Rotational resonance NMR: separation of dipolar coupling and zero quantum relaxation
Rotational resonance NMR: separation of dipolar coupling and zero quantum relaxation
复制标题
DOI：
10.1016/s1090-7807(03)00083-1
复制
发表时间：
2003-09-01
影响因子：
2.2
通讯作者：
Griffin, RG
中科院分区：
文献类型：
--
作者：
Costa, PR;Sun, BQ;Griffin, RG
旋转共振（R-2）的固态NMR技术已被广泛用于测量包括淀粉样蛋白生成肽和膜蛋白在内的多种化合物中C-13核之间接近5-6埃的距离。从R-2处的含时自旋动力学中提取的距离信息的准确性通常受到估计相关零量子线形参数的准确性的限制。在这里，我们证明了自旋频率相关的磁化交换动力学的测量提供的数据，距离和零量子弛豫参数可以独立地提取。除了提供更准确的距离信息，这种技术允许检查零量子线形，这可以表明偶极耦合位点之间存在相关弛豫或化学位移分布。用这种方法，我们已经分离的偶极耦合和零量子弛豫R-2交换曲线的贡献。因此，我们已经显着提高了两个模型化合物（N-乙酰基-D，L-缬氨酸和甘氨酰甘氨酸）中一对C-13之间的分子内，核间距测量的准确性。HCl），其位于4.6-4.7埃（C）的距离范围内，2003 Elsevier Inc. All rights reserved.
The solid state NMR technique of rotational resonance (R-2) has been used extensively to measure distances approaching 5-6 Angstrom between C-13 nuclei in a variety of compounds including amyloidogenic peptides and membrane proteins. The accuracy of the distance information extracted from the time-dependent spin dynamics at R-2 is often limited by the accuracy with which the relevant zero-quantum lineshape parameters are estimated. Here we demonstrate that measurement of spinning frequency dependent magnetization exchange dynamics provides data from which both distance and zero-quantum relaxation parameters can be extracted independently. In addition to providing more accurate distance information, this technique allows examination of the zero-quantum lineshape, which can indicate the presence of correlated relaxation or chemical shift distributions between dipolar-coupled sites. With this approach we have separated the contribution of dipolar couplings and zero quantum relaxation to R-2 exchange curves. Thus, we have significantly improved the accuracy of the measurement of the intramolecular, internuclear distances between a pair of C-13's in two model compounds (N-acetyl-D,L-valine and glycylglycine . HCl) that lie in the distance range 4.6-4.7 Angstrom (C) 2003 Elsevier Inc. All rights reserved.