Structure of the Fusion Core and Inhibition of Fusion by a Heptad Repeat Peptide Derived from the S Protein of Middle East Respiratory Syndrome Coronavirus
Structure of the Fusion Core and Inhibition of Fusion by a Heptad Repeat Peptide Derived from the S Protein of Middle East Respiratory Syndrome Coronavirus
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DOI：
10.1128/jvi.02433-13
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发表时间：
2013-12-01
影响因子：
5.4
通讯作者：
Gao, George F.
中科院分区：
文献类型：
--
作者：
Gao, Jing;Lu, Guangwen;Gao, George F.
中东呼吸综合征冠状病毒（MERS-CoV）最近成为一个严重的全球公共卫生问题。该病毒具有高致病性，在感染患者中表现出约50%的死亡率。已知冠状病毒的表面刺突（S）蛋白介导受体识别和膜融合，从而在启动感染中发挥不可或缺的作用。在这个过程中，S蛋白的七肽重复序列1和2（HR 1和HR 2）组装成一个称为融合核心的复合物，它代表了一个关键的膜融合结构。然而，迄今为止，MERS-CoV融合核心仍然未被表征。在这项研究中，我们进行了一系列的生化和生物物理分析表征这种新型病毒的HR 1/HR 2复合物。将HR序列截短，然后用柔性氨基酸接头连接。在每种情况下，重组蛋白在溶液中自动组装成三聚体，显示出典型的α-螺旋结构。其中一种三聚体成功结晶，其结构以1.9埃的分辨率解析。一个典型的6螺旋束，像其他冠状病毒报道的那样，被揭示出来，三个HR 1螺旋形成中央卷曲螺旋核心，三个HR 2链围绕核心在HR 1侧槽中。这表明MERS-CoV利用与其他I类包膜病毒相似的机制进行膜融合。有了这个概念，我们进一步确定了一个基于HR 2的肽，可以有效地抑制MERS-CoV融合和进入使用假型病毒系统。这些结果为将来的抑制肽药物设计奠定了基础。
Middle East respiratory syndrome coronavirus (MERS-CoV) recently emerged as a severe worldwide public health concern. The virus is highly pathogenic, manifesting in infected patients with an approximately 50% fatality rate. It is known that the surface spike (S) proteins of coronaviruses mediate receptor recognition and membrane fusion, thereby playing an indispensable role in initiating infection. In this process, heptad repeats 1 and 2 (HR1 and HR2) of the S protein assemble into a complex called the fusion core, which represents a key membrane fusion architecture. To date, however, the MERS-CoV fusion core remains un-characterized. In this study, we performed a series of biochemical and biophysical analyses characterizing the HR1/HR2 complexes of this novel virus. The HR sequences were variably truncated and then connected with a flexible amino acid linker. In each case, the recombinant protein automatically assembled into a trimer in solution, displaying a typical alpha-helical structure. One of these trimers was successfully crystallized, and its structure was solved at a resolution of 1.9 angstrom. A canonical 6-helix bundle, like those reported for other coronaviruses, was revealed, with three HR1 helices forming the central coiled-coil core and three HR2 chains surrounding the core in the HR1 side grooves. This demonstrates that MERS-CoV utilizes a mechanism similar to those of other class I enveloped viruses for membrane fusion. With this notion, we further identified an HR2-based peptide that could potently inhibit MERS-CoV fusion and entry by using a pseudotyped-virus system. These results lay the groundwork for future inhibitory peptidic drug design.