Protein unfolding as a switch from self-recognition to high-affinity client binding.
Protein unfolding as a switch from self-recognition to high-affinity client binding.
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DOI：
10.1038/ncomms10357
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发表时间：
2016-01-20
影响因子：
16.6
通讯作者：
Jakob U
中科院分区：
文献类型：
--
作者：
Groitl B;Horowitz S;Makepeace KAT;Petrotchenko EV;Borchers CH;Reichmann D;Bardwell JCA;Jakob U
伴侣蛋白Hsp33的应激特异性激活需要中央连接区的展开。这种激活机制表明，伴侣自身的部分展开与其结合其他部分折叠的客户蛋白的能力之间存在有趣的功能关系。然而，确定HSP33与其客户的绑定位置仍然是我们对HSP33的S工作机制的理解的一大空白。通过在体内交联研究指导下的位点特异性氟-19核磁共振实验，我们现在揭示了HSP33‘S连接区的部分展开促进了客户与HSP33上的两亲性对接表面的结合。此外，我们的结果为条件性无序区域直接参与未折叠蛋白结合提供了实验证据。所观察到的HSP33的S亚稳连接区与客户蛋白之间的结构相似性为HSP33如何利用蛋白质展开作为从自我识别到高亲和力客户结合的开关提供了一个可能的模型。在应激条件下，分子伴侣Hsp33被激活以处理未折叠的蛋白质。在这里，作者使用体内和体外交联法和19F-核磁共振来阐明错误折叠蛋白质的结合部位，并能够提出其作用机制的模型。
Stress-specific activation of the chaperone Hsp33 requires the unfolding of a central linker region. This activation mechanism suggests an intriguing functional relationship between the chaperone's own partial unfolding and its ability to bind other partially folded client proteins. However, identifying where Hsp33 binds its clients has remained a major gap in our understanding of Hsp33's working mechanism. By using site-specific Fluorine-19 nuclear magnetic resonance experiments guided by in vivo crosslinking studies, we now reveal that the partial unfolding of Hsp33's linker region facilitates client binding to an amphipathic docking surface on Hsp33. Furthermore, our results provide experimental evidence for the direct involvement of conditionally disordered regions in unfolded protein binding. The observed structural similarities between Hsp33's own metastable linker region and client proteins present a possible model for how Hsp33 uses protein unfolding as a switch from self-recognition to high-affinity client binding. Under stress conditions the molecular chaperone Hsp33 is activated to process unfolded proteins. Here, the authors use in vivo and in vitro crosslinking and 19F-NMR to elucidate the binding site for misfolded proteins and are able to propose a model for its mechanism of action.