We provide an experimental and computational framework for ²H quadrupolar chemical exchange saturation transfer NMR experiments (Q‐CEST) under static solid‐state conditions for the quantification of dynamics on μs‐ms timescales. Simulations using simple 2‐site exchange models provide insights into the relation between spin dynamics and motions. Biological applications focus on two sites of amyloid‐β fibrils in the 3‐fold symmetric polymorph. The first site, the methyl group of A2 of the disordered N‐terminal domain, undergoes diffusive motions and conformational exchange due to transient interactions. Earlier ²H rotating frame relaxation and quadrupolar CPMG measurements are combined with the Q‐CEST approach to characterize the multiple conformational states of the domain. The second site, the methyl group of M35, spans the water‐accessible cavity inside the fibrils’ core and undergoes extensive rotameric exchange. Q‐CEST permits us to refine the rotameric exchange model for this site and allows the more precise determination of populations and rotameric exchange rate constants than line shape analysis.

中文翻译：

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用于静态粉末样品的氘核四极化学交换饱和转移 (Q-CEST) 固态 NMR：淀粉样蛋白-β 原纤维的方法和应用。

^{我们为静态固态条件下的2} H 四极化学交换饱和转移 NMR 实验 (Q-CEST)提供了一个实验和计算框架，用于在 μs-ms 时间尺度上量化动力学。使用简单的双位点交换模型进行模拟可以深入了解自旋动力学和运动之间的关系。生物学应用集中于三重对称多晶型物中淀粉样蛋白-β原纤维的两个位点。第一个位点，无序 N 末端结构域 A2 的甲基，由于短暂的相互作用而经历扩散运动和构象交换。早期的² H 旋转框架弛豫和四极 CPMG 测量与 Q-CEST 方法相结合，以表征该域的多种构象状态。第二个位点，M35 的甲基，跨越原纤维核心内的水可进入的空腔，并经历广泛的旋转异构体交换。Q-CEST 允许我们完善该位点的旋转异构体交换模型，并且比线形分析更精确地确定群体和旋转异构体交换率常数。