Versatile Trityl Spin Labels for Nanometer Distance Measurements on Biomolecules In Vitro and within Cells

作者：Jean Jacques Jassoy, Andreas Berndhäuser, Fraser Duthie, Sebastian P. Kühn, Gregor Hagelueken, Olav Schiemann · 发表于：Angewandte Chemie International Edition · 年份：2016 · DOI：10.1002/anie.201609085 · 被引用次数：135 · 研究领域：Electron Spin Resonance Studies、Lanthanide and Transition Metal Complexes、Magnetism in coordination complexes

Structure determination of biomacromolecules under in-cell conditions is a relevant yet challenging task. Electron paramagnetic resonance (EPR) distance measurements in combination with site-directed spin labeling (SDSL) are a valuable tool in this endeavor but the usually used nitroxide spin labels are not well-suited for in-cell measurements. In contrast, triarylmethyl (trityl) radicals are highly persistent, exhibit a long relaxation time and a narrow spectral width. Here, the synthesis of a versatile collection of trityl spin labels and their application in in vitro and in-cell trityl-iron distance measurements on a cytochrome P450 protein are described. The trityl labels show similar labeling efficiencies and better signal-to-noise ratios (SNR) as compared to the popular methanethiosulfonate spin label (MTSSL) and enabled a successful in-cell measurement.