A New Gd3+ Spin Label for Gd3+-Gd3+ Distance Measurements in Proteins Produces Narrow Distance Distributions
A New Gd3+ Spin Label for Gd3+-Gd3+ Distance Measurements in Proteins Produces Narrow Distance Distributions
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DOI：
10.1021/acs.jpclett.5b02451
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发表时间：
2015-12-17
影响因子：
5.7
通讯作者：
Goldfarb, Daniella
中科院分区：
文献类型：
--
作者：
Abdelkader, Elwy H.;Lee, Michael D.;Goldfarb, Daniella
Gd 3+标签已被证明是有用的，通过双电子电子共振（DEER）技术在Q-和W-波段的频率在生物分子中进行距离测量。我们介绍了一种新的基于cyclen的Gd 3+标签，表现出相对较窄的电子顺磁共振（EPR）谱，提供高灵敏度，并产生非常窄的Gd 3 +-Gd 3+的距离分布在双标记的蛋白质由于一个非常短的系绳。对于蛋白质ERp 29和T4溶菌酶的标记突变体测量的距离分布的最大值和宽度，其特征在于约100 nm的Gd 3 +-Gd 3+距离。6和4 nm，分别是很好地再现了模拟的距离分布的基础上可用的晶体结构和空间允许的旋转异构体的标签。的Gd 3+离子的位置的精度是可比的MTSL标记的蛋白质中的氮氧自由基，因此，新的标签代表了一个有吸引力的工具，用于执行精确的距离测量和潜在的探测蛋白质构象平衡。
Gd3+ tags have been shown to be useful for performing distance measurements in biomolecules via the double electron electron resonance (DEER) technique at Q- and W-band frequencies. We introduce a new cyclen-based Gd3+ tag that exhibits a relatively narrow electron paramagnetic resonance (EPR) spectrum, affording high sensitivity, and which yields exceptionally narrow Gd3+-Gd3+ distance distributions in doubly tagged proteins owing to a very short tether. Both the maxima and widths of distance distributions measured for tagged mutants of the proteins ERp29 and T4 lysozyme, featuring Gd3+-Gd3+ distances of ca. 6 and 4 nm, respectively, were well reproduced by simulated distance distributions based on available crystal structures and sterically allowed rotamers of the tag. The precision of the position of the Gd3+ ion is comparable to that of the nitroxide radical in an MTSL-tagged protein and thus the new tag represents an attractive tool for performing accurate distance measurements and potentially probing protein conformational equilibria.