Sequence - structure - function paradigm has been revolutionized by the discovery of disordered regions and disordered proteins more than two decades ago. While the definition of rigidity is simple with X-ray structures, the notion of flexibility is linked to high experimental B-factors. The definition of disordered regions is more complex as in these same X-ray structures; it is associated to the position of missing residues. Thus a continuum so seems to exist between rigidity, flexibility and disorder. However, it had not been precisely described. In this study, we used an ensemble of disordered proteins (or regions) and, we applied a structural alphabet to analyse their local conformation. This structural alphabet, namely Protein Blocks, had been efficiently used to highlight rigid local domains within flexible regions and so discriminates deformability and mobility concepts. Using an entropy index derived from this structural alphabet, we underlined its interest to measure these local dynamics, and to quantify, for the first time, continuum states from rigidity to flexibility and finally disorder. We also highlight non-disordered regions in the ensemble of disordered proteins in our study.

中文翻译：

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一种结构熵指数，用于分析固有无序蛋白中的局部构象。

二十多年前，无序区和无序蛋白的发现彻底改变了序列-结构-功能范式。虽然使用X射线结构对刚度的定义很简单，但柔韧性的概念与较高的实验B因子有关。与这些相同的X射线结构一样，无序区域的定义更为复杂。它与遗留残基的位置有关。因此，似乎在刚性，柔韧性和无序性之间存在连续性。但是，尚未对其进行精确描述。在这项研究中，我们使用了无序蛋白质（或区域）的整体，并且应用了结构字母来分析其局部构象。这个结构字母，即蛋白质块，可以有效地用于突出显示柔性区域内的刚性局部区域，从而区分可变形性和可移动性概念。使用从该结构字母得出的熵指数，我们强调了它对测量这些局部动力学的兴趣，并首次量化了从刚度到柔韧性以及最终无序的连续状态。在我们的研究中，我们还突出了无序蛋白集合中的无序区域。