A Virus-Binding Hot Spot on Human Angiotensin-Converting Enzyme 2 Is Critical for Binding of Two Different Coronaviruses
A Virus-Binding Hot Spot on Human Angiotensin-Converting Enzyme 2 Is Critical for Binding of Two Different Coronaviruses
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DOI：
10.1128/jvi.02274-10
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发表时间：
2011-06-01
影响因子：
5.4
通讯作者：
Li, Fang
中科院分区：
文献类型：
--
作者：
Wu, Kailang;Chen, Lang;Li, Fang
病毒如何进化以选择其受体蛋白进入宿主细胞令人费解。我们最近确定了 NL63 冠状病毒 (NL63-CoV) 和 SARS 冠状病毒 (SARS-CoV) 受体结合域 (RBD) 的晶体结构，每个受体结合域 (RBD) 与其共同受体人血管紧张素转换酶 2 (hACE2) 复合，并提出 hACE2 上存在病毒结合热点。在这里，我们使用结构引导的生化和功能测定研究了这个假设热点的功能。该热点由被疏水隧道壁包围的盐桥组成。扰乱热点结构的突变对病毒/受体相互作用具有显着影响，揭示了热点结构的关键能量贡献。 NL63-CoV/hACE2界面的隧道结构比SARS-CoV/hACE2界面的隧道结构更紧凑，因此RBD/hACE2结合亲和力会因NL63-CoV突变减少隧道空间或因SARS-CoV突变增加隧道空间而降低。此外，NL63-CoV RBD 通过 SARS-CoV 刺突蛋白抑制 hACE2 依赖性转导，这是热点理论的成功应用，有可能成为针对 SARS-CoV 感染的新抗病毒策略。这些结果表明hACE2热点的结构特征是NL63-CoV和SARS-CoV趋同进化的驱动力之一。
How viruses evolve to select their receptor proteins for host cell entry is puzzling. We recently determined the crystal structures of NL63 coronavirus (NL63-CoV) and SARS coronavirus (SARS-CoV) receptor-binding domains (RBDs), each complexed with their common receptor, human angiotensin-converting enzyme 2 (hACE2), and proposed the existence of a virus-binding hot spot on hACE2. Here we investigated the function of this hypothetical hot spot using structure-guided biochemical and functional assays. The hot spot consists of a salt bridge surrounded by hydrophobic tunnel walls. Mutations that disturb the hot spot structure have significant effects on virus/receptor interactions, revealing critical energy contributions from the hot spot structure. The tunnel structure at the NL63-CoV/hACE2 interface is more compact than that at the SARS-CoV/hACE2 interface, and hence RBD/hACE2 binding affinities are decreased either by NL63-CoV mutations decreasing the tunnel space or by SARS-CoV mutations increasing the tunnel space. Furthermore, NL63-CoV RBD inhibits hACE2-dependent transduction by SARS-CoV spike protein, a successful application of the hot spot theory that has the potential to become a new antiviral strategy against SARS-CoV infections. These results suggest that the structural features of the hot spot on hACE2 were among the driving forces for the convergent evolution of NL63-CoV and SARS-CoV.