Electron Paramagnetic Resonance is a spectroscopic technique which, in combination with site-directed spin-labeling, provides structural and dynamic information about proteins in conditions similar to those of their physiological environment. The information is sequence-resolved as it is based on probing the local dynamics of a paramagnetic label incorporated as a side chain of a selected amino acid. This technique does not impose a limit on the size of the protein or protein complex, as long as it is amenable to site-directed mutagenesis. Reliable distance distributions between two or more labels (identical or different) can also be obtained. The mean value, width and shape of distance distributions, as well as their dependence upon the state of the protein or interactions with physiological partners, provides insight into order-disorder transitions and the roles of protein flexibility. The main potentialities of the technique are revised and illustrated with examples of proteins for which order-disorder play an important role.

中文翻译：

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EPR的定点旋转标记蛋白：研究结构灵活性的强大工具。

电子顺磁共振是一种光谱技术，结合定点自旋标记，可以在类似于其生理环境的条件下提供有关蛋白质的结构和动态信息。该信息是基于序列解析的，因为它是基于探查并入选定氨基酸的侧链的顺磁标记的局部动力学。该技术不限制蛋白质或蛋白质复合物的大小，只要它适合定点诱变即可。还可以获得两个或多个标签（相同或不同）之间的可靠距离分布。距离分布的平均值，宽度和形状，以及它们对蛋白质状态的依赖性或与生理伴侣的相互作用，提供有关有序-无序过渡和蛋白质灵活性的作用的见解。修订了该技术的主要潜力，并举例说明了有序无序发挥重要作用的蛋白质。