Side chains possess a broader conformational space (compared to the backbone) and are directly affected by intra- and intermolecular interactions, hence their dynamics and the corresponding NMR relaxation data are more sensitive and informative. Nevertheless, transverse relaxation in [Formula: see text] ([Formula: see text] or [Formula: see text]) spin systems is predominantly non-measurable in uniformly [Formula: see text]-labeled proteins due to cross-correlation effects. In the present publication, we propose a number of pulse sequences for accurate and precise measurement of the dipole-dipole transverse cross-correlated relaxation rate [Formula: see text], which, similarly to [Formula: see text] measurements, provides information about the amplitudes of intramolecular dynamics. The suggested approach has allowed us to circumvent a number of obstacles that were limiting earlier applications of [Formula: see text]: (1) impossibility of transmission of the central component of the triplet of [Formula: see text] group to [Formula: see text]-acquisition via INEPT has been solved by transmission of the averaged signal of "inner" and "outer" components of the triplet; (2) direct recording of the entire triplets resulting in substantial overlap of side chain signals has been replaced by recording of individual singlets with the use of [Formula: see text]-modulated approach and constant-time evolution; (3) low sensitivity has been enhanced via proton acquisition which required special attention to a zero-quantum coherence evolution. The proposed method expands the set of "dynamics sensors" covering protein side chains and substantially improves the quality and the level of detail of experimental data describing dynamic processes in proteins and protein complexes.

中文翻译：

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精确测量偶极子/偶极子横向交叉相关弛豫 [公式：参见文本] 在均匀 [公式：参见文本] 标记的蛋白质的亚甲基和伯胺中。

侧链具有更宽的构象空间（与主链相比）并且直接受到分子内和分子间相互作用的影响，因此它们的动力学和相应的 NMR 弛豫数据更加敏感和信息丰富。然而，由于互相关效应，[公式：参见文本]（[公式：参见文本]或 [公式：参见文本]）自旋系统中的横向弛豫在均匀 [公式：参见文本] 标记的蛋白质中主要是不可测量的. 在本出版物中，我们提出了一些脉冲序列，用于精确测量偶极子-偶极子横向互相关弛豫率 [公式：参见文本]，与 [公式：参见文本] 测量类似，它提供了关于分子内动力学的幅度。建议的方法使我们能够规避一些限制 [公式：参见文本] 早期应用的障碍：(1) [公式：参见文本] 组的三元组的中心组件不可能传输到 [公式：见正文]-通过 INEPT 的采集已通过传输三元组的“内部”和“外部”分量的平均信号来解决；(2) 直接记录导致侧链信号大量重叠的整个三联体已被使用[公式：见文本]-调制方法和恒定时间演化记录单个单峰代替；(3) 通过质子采集增强了低灵敏度，这需要特别注意零量子相干演化。所提出的方法扩展了“动态传感器”的集合