Transverse relaxation-optimized spectroscopy (TROSY) for NMR studies of aromatic spin systems in 13C-labeled proteins
Transverse relaxation-optimized spectroscopy (TROSY) for NMR studies of aromatic spin systems in 13C-labeled proteins
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DOI：
10.1021/ja980742g
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发表时间：
1998-07-01
影响因子：
15
通讯作者：
Wüthrich, K
中科院分区：
文献类型：
--
作者：
Pervushin, K;Riek, R;Wüthrich, K
横向弛豫优化光谱 (TROSY) 大大提高了蛋白质中芳香族自旋系统多维 NMR 实验的灵敏度。 TROSY利用了这样一个事实：由于C-13化学位移张量具有较大的各向异性，芳香族C-13-H-1部分中C-13双峰的一个组分的横向弛豫通过偶极-偶极（DD）耦合和化学位移各向异性（CSA）弛豫的干扰而减少。 TROSY 在芳香族自旋系统研究中的全部优势是在目前可用的 500 至 800 MHz 共振频率下获得的。由于 C-13 化学位移是使用恒定时间演化周期记录的，因此相对于相应的常规 NMR 实验，TROSY 的信噪比改进随着分子尺寸的增加而增加，并且可以通过结合使用 H-1 和 C-13 稳态磁化强度进一步显着增强。通过在 C-13 化学位移演化周期期间没有 H-1 解耦记录的实验中选择性观察 C-13 双峰的缓慢弛豫成分，可以得到 4-10 倍的信噪比改善。对于均匀 C-13 标记的 18 kDa 亲环蛋白 A，实现了单个芳香族 C-13-H-1 相关峰的灵敏度增益。提出了一种新的 3D ct-TROSY-HCCH-COSY 实验，该实验将 C-13 核的共振与共价结合的 C-13-H-1 基团的共振相关联，可用于芳香族自旋系统的完整识别。在该方案中，相邻芳香族C-13自旋的化学位移演化被记录在两个间接检测的光谱维度中，从而在不增加延迟数量的情况下获得额外的第三维度。
Transverse relaxation-optimized spectroscopy (TROSY) yields greatly improved sensitivity for multidimensional NMR experiments with aromatic spin systems in proteins. TROSY makes use of the fact that due to the large anisotropy of the C-13 chemical shift tensor, the transverse relaxation of one component of the C-13 doublet in aromatic C-13-H-1 moieties is reduced by interference of dipole-dipole (DD) coupling and chemical shift anisotropy (CSA) relaxation. The full advantage of TROSY for studies of aromatic spin systems is obtained at presently available resonance frequencies from 500 to 800 MHz. Since the C-13 chemical shifts are recorded using a constant-time evolution period, the TROSY improvement in signal-to-noise relative to corresponding conventional NMR experiments increases with increasing molecular size and can be further significantly enhanced by combined use of the H-1 and C-13 steady-state magnetizations.With selective observation of the slowly relaxing component of the C-13 doublets in experiments recorded without H-1 decoupling during the C-13 chemical shift evolution period, a 4-10-foId sensitivity gain for individual aromatic C-13-H-1 correlation peaks was achieved for the uniformly C-13-labeled 18 kDa protein cyclophilin A. A new 3D ct-TROSY-HCCH-COSY experiment is presented, which correlates the resonances of C-13 nuclei with those of covalently bound C-13-H-1 groups and can be applied for complete identification of aromatic spin systems. In this scheme the chemical shift evolution of neighboring aromatic C-13 spins are recorded in two indirectly detected spectral dimensions, so that the additional third dimension is obtained without increase of the number of delays.