Double electron electron resonance (DEER) spectroscopy is an important technique to measure distance distributions P(r) for studying protein structures and protein–protein interactions. DEER data analysis can at times become challenging due to the lack of a detailed analytical signal expression or numerical methods with rapid computation time. We have derived an analytical expression κ_FULL, which includes both the pseudo-secular dipolar coupling (PSDC) and the finite pulse effects, especially important for shorter distances. Analyses of experiments by κ_FULL yield accurate and consistent P(r) values for three DEER nitroxide-rulers with distances (r_AVG) in the range of 15 to 32 Å, while the current standard analysis produces erroneous results for r_AVG < 20 Å. Computation times for deriving P(r) vary between 1 min and 4 min, which is usually much shorter than previous methods that include pseudo-secular and other effects. The expression can be applied to all types of DEER spin probes with little or no modifications.

中文翻译：

---

快速分析 DEER 信号，包括短距离


双电子电子共振 （DEER） 光谱是测量距离分布 P（r） 的重要技术，用于研究蛋白质结构和蛋白质-蛋白质相互作用。由于缺乏详细的分析信号表达式或计算时间短的数值方法，DEER 数据分析有时会变得具有挑战性。我们推导出了一个解析表达式 κ_FULL，它包括伪长期偶极耦合 （PSDC） 和有限脉冲效应，这对于较短的距离尤其重要。通过 κ_FULL 对三把距离 （r_AVG） 在 15 至 32 Å 范围内的 DEER 氮氧化物标尺进行实验分析，得出准确且一致的 P（r） 值，而目前的标准分析对 r_AVG < 20 Å 产生错误的结果。推导 P（r） 的计算时间在 1 分钟到 4 分钟之间变化，这通常比以前包含伪世俗和其他效应的方法短得多。该表达可应用于所有类型的 DEER 自旋探针，只需少量或无需修饰。