Azarkh Mykhailo, Bieber Anna, Qi Mian, Fischer Jörg W A, Yulikov Maxim, Godt Adelheid, Drescher Malte
Department of Chemistry , University of Konstanz , Universitätsstraße 10 , 78457 Konstanz , Germany.
Faculty of Chemistry and Center for Molecular Materials (CM2) , Bielefeld University , Universitätsstraße 25 , 33615 Bielefeld , Germany.
J Phys Chem Lett. 2019 Apr 4;10(7):1477-1481. doi: 10.1021/acs.jpclett.9b00340. Epub 2019 Mar 18.
In-cell distance determination by electron paramagnetic resonance (EPR) spectroscopy reveals essential structural information about biomacromolecules under native conditions. We demonstrate that the pulsed EPR technique RIDME (relaxation induced dipolar modulation enhancement) can be utilized for such distance determination. The performance of in-cell RIDME has been assessed at Q-band using stiff molecular rulers labeled with Gd(III)-PyMTA and microinjected into Xenopus laevis oocytes. The overtone coefficients are determined to be the same for protonated aqueous solutions and inside cells. As compared to in-cell DEER (double electron-electron resonance, also abbreviated as PELDOR), in-cell RIDME features approximately 5 times larger modulation depth and does not show artificial broadening in the distance distributions due to the effect of pseudosecular terms.
通过电子顺磁共振（EPR）光谱法进行细胞内距离测定，可揭示天然条件下生物大分子的重要结构信息。我们证明了脉冲EPR技术RIDME（弛豫诱导偶极调制增强）可用于此类距离测定。已在Q波段使用标记有Gd(III)-PyMTA并显微注射到非洲爪蟾卵母细胞中的刚性分子尺评估了细胞内RIDME的性能。质子化水溶液和细胞内的泛音系数被确定为相同。与细胞内DEER（双电子-电子共振，也简称为PELDOR）相比，细胞内RIDME的调制深度大约大5倍，并且由于赝旋项的影响，在距离分布中不会出现人为展宽。
