A Small Molecule That Switches a Ubiquitin Ligase From a Processive to a Distributive Enzymatic Mechanism.
A Small Molecule That Switches a Ubiquitin Ligase From a Processive to a Distributive Enzymatic Mechanism.
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DOI：
10.1021/jacs.5b06839
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发表时间：
2015-10-07
影响因子：
15
通讯作者：
Statsyuk AV
中科院分区：
文献类型：
--
作者：
Kathman SG;Span I;Smith AT;Xu Z;Zhan J;Rosenzweig AC;Statsyuk AV
E3连接酶在遗传上与许多人类疾病有关，但E3酶的机制尚未完全了解，并且强烈需要E3的药理学探针。我们报告的发现，HECT E3 Nedd 4 -1是一种进行性酶和生化突变或小分子开关Nedd 4 -1从一个进行性的多聚泛素链合成的分配机制，其持续性中断。此外，我们发现了Nedd 4 -1的第一个共价抑制剂，并对其结构进行了表征，该抑制剂将Nedd 4 -1从进行性机制转换为分布性机制。为了可视化Nedd 4 -1抑制剂的结合模式，我们使用X射线晶体学并解决了与抑制剂结合的Nedd 4 -1家族连接酶的第一个结构。重要的是，我们的研究表明，进行性Nedd 4 -1，而不是分配Nedd 4 -1：抑制剂复合物，能够在去泛素化酶USP 8的存在下在底物上合成聚泛素链。因此，抑制E3连接酶的持续合成能力是设计E3抑制剂的可行策略。我们的研究提供了对HECT E3机制的基本见解，并揭示了一类新的HECT E3抑制剂。
E3 ligases are genetically implicated in many human diseases, yet E3 enzyme mechanisms are not fully understood, and there is a strong need for pharmacological probes of E3s. We report the discovery that the HECT E3 Nedd4-1 is a processive enzyme and that disruption of its processivity by biochemical mutations or small molecules switches Nedd4-1 from a processive to a distributive mechanism of polyubiquitin chain synthesis. Furthermore, we discovered and structurally characterized the first covalent inhibitor of Nedd4-1, which switches Nedd4-1 from a processive to a distributive mechanism. To visualize the binding mode of the Nedd4-1 inhibitor, we used X-ray crystallography and solved the first structure of a Nedd4-1 family ligase bound to an inhibitor. Importantly, our study shows that processive Nedd4-1, but not the distributive Nedd4-1:inhibitor complex, is able to synthesize polyubiquitin chains on the substrate in the presence of the deubiquitinating enzyme USP8. Therefore, inhibition of E3 ligase processivity is a viable strategy to design E3 inhibitors. Our study provides fundamental insights into the HECT E3 mechanism and uncovers a novel class of HECT E3 inhibitors.