Tm-edited DEER echo curves and Python fitting scripts for the paper entitled: "Measurement of an electron–methyl proton probability distance distribution in a protein using Tm-edited double electron-electron resonance EPR spectroscopy"

This deposition contains the full Tm-edited DEER dataset together with Python scripts for global fitting and analysis.Abstract of the paper: Pulsed double electron-electron resonance (DEER) EPR spectroscopy yields electron-electron distance probability distributions, P(ree), between the unpaired electrons of two paramagnetic spin labels. Here we show that phase memory time (Tm)-edited DEER can be used to measure electron-proton distance distributions in a methyl protonated, otherwise fully deuterated, protein spin-labeled with the rigid R1p nitroxide sidechain. This approach takes advantage of distance dependent nuclear spin-driven electron spin decoherence arising from intramolecular dipolar couplings between the unpaired electron on the spin label and neighboring ( 14 Å) from methyl protons. The dependence of the ratio of the intensities of the two peaks in the P(ree) distribution on the total evolution time T of the second echo period of the DEER experiment displays oscillations arising from dipolar electron-methyl proton couplings that can be described and analyzed using the same formalism as that used for determining electron-electron P(ree) distributions from DEER echo curves. Global fitting of a series of DEER echo curves acquired over a range of evolution times T allows one to extract an electron-methyl proton probability distance distribution, P(reH).本数据集包含完整的经Tm（相位记忆时间）编辑的DEER数据集，以及用于全局拟合与分析的Python脚本。相关论文摘要如下：脉冲双电子-电子共振（Double Electron-Electron Resonance, DEER）电子顺磁共振（Electron Paramagnetic Resonance, EPR）光谱可获取两种顺磁性自旋标记物未配对电子间的电子-电子距离概率分布P(r_ee)。本研究证明，经相位记忆时间（phase memory time, Tm）编辑的DEER技术，可用于测量经刚性R1p氮氧自由基侧链（R1p nitroxide sidechain）标记、且仅甲基位点质子化、其余位点全氘代的蛋白质中，电子-质子的距离分布。该方法利用了自旋标记物上未配对电子与邻近（14 Å范围内）甲基质子之间的分子内偶极耦合所引发的、与距离相关的核自旋驱动电子自旋退相干效应。在DEER实验的第二个回波周期中，P(r_ee)分布内两个峰的强度比值随总演化时间T的变化呈现振荡特征，该振荡源于电子-甲基质子偶极耦合，可采用与从DEER回波曲线推导电子-电子P(r_ee)分布完全一致的形式化方法进行描述与分析。对一系列在不同演化时间T下采集的DEER回波曲线进行全局拟合，即可提取得到电子-甲基质子的概率距离分布P(r_eH)。