Promiscuous Protein Binding as a Function of Protein Stability
Promiscuous Protein Binding as a Function of Protein Stability
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DOI：
10.1016/j.str.2017.11.002
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发表时间：
2017-12-05
期刊：
影响因子：
5.7
通讯作者：
Schreiber, Gideon
中科院分区：
文献类型：
--
作者：
Cohen-Khait, Ruth;Dym, Orly;Schreiber, Gideon
蛋白质已经进化到平衡有效结合所需的伙伴和拒绝不需要的相互作用。为了研究蛋白质-蛋白质相互作用的进化，我们使用酵母表面展示技术随机选择了一个针对野生型TEM1的预稳定TEM1 β -内酰胺酶文库。三个突变足以实现两者之间的微摩尔亲和结合。x射线结构强调，选择突变的主要贡献是修饰蛋白质折叠，特别是去除N'端螺旋，从而允许蛋白质通过β -薄片介导的相互作用偶联，类似于淀粉样蛋白相互作用模式。唯一被选中的突变位于相互作用界面（E58V），与通常引起镰状细胞性贫血的单一突变相似。有趣的是，由于产生的突变蛋白的热稳定性降低，进化的突变不能插入到野生型蛋白中。这些结果揭示了一种简单的机制，通过这种机制，通过热稳定性的丧失来清除不希望的结合。
Proteins have evolved to balance efficient binding of desired partners with rejection of unwanted interactions. To investigate the evolution of protein-protein interactions, we selected a random library of pre-stabilized TEM1 beta-lactamase against wild-type TEM1 using yeast surface display. Three mutations were sufficient to achieve micromolar affinity binding between the two. The X-ray structure emphasized that the main contribution of the selected mutations was to modify the protein fold, specifically removing the N'-terminal helix, which consequently allowed protein coupling via a beta-sheet-mediated interaction resembling amyloid interaction mode. The only selected mutation located at the interaction interface (E58V) is reminiscent of the single mutation commonly causing sickle-cell anemia. Interestingly, the evolved mutations cannot be inserted into the wild-type protein due to reduced thermal stability of the resulting mutant protein. These results reveal a simple mechanism by which undesirable binding is purged by loss of thermal stability.