作者:Alberto Collauto、Sören Bülow、Dnyaneshwar B. Gophane、Subham Saha、Lukas S. Stelzl、Gerhard Hummer、Snorri T. Sigurdsson、Thomas F. Prisner
DOI:10.1002/anie.202009800
日期:2020.12.14
flexibility of RNA depends sensitively on the microenvironment. Using pulsed electron‐electron double‐resonance (PELDOR)/double electron‐electron resonance (DEER) spectroscopy combined with advanced labeling techniques, we show that the structure of double‐stranded RNA (dsRNA) changes upon internalization into Xenopus lævis oocytes. Compared to dilute solution, the dsRNA A‐helix is more compact in cells. We recapitulate
RNA 的结构和灵活性敏感地取决于微环境。利用脉冲电子-电子双共振(PELDOR)/双电子-电子共振(DEER)光谱结合先进的标记技术,我们发现双链RNA(dsRNA)的结构在内化到非洲爪蟾卵母细胞后发生变化。与稀溶液相比,细胞中的 dsRNA A 螺旋更加紧凑。我们在密集的蛋白质溶液中重现了这种压缩。dsRNA 的原子分辨率分子动力学模拟半定量捕获压实,并确定蛋白质和 dsRNA 之间的非特异性静电相互作用作为这种效应的可能驱动因素。
Reduction Resistant and Rigid Nitroxide Spin-Labels for DNA and RNA
作者:Haraldur Y. Juliusson、Snorri Th. Sigurdsson
DOI:10.1021/acs.joc.9b02988
日期:2020.3.20
paramagnetic resonance (EPR) spectroscopy, coupled with site-directed spinlabeling (SDSL), is a useful method for studying conformational changes of biomolecules in cells. To employ in-cell EPR using nitroxide-based spinlabels, the structure of the nitroxides must confer reduction resistance to withstand the reductive environment within cells. Here, we report the synthesis of two new spinlabels, EÇ and EÇm
Sterically shielded spin labels for in-cell EPR spectroscopy: Analysis of stability in reducing environment
作者:A. P. Jagtap、I. Krstic、N. C. Kunjir、R. Hänsel、T. F. Prisner、S. Th. Sigurdsson
DOI:10.3109/10715762.2014.979409
日期:2015.1.2
Electron paramagnetic resonance (EPR) spectroscopy is a powerful and widely used technique for studying structure and dynamics of biomolecules under bio-orthogonal conditions. In-cell EPR is an emerging area in this field; however, it is hampered by the reducing environment present in cells, which reduces most nitroxide spin labels to their corresponding diamagnetic N-hydroxyl derivatives. To determine which radicals are best suited for in-cell EPR studies, we systematically studied the effects of substitution on radical stability using five different classes of radicals, specifically piperidine-, imidazolidine-, pyrrolidine-, and isoindoline-based nitroxides as well as the Finland trityl radical. Thermodynamic parameters of nitroxide reduction were determined by cyclic voltammetry; the rate of reduction in the presence of ascorbate, cellular extracts, and after injection into oocytes was measured by continuous-wave EPR spectroscopy. Our study revealed that tetraethyl-substituted nitroxides are good candidates for in-cell EPR studies, in particular pyrrolidine derivatives, which are slightly more stable than the trityl radical.