High levels of structural disorder in scaffold proteins as exemplified by a novel neuronal protein, CASK-interactive protein1
High levels of structural disorder in scaffold proteins as exemplified by a novel neuronal protein, CASK-interactive protein1
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DOI：
10.1111/j.1742-4658.2009.07090.x
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发表时间：
2009-07-01
期刊：
影响因子：
5.4
通讯作者：
Tompa, Peter
中科院分区：
文献类型：
--
作者：
Balazs, Annamaria;Csizmok, Veronika;Tompa, Peter
CASK相互作用蛋白1是一种新近发现的哺乳动物神经元突触后密度蛋白。虽然它的N-末端区域包含几个众所周知的功能结构域，但它的整个C-末端富含脯氨酸的800个氨基酸区域与任何先前表征的蛋白质缺乏可检测的序列同源性。我们使用多种技术对该区域及其三个片段进行结构表征。通过生物信息学预测、圆二色谱、宽谱线和核磁共振氢谱、有限蛋白水解和凝胶.通过层析，我们提供了CASK相互作用蛋白1的整个富含脯氨酸区域是内在无序的证据。我们还发现富含脯氨酸的区域具有生物化学功能，因为它与衔接蛋白Abl-相互作用物-2相互作用。来扩展。由于这种支架蛋白中存在高水平的紊乱，我们收集了74种支架蛋白（也包括称为锚和对接的蛋白），并通过三种不同的算法预测它们的紊乱。我们发现，一个非常高的分数（平均53.6%）的残基落入局部无序和它们的有序结构域连接的连接区，其中大部分是无序的（平均64.5%）。由于这种高频率的紊乱，通常设计的支架蛋白的短球状结构域（平均86个氨基酸）连接较长的接头区域（平均140个氨基酸）和注意到的结合功能，这些区域在CASK相互作用蛋白1和其他蛋白质的研究，我们认为，结构紊乱的区域占主导地位，并发挥关键的识别作用，在支架蛋白。
CASK- interactive protein1 is a newly recognized post- synaptic density protein in mammalian neurons. Although its N- terminal region contains several well- known functional domains, its entire C- terminal proline- rich region of 800 amino acids lacks detectable sequence homology to any previously characterized protein. We used multiple techniques for the structural characterization of this region and its three fragments. By bioinformatics predictions, CD spectroscopy, wide- line and H-1- NMR spectroscopy, limited proteolysis and gel. ltration chromatography, we provided evidence that the entire proline- rich region of CASK- interactive protein1 is intrinsically disordered. We also showed that the proline- rich region is biochemically functional, as it interacts with the adaptor protein Abl- interactor- 2. To extend the. nding of a high level of disorder in this scaffold protein, we collected 74 scaffold proteins ( also including proteins denoted as anchor and docking), and predicted their disorder by three different algorithms. We found that a very high fraction ( 53.6% on average) of the residues fall into local disorder and their ordered domains are connected by linker regions which are mostly disordered ( 64.5% on average). Because of this high frequency of disorder, the usual design of scaffold proteins of short globular domains ( 86 amino acids on average) connected by longer linker regions ( 140 amino acids on average) and the noted binding functions of these regions in both CASK- interactive protein1 and the other proteins studied, we suggest that structurally disordered regions prevail and play key recognition roles in scaffold proteins.