AnisoDipFit: Simulation and Fitting of Pulsed EPR Dipolar Spectroscopy Data for Anisotropic Spin Centers
AnisoDipFit: Simulation and Fitting of Pulsed EPR Dipolar Spectroscopy Data for Anisotropic Spin Centers
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DOI：
10.1007/s00723-020-01214-0
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发表时间：
2020-07-28
影响因子：
1
通讯作者：
Abdullin, Dinar
中科院分区：
文献类型：
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作者：
Abdullin, Dinar
脉冲电子顺磁共振偶极光谱(PDS)可以测量电子自旋中心之间的距离，在有利的情况下，还可以测量它们的相对取向。这些数据经常被用于结构生物学，用于研究生物分子结构，跟踪它们的构象变化，并定位其中的顺磁中心。为了从主要的时间域PDS信号中提取自旋间距离和自旋中心的相对取向，需要专门的数据分析。到目前为止，进行这种分析的软件仅适用于各向同性S=1/2自旋中心，如氮氧化物和三叔丁基自由基，以及高自旋Gd(3+)和Mn(2+)离子。本文介绍了一个新的数据分析程序，称为Aniso DipFit，适用于由一个各向同性和一个各向异性S=1/2自旋中心组成的自旋系统。该程序在自旋体系Cu2+/有机自由基、低自旋Fe3+/有机自由基和高自旋Fe3+/有机自由基的PDS数据上进行了成功的测试。对于所有测试的自旋系统，AnisDipFit允许以亚埃精度确定自旋间距离分布。此外，对于后两个自旋系统，确定了自旋间矢量相对于金属中心g轴的空间取向。因此，这项研究扩大了PDS数据分析程序的武器库，并促进了基于PDS的对高度相关类别的MetolloProtein的距离和角度的测量。
Pulsed electron paramagnetic resonance dipolar spectroscopy (PDS) allows to measure the distances between electron spin centers and, in favorable cases, their relative orientation. This data is frequently used in structural biology for studying biomolecular structures, following their conformational changes and localizing paramagnetic centers within them. In order to extract the inter-spin distances and the relative orientation of spin centers from the primary, time-domain PDS signals, a specialized data analysis is required. So far, the software to do such analysis was available only for isotropicS = 1/2 spin centers, such as nitroxide and trityl radicals, as well as for high-spin Gd(3+)and Mn(2+)ions. Here, a new data analysis program, called AnisoDipFit, was introduced for spin systems consisting of one isotropic and one anisotropicS = 1/2 spin centers. The program was successfully tested on the PDS data corresponding to the spin systems Cu2+/organic radical, low-spin Fe3+/organic radical, and high-spin Fe3+/organic radical. For all tested spin systems, AnisoDipFit allowed determining the inter-spin distance distribution with a sub-angstrom precision. In addition, the spatial orientation of the inter-spin vector with respect to theg-frame of the metal center was determined for the last two spin systems. Thus, this study expands the arsenal of the PDS data analysis programs and facilitates the PDS-based distance and angle measurements on the highly relevant class of metolloproteins.