Frequency-selective homonuclear dipolar recoupling in solid state NMR.
Frequency-selective homonuclear dipolar recoupling in solid state NMR.
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DOI：
10.1063/1.2192516
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发表时间：
2006-05
期刊：
影响因子：
--
通讯作者：
A. Paravastu;R. Tycko
中科院分区：
文献类型：
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作者：
A. Paravastu;R. Tycko
介绍了一种利用魔角自旋（MAS）实现固体核磁共振（NMR）中频率选择性同向偶极重耦合的新方法。这种方法，我们给的首字母缩略词SEASHORE，采用交替周期的双量子再耦合和化学位移的演变，产生相位调制的再耦合偶极-偶极相互作用，平均出不需要的耦合，只留下偶极-偶极耦合之间的核自旋与选定的一对NMR频率。原则上，SEASHORE适用于具有任意耦合强度和任意NMR频率集的系统。任意的MAS频率也是可能的，仅受选择用于双量子再耦合的脉冲序列所施加的限制。我们证明了SEASHORE在均匀（15）N，（13）C-标记的L-缬氨酸粉末中频率选择性极化转移的实验（13）C NMR测量和由含有均匀（15）N，（13）C-标记残基的合成十肽形成的淀粉样蛋白原纤维中频率选择性分子间极化转移的有效性。
We introduce a new approach to frequency-selective homonuclear dipolar recoupling in solid state nuclear magnetic resonance (NMR) with magic-angle spinning (MAS). This approach, to which we give the acronym SEASHORE, employs alternating periods of double-quantum recoupling and chemical shift evolution to produce phase modulations of the recoupled dipole-dipole interactions that average out undesired couplings, leaving only dipole-dipole couplings between nuclear spins with a selected pair of NMR frequencies. In principle, SEASHORE is applicable to systems with arbitrary coupling strengths and arbitrary sets of NMR frequencies. Arbitrary MAS frequencies are also possible, subject only to restrictions imposed by the pulse sequence chosen for double-quantum recoupling. We demonstrate the efficacy of SEASHORE in experimental (13)C NMR measurements of frequency-selective polarization transfer in uniformly (15)N, (13)C-labeled L-valine powder and frequency-selective intermolecular polarization transfer in amyloid fibrils formed by a synthetic decapeptide containing uniformly (15)N, (13)C-labeled residues.