Site-directed spin-labeling electron paramagnetic resonance spectroscopy is a powerful technique for the investigation of protein structure and dynamics. Accurate spin-label modeling methods are essential to make full quantitative use of site-directed spin-labeling electron paramagnetic resonance data for protein modeling and model validation. Using a set of double electron-electron resonance data from seven different site pairs on maltodextrin/maltose-binding protein under two different conditions using five different spin labels, we compare the ability of two widely used spin-label modeling methods, based on accessible volume sampling and rotamer libraries, to predict experimental distance distributions. We present a spin-label modeling approach inspired by canonical side-chain modeling methods and compare modeling accuracy with the established methods.

定点自旋标记电子顺磁共振波谱是研究蛋白质结构和动力学的强大技术。准确的自旋标记建模方法对于充分定量利用定点自旋标记电子顺磁共振数据进行蛋白质建模和模型验证至关重要。使用来自麦芽糖糊精/麦芽糖结合蛋白上七个不同位点对的一组双电子-电子共振数据，在两种不同条件下使用五种不同的自旋标签，我们比较了两种广泛使用的自旋标签建模方法的能力，基于可访问的体积采样和旋转异构体库，以预测实验距离分布。我们提出了一种受规范侧链建模方法启发的自旋标签建模方法，并将建模精度与已建立的方法进行了比较。