Broadband homonuclear correlation spectroscopy driven by combined R2(n)(v) sequences under fast magic angle spinning for NMR structural analysis of organic and biological solids.
Broadband homonuclear correlation spectroscopy driven by combined R2(n)(v) sequences under fast magic angle spinning for NMR structural analysis of organic and biological solids.
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DOI：
10.1016/j.jmr.2013.04.009
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发表时间：
2013-07
影响因子：
2.2
通讯作者：
Polenova, Tatyana
中科院分区：
文献类型：
--
作者：
Hou, Guangjin;Yan, Si;Trebosc, Julien;Amoureux, Jean-Paul;Polenova, Tatyana
关键词：
我们最近描述了一系列适用于快速魔角旋转（MAS）条件下同核相关实验的R2nv驱动自旋扩散（RDSD）光谱实验（《美国化学会志》，2011年，133卷，3943页）。在这些RDSD实验中，由于展宽的二阶旋转共振条件主要由射频场强、相移以及重新引入的偶极耦合大小决定，不同的R2nv序列表现出独特的极化转移行为和不同的重耦合频率带宽。在此，我们提出了一系列改进的R2nv序列，称为组合R2nv驱动（CORD）序列，它们能产生宽带同核偶极重耦合，并使交叉峰强度在整个相关光谱中均匀分布。我们报道了核磁共振实验和数值模拟，结果表明这些CORD自旋扩散序列适用于在广泛的磁场和MAS频率范围内进行宽带重耦合，包括快速MAS条件（νr = 40 kHz及以上）。由于这些CORD序列对偶极截断不太敏感，它们非常适合用于确定长程距离约束，这对于广泛系统的结构表征是必不可少的。利用均匀13C标记的丙氨酸和均匀13C、15N标记的组氨酸，我们表明在快速MAS条件下，CORD序列在宽带频率区域内的极化转移效率通常高于其他现有的自旋扩散脉冲方案。一个89个残基的均匀13C、15N标记的动力蛋白轻链（LC8）蛋白质也被用于证明CORD序列在整个化学位移范围内表现出均匀的高交叉峰强度。
We recently described a family of experiments for R2nv Driven Spin Diffusion (RDSD) spectroscopy suitable for homonuclear correlation experiments under fast MAS conditions (J. Am. Chem. Soc., 133, 2011, 3943). In these RDSD experiments, since the broadened second-order rotational resonance conditions are dominated by the radio frequency field strength and the phase shifts, as well as the size of reintroduced dipolar couplings, the different R2nv sequences display unique polarization transfer behaviors and different recoupling frequency bandwidths. Herein, we present a series of modified R2nv sequences, dubbed COmbined R2nv-Driven (CORD), that yield broadband homonuclear dipolar recoupling and give rise to uniform distribution of cross peak intensities across the entire correlation spectrum. We report NMR experiments and numerical simulations demonstrating that these CORD spin diffusion sequences are suitable for broadband recoupling at a wide range of magnetic fields and MAS frequencies, including fast-MAS conditions (νr = 40 kHz and above). Since these CORD sequences are largely insensitive to dipolar truncation, they are well suited for the determination of long-range distance constraints, which are indispensable for the structural characterization of a broad range of systems. Using U-13C-alanine and U-13C,15N-histidine, we show that under fast-MAS conditions, the CORD sequences display polarization transfer efficiencies within broadband frequency regions that are generally higher than those offered by other existing spin diffusion pulse schemes. A 89-residue U-13C,15N-dynein light chain (LC8) protein has also been used to demonstrate that the CORD sequences exhibit uniformly high cross peak intensities across the entire chemical shift range.
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影响因子：
3.3
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通讯作者：
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影响因子：
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作者：
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