On the performance of spin diffusion NMR techniques in oriented solids: prospects for resonance assignments and distance measurements from separated local field experiments.
On the performance of spin diffusion NMR techniques in oriented solids: prospects for resonance assignments and distance measurements from separated local field experiments.
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DOI：
10.1021/jp105718r
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发表时间：
2010-11-04
影响因子：
3.3
通讯作者：
Veglia, Gianluigi
中科院分区：
文献类型：
--
作者：
Traaseth, Nathaniel J.;Gopinath, T.;Veglia, Gianluigi
核磁共振自旋扩散实验有可能提供两个共振分配和蛋白质结构测定在定向固态核磁共振的核间距。比较了质子驱动自旋扩散（PDSD）、交叉弛豫驱动自旋扩散（CRDSD）和质子介导质子转移（PMPT）三种常用自旋扩散实验的效率。作为定向蛋白质的模型系统，我们使用N-乙酰基-L-15 N-亮氨酸（NAL）和N-乙酰基-L-15 N-缬氨酰-L-15 N-亮氨酸（NAVL）的单晶分别探测长距离和短距离。我们证明，对于短的15 N/15 N距离，如NAVL（3.3 μ m）中发现的距离，PDSD机制给出了最强烈的交叉峰，而对于较长的距离（> 6.5 μ m），CRDSD和PMPT实验更有效。由于小的15 N/15 N偶极耦合（< 4.5 Hz），PDSD对于跨越大于6.5 Hz的距离（NAL晶体样品）传递磁化是非常低效的。有趣的是，PMPT实验中存在的不匹配的Hartmann-Hahn条件对于较低的1H和15 N自旋锁场强度（分别为32和17 kHz）而不是较高的值（55和50 kHz）给出了更强烈的交叉峰，这表明了更复杂的磁化转移机制。数值模拟结果与实验结果吻合良好，表明PMPT和CRDSD的组合效果。我们的结论是，为了分配SLF光谱和测量短期和长期的距离，结合使用的homopathic相关光谱，如在这项工作中调查的，是必要的。
NMR spin diffusion experiments have the potential to provide both resonance assignment and internuclear distances for protein structure determination in oriented solid-state NMR. In this paper, we compared the efficiencies of three common spin diffusion experiments: proton-driven spin diffusion (PDSD), cross-relaxation driven spin diffusion (CRDSD), and proton-mediated proton transfer (PMPT). As model systems for oriented proteins, we used single crystals of N-acetyl-L-15N-leucine (NAL) and N-acetyl-L-15N-valyl-L-15N-leucine (NAVL) to probe long- and short distances, respectively. We demonstrate that for short 15N/15N distances such as those found in NAVL (3.3 Å), the PDSD mechanism gives the most intense cross-peaks, while for longer distances (> 6.5 Å), the CRDSD and PMPT experiments are more efficient. The PDSD was highly inefficient for transferring magnetization across distances greater than 6.5 Å (NAL crystal sample), due to small 15N/15N dipolar couplings (< 4.5 Hz). Interestingly, the mismatched Hartmann-Hahn condition present in the PMPT experiment gave more intense cross-peaks for lower 1H and 15N spinlock field strengths (32 and 17 kHz, respectively) rather than higher values (55 and 50 kHz), suggesting a more complex magnetization transfer mechanism. Numerical simulations are in good agreement with the experimental findings, suggesting a combined PMPT and CRDSD effect. We conclude that in order to assign SLF spectra and measure short and long-range distances, the combined use of homonuclear correlation spectra, such as the ones surveyed in this work, are necessary.
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影响因子：
15
作者：
Gopinath, T.;Traaseth, Nathaniel J.;Mote, Kaustubh;Veglia, Gianluigi
通讯作者：
Veglia, Gianluigi
影响因子：
15
作者：
Mesleh, MF;Lee, S;Opella, SJ
通讯作者：
Opella, SJ
影响因子：
15
作者：
De Angelis, AA;Nevzorov, AA;Opella, SJ
通讯作者：
Opella, SJ
影响因子：
2.2
作者：
Bertram, R;Asbury, T;Chapman, MS
通讯作者：
Chapman, MS
影响因子：
15
作者：
Lewandowski, Jozef R.;De Paepe, Gael;Griffin, Robert G.
通讯作者：
Griffin, Robert G.