Among the tools of structural biology, NMR spectroscopy is unique in that it not only derives a static three-dimensional structure, but also provides an atomic-level description of the local fluctuations and global dynamics around this static structure. A battery of NMR experiments is now available to probe the motions of proteins and nucleic acids over the whole biologically relevant timescale from picoseconds to hours. Here we focus on one of these methods, relaxation dispersion, which resolves dynamics on the micro- to millisecond timescale. Key biological processes that occur on this timescale include enzymatic catalysis, ligand binding, and local folding. In other words, relaxation-dispersion-resolved dynamics are often closely related to the function of the molecule and therefore highly interesting to the structural biochemist. With an astounding sensitivity of ∼0.5%, the method detects low-population excited states that are invisible to any other biophysical method. The kinetics of the exchange between the ground state and excited states are quantified in the form of the underlying exchange rate, while structural information about the invisible excited state is obtained in the form of its chemical shift. Lastly, the population of the excited state can be derived. This diversity in the information that can be obtained makes relaxation dispersion an excellent method to study the detailed mechanisms of conformational transitions and molecular interactions. Here we describe the two branches of relaxation dispersion, R₂ and R_1ρ, discussing their applicability, similarities, and differences, as well as recent developments in pulse sequence design and data processing.

在结构生物学的工具中，NMR光谱法的独特之处在于它不仅可以得出静态的三维结构，而且还可以提供原子级描述围绕此静态结构的局部涨落和整体动力学的描述。现在可以进行一系列NMR实验，以探测从皮秒到几小时的整个生物学相关时间范围内蛋白质和核酸的运动。在这里，我们重点介绍这些方法之一，即弛豫色散，它可以解决微秒级到毫秒级的动力学问题。在此时间范围内发生的关键生物学过程包括酶催化，配体结合和局部折叠。换句话说，弛豫-分散-分辨动力学通常与分子的功能密切相关，因此对于结构生物化学家而言非常有趣。该方法具有〜0.5％的惊人灵敏度，可检测任何其他生物物理方法都不可见的低种群激发态。基态和激发态之间交换的动力学以潜在的交换速率的形式量化，而有关不可见激发态的结构信息以其化学位移的形式获得。最后，可以得出激发态的总体。可获得的信息的多样性使弛豫分散成为研究构象转变和分子相互作用的详细机理的极好方法。在这里，我们描述了弛豫色散的两个分支，基态和激发态之间交换的动力学以潜在的交换速率的形式量化，而有关不可见激发态的结构信息以其化学位移的形式获得。最后，可以得出激发态的总体。可获得的信息的多样性使弛豫分散成为研究构象转变和分子相互作用的详细机理的极好方法。在这里，我们描述了弛豫色散的两个分支，基态和激发态之间交换的动力学以潜在的交换速率的形式量化，而有关不可见激发态的结构信息以其化学位移的形式获得。最后，可以得出激发态的总体。可获得的信息的多样性使弛豫分散成为研究构象转变和分子相互作用的详细机理的极好方法。在这里，我们描述了弛豫色散的两个分支，可获得的信息的多样性使弛豫分散成为研究构象转变和分子相互作用的详细机理的极好方法。在这里，我们描述了弛豫色散的两个分支，可获得的信息的多样性使弛豫分散成为研究构象转变和分子相互作用的详细机理的极好方法。在这里，我们描述了弛豫色散的两个分支，[R ₂和- [R _1ρ，讨论它们的适用性，共同点和不同点，以及在脉冲序列的设计和数据处理的最新发展。