NMR Characterization of Long-Range Order in Intrinsically Disordered Proteins
NMR Characterization of Long-Range Order in Intrinsically Disordered Proteins
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DOI：
10.1021/ja101645g
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发表时间：
2010-06-23
影响因子：
15
通讯作者：
Blackledge, Martin
中科院分区：
文献类型：
--
作者：
Salmon, Loic;Nodet, Gabrielle;Blackledge, Martin
固有无序蛋白(IDPs)被预测为人类基因组的重要组成部分，对这些蛋白进行有意义的分子描述仍然是当代结构生物学的关键挑战。为了描述IDPs的构象行为，需要基于不同来源的结构数据的无序状态的分子表示，这些数据通常表现出复杂和非常不同的平均行为。在这项研究中，我们提出了顺磁驰豫增强(PRES)和剩余偶极耦合(RDC)相结合的方法来定义溶液中IDPs的远程和局部结构特征。我们证明了小行星，一种集合选择算法，即使在存在高度扩散的、定义不清的目标相互作用的情况下，也能忠实地再现分子内的接触。我们还表明，对自旋标记迁移率的显式建模显著改善了实验前数据的再现，即使在高度无序的蛋白质的情况下也是如此。对RDC轮廓的瞬时长程接触影响的预测表明，如果没有正确考虑，分子内弱相互作用会导致轮廓的严重扭曲，从而影响局部构象采样的描述。我们已经为这个问题开发了一种解决方案，包括有效地结合RDC和PRE数据，以同时确定高度灵活的蛋白质的远程和局部结构。这一联合分析被证明对于准确解释a-突触核蛋白的实验数据是必不可少的，a-突触核蛋白是人类神经退行性疾病中的一种重要的IDP，证实了蛋白质中遥远区域之间存在长程有序。
Intrinsically disordered proteins (IDPs) are predicted to represent a significant fraction of the human genome, and the development of meaningful molecular descriptions of these proteins remains a key challenge for contemporary structural biology. In order to describe the conformational behavior of IDPs, a molecular representation of the disordered state based on diverse sources of structural data that often exhibit complex and very different averaging behavior is required. In this study, we propose a combination of paramagnetic relaxation enhancements (PREs) and residual dipolar couplings (RDCs) to define both long-range and local structural features of IDPs in solution. We demonstrate that ASTEROIDS, an ensemble selection algorithm, faithfully reproduces intramolecular contacts, even in the presence of highly diffuse, ill-defined target interactions. We also show that explicit modeling of spin-label mobility significantly improves the reproduction of experimental PRE data, even in the case of highly disordered proteins. Prediction of the effects of transient long-range contacts on RDC profiles reveals that weak intramolecular interactions can induce a severe distortion of the profiles that compromises the description of local conformational sampling if it is not correctly taken into account. We have developed a solution to this problem that involves efficiently combining RDC and PRE data to simultaneously determine long-range and local structure in highly flexible proteins. This combined analysis is shown to be essential for the accurate interpretation of experimental data from a-synuclein, an important IDP involved in human neurodegenerative disease, confirming the presence of long-range order between distant regions in the protein.