The determination of pair distance distributions by pulsed ESR using Tikhonov regularization
The determination of pair distance distributions by pulsed ESR using Tikhonov regularization
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DOI：
10.1016/j.jmr.2004.10.012
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发表时间：
2005-02-01
影响因子：
2.2
通讯作者：
Freed, JH
中科院分区：
文献类型：
--
作者：
Chiang, YW;Borbat, PP;Freed, JH
脉冲ESR技术与定点自旋标记的帮助下，已被证明是有用的，在提供有关蛋白质的独特结构信息。本文报道用吉洪诺夫正则化方法直接从脉冲ESR信号的偶极时间演化中确定电子自旋对的距离分布。与数值反演这个不适定的数学问题的困难清楚地说明。然后描述了正则化参数由L曲线准则确定的Tikhonov正则化，并对其进行了测试，以确认其准确性和可靠性。该方法适用于最近的实验结果，双标记的蛋白质，已经研究了使用两个脉冲ESR技术，双量子相干（DQC）ESR和双电子-电子共振（DEER）。提取的距离分布能够提供有价值的信息，在各种部分折叠状态的蛋白质的构象约束。这项研究提供了一个数学上可靠的方法提取对分布的脉冲ESR实验数据，并扩展了脉冲ESR的使用，提供更大的结构生物学价值的结果。(C)2004年爱思唯尔公司All rights reserved.
Pulsed ESR techniques with the aid of site-directed spin labeling have proven useful in providing unique structural information about proteins. The determination of distance distributions in electron spin pairs directly from the dipolar time evolution of the pulsed ESR signals by means of the Tikhonov reularization method is reported. The difficulties connected with numerically inverting this ill-posed mathematical problem are clearly illustrated. The Tikhonov regularization with the regularization parameter determined by the L-curve criterion is then described and tested to confirm its accuracy and reliability. The method is applied to recent experimental results on doubly labeled proteins that have been studied using two pulsed ESR techniques, double quantum coherence (DQC) ESR and double electron-electron resonance (DEER). The extracted distance distributions are able to provide valuable information about the conformational constraints in various partially folded states of proteins. This study supplies a mathematically reliable method for extracting pair distributions from pulsed ESR experimental data and has extended the use of pulsed ESR to provide results of greater value for structural biology. (C) 2004 Elsevier Inc. All rights reserved.