance Raman investigation was made for oxygenated cytochrome P450 and a structural marker band was successfully assigned at the active site. The observation of the Fe-O-O bending mode reveals structural specificity of the enzyme.

我们利用电子顺磁共振(EPR)和振动(拉曼)光谱两种技术进行了合作研究，得到了以下结果。对于EPR，我们与柏林自由大学的Moebius教授、意大利帕多瓦大学的Corvaja教授、耶路撒冷希伯来大学的Levanon教授和德国弗莱堡大学的Kothe教授合作，在那里我们进行了实验和讨论。为了拉曼，Unno博士参观了Champion教授的实验室。在波士顿东北大学，并进行了两周的实验。在金属(锌和镁)卟啉-氮氧化物体系中，我们首次用EPR技术观察到了激发态双重态和四重态，并用高频(95 GHz)电子顺磁共振很好地分离了它们。在+90℃的范围内，首次用金属卟啉和-酞菁在溶液中观察到了激发三重态的电子顺磁共振信号。从光谱模拟出发，分析了Jahn-Teller分裂态的平均化和分子运动，表明该方法对于分析溶液中激发三重态的性质是非常有用的。发展了二维脉冲EPR技术来确定激发多重态的自旋多重数，并将其应用于双自由基富勒烯体系的研究。在激发时，首次观察到并确定了激发的五重态，并对其电子结构进行了分析。对含氧细胞色素P450进行了共振拉曼光谱研究，并在活性中心成功地指定了一条结构标记带。对Fe-O-O弯曲模式的观察揭示了该酶的结构特异性。