Gadolinium(III) Spin Labels for High-Sensitivity Distance Measurements in Transmembrane Helices
Gadolinium(III) Spin Labels for High-Sensitivity Distance Measurements in Transmembrane Helices
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DOI：
10.1002/anie.201305574
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发表时间：
2013-11-04
影响因子：
16.6
通讯作者：
Goldfarb, Daniella
中科院分区：
文献类型：
--
作者：
Matalon, Erez;Huber, Thomas;Goldfarb, Daniella
通过脉冲EPR技术测定生物分子上两个自旋标记物之间的距离已成为一种有吸引力的方法来探测冷冻溶液中生物分子的构象和组装。[1-3]在这些技术中，双电子-电子共振（DEER或PELDOR）[4，5]可以访问1.7至8 nm范围内的距离，是非常受欢迎的，[6-8]并且最广泛使用的自旋标记物是氮氧自由基。自然环境中的膜蛋白对于DEER应用特别感兴趣，因为这些对X射线晶体学和NMR光谱学提出了相当大的挑战。在重构膜或模型膜[9-11]中对肽和蛋白质的DEER研究比在溶液中的那些更具挑战性，因为膜中自旋的高局部浓度降低了相记忆时间，因此降低了灵敏度。[12]大多数氮氧自由基标记的生物分子的DEER测量是在X波段频率（9.5 GHz，0.35 T）进行的，最近这种测量在冷冻细胞中得到了证实。[13这种测量的主要困难是细胞中氮氧化合物的还原，这严重限制了这种令人兴奋的发展的范围。
Distance determination, by pulse EPR techniques, between two spin labels attached to biomolecules has become an attractive methodology to probe conformations and assemblies of biomolecules in frozen solutions.[1–3] Among these techniques, double electron-electron resonance (DEER or PELDOR),[4, 5] which can access distances in the range of 1.7 to 8 nm, is highly popular,[6–8] and the most widely used spin labels are nitroxide radicals. Membrane proteins in their natural environment are of particular interest for DEER applications, since those pose a considerable challenge for X-ray crystallography and NMR spectroscopy. DEER studies of peptides and proteins in either reconstituted or model membranes [9–11] are considerably more challenging than those in solution, because the high local concentration of the spins in the membrane decreases the phase memory time and, therefore, sensitivity.[12] Most DEER measurements on nitroxide-labeled biomolecules are carried out at X-band frequencies (9.5 GHz, 0.35 T), and recently such measurements were demonstrated in frozen cells.[13, 14] A major difficulty of such measurements is the reduction of nitroxides in the cell, which severely limits the scope of such exciting developments.