Keller Katharina, Mertens Valerie, Qi Mian, Nalepa Anna I, Godt Adelheid, Savitsky Anton, Jeschke Gunnar, Yulikov Maxim
Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland.
Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
Phys Chem Chem Phys. 2017 Jul 21;19(27):17856-17876. doi: 10.1039/c7cp01524k. Epub 2017 Jun 29.
Extraction of distance distributions between high-spin paramagnetic centers from relaxation induced dipolar modulation enhancement (RIDME) data is affected by the presence of overtones of dipolar frequencies. As previously proposed, we account for these overtones by using a modified kernel function in Tikhonov regularization analysis. This paper analyzes the performance of such an approach on a series of model compounds with the Gd(iii)-PyMTA complex serving as paramagnetic high-spin label. We describe the calibration of the overtone coefficients for the RIDME kernel, demonstrate the accuracy of distance distributions obtained with this approach, and show that for our series of Gd-rulers RIDME technique provides more accurate distance distributions than Gd(iii)-Gd(iii) double electron-electron resonance (DEER). The analysis of RIDME data including harmonic overtones can be performed using the MATLAB-based program OvertoneAnalysis, which is available as open-source software from the web page of ETH Zurich. This approach opens a perspective for the routine use of the RIDME technique with high-spin labels in structural biology and structural studies of other soft matter.
从弛豫诱导偶极调制增强（RIDME）数据中提取高自旋顺磁中心之间的距离分布会受到偶极频率泛音的影响。如先前提出的，我们通过在蒂洪诺夫正则化分析中使用修正的核函数来考虑这些泛音。本文以Gd（III）-PyMTA配合物作为顺磁高自旋标记，分析了这种方法在一系列模型化合物上的性能。我们描述了RIDME核的泛音系数校准，证明了用这种方法获得的距离分布的准确性，并表明对于我们的一系列Gd标尺，RIDME技术比Gd（III）-Gd（III）双电子-电子共振（DEER）提供更准确的距离分布。包括谐波泛音的RIDME数据的分析可以使用基于MATLAB的程序OvertoneAnalysis来进行，该程序可从苏黎世联邦理工学院网页作为开源软件获取。这种方法为在结构生物学和其他软物质的结构研究中常规使用带有高自旋标记的RIDME技术开辟了前景。
