Inter-spin distance determination using L-band (1-2 GHz) non-adiabatic rapid sweep electron paramagnetic resonance (NARS EPR).
Inter-spin distance determination using L-band (1-2 GHz) non-adiabatic rapid sweep electron paramagnetic resonance (NARS EPR).
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DOI：
10.1016/j.jmr.2012.05.006
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发表时间：
2012-08
影响因子：
2.2
通讯作者：
Hyde, James S.
中科院分区：
文献类型：
--
作者：
Kittell, Aaron W.;Hustedt, Eric J.;Hyde, James S.
定点自旋标记电子顺磁共振（SDSL EPR）提供了深入了解局部结构和运动的自旋探针战略性地连接到一个分子。当第二个自旋被引入到系统中时，可以通过连续波（CW）或脉冲电子双共振（ELDOR）技术测量自旋间距离来获得大分子信息。如果考虑这两种方法，则可以通过实验确定8至80 μ m的自旋间距离。然而，在常规X波段（9.5GHz）CW技术的上限和四脉冲双电子-电子共振（DEER）实验的下限存在一个区域，其中两种方法都不是特别可靠。这里提出的工作利用L波段（1.9 GHz）与非绝热快速扫描（NARS）EPR相结合，以解决这个机会，通过增加CW技术的上限。由于L波段的线宽比X波段的线宽窄三到七倍，因此可以观察到相对于X波段不均匀线宽较小的偶极展宽，但是由于玻尔兹曼因子的频率依赖性导致的信号损失使得L波段特别具有挑战性。NARS已被证明可以将灵敏度提高五倍，并克服了这种损失，使L波段距离确定更加可行。两个不同的系统，并已在生理相关的温度下实验确定的距离为18 - 30毫米。测量结果与螺旋模型和DEER确定的值非常一致。
Site-directed spin-labeling electron paramagnetic resonance (SDSL EPR) provides insight into the local structure and motion of a spin probe strategically attached to a molecule. When a second spin is introduced to the system, macromolecular information can be obtained through measurement of inter-spin distances either by continuous wave (CW) or pulsed electron double resonance (ELDOR) techniques. If both methodologies are considered, inter-spin distances of 8 to 80 Å can be experimentally determined. However, there exists a region at the upper limit of the conventional X-band (9.5 GHz) CW technique and the lower limit of the four-pulse double electron-electron resonance (DEER) experiment where neither method is particularly reliable. The work presented here utilizes L-band (1.9 GHz) in combination with non-adiabatic rapid sweep (NARS) EPR to address this opportunity by increasing the upper limit of the CW technique. Because L-band linewidths are three to seven times narrower than those at X-band, dipolar broadenings that are small relative to the X-band inhomogeneous linewidth become observable, but the signal loss due to the frequency dependence of the Boltzmann factor, has made L-band especially challenging. NARS has been shown to increase sensitivity by a factor of five, and overcomes much of this loss, making L-band distance determination more feasible. Two different systems are presented and distances of 18–30 Å have been experimentally determined at physiologically relevant temperatures. Measurements are in excellent agreement with a helical model and values determined by DEER.
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影响因子：
2.2
作者：
Kittell, Aaron W.;Camenisch, Theodore G.;Ratke, Joseph J.;Sidabras, Jason W.;Hyde, James S.
通讯作者：
Hyde, James S.
影响因子：
2.2
作者：
Banham, J. E.;Baker, C. M.;Timmel, C. R.
通讯作者：
Timmel, C. R.
影响因子：
15
作者：
Borbat, PP;Mchaourab, HS;Freed, JH
通讯作者：
Freed, JH
影响因子：
8
作者：
Fleissner, Mark R.;Cascio, Duilio;Hubbell, Wayne L.
通讯作者：
Hubbell, Wayne L.
影响因子：
2.8
作者：
Saxena, S;Freed, JH
通讯作者：
Freed, JH