Crystal Structure of Classical Swine Fever Virus NS5B Reveals a Novel N-Terminal Domain
Crystal Structure of Classical Swine Fever Virus NS5B Reveals a Novel N-Terminal Domain
复制标题
猪瘟病毒 NS5B 的晶体结构揭示了一个新的 N 端结构域
DOI：
10.1128/jvi.00324-18
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发表时间：
2018-07-01
影响因子：
5.4
通讯作者：
An, Lei
中科院分区：
文献类型：
--
作者：
Li, Weiwei;Wu, Baixing;An, Lei
猪瘟病毒(CSFV)是引起猪瘟的病原。非结构蛋白5B(NS5B)是一种依赖RNA的RNA聚合酶(RdRp)，是通过从头机制启动病毒RNA复制的关键酶。它也是抗猪瘟病毒药物开发的一个有吸引力的靶点。为了更好地了解CSFV RNA合成的机理，我们在这里求解了CSFV NS5B的第一个晶体结构。我们的研究表明，CSFV NS5B RdRp含有特征的手指、手掌和拇指结构域，以及一个从未被观察到的独特的N-末端结构域(NTD)。对NS5B的诱变研究证实了NTD在这种新型RNA依赖的RNA聚合酶催化活性中的重要性。此外，我们的研究结果也为猪瘟病毒的感染提供了理论依据。然而，一种名为猪瘟(CSF)的高度传染性病毒疾病会造成毁灭性的经济损失。猪瘟病毒(CSFV)是黄病毒科害虫病毒属的一种单链正链RNA病毒，是引起猪瘟的主要病原。CSFV的基因组复制依赖于一种被称为NS5B的RNA依赖的RNA聚合酶(RdRp)。然而，CSFV NS5B的结构尚未见报道，对CSFV复制机制也知之甚少。在这里，我们求解了CSFV NS5B的第一个晶体结构，并分析了特征手指、手掌和拇指结构域的功能。此外，我们的结构揭示了一个新的N-末端结构域(NTD)的存在。生化研究表明，CSFV NS5B的NTD对RdRp活性非常重要。总之，我们的研究为未来抗CSFV药物的合理设计提供了结构基础，这一点至关重要，因为还没有开发出有效的抗CSFV药物。
Classical swine fever virus (CSFV) is the cause of classical swine fever (CSF). Nonstructural protein 5B (NS5B) is an RNA-dependent RNA polymerase (RdRp) that is a key enzyme initiating viral RNA replication by a de novo mechanism. It is also an attractive target for the development of anti-CSFV drugs. To gain a better understanding of the mechanism of CSFV RNA synthesis, here, we solved the first crystal structure of CSFV NS5B. Our studies show that the CSFV NS5B RdRp contains the characteristic finger, palm, and thumb domains, as well as a unique N-terminal domain (NTD) that has never been observed. Mutagenesis studies on NS5B validated the importance of the NTD in the catalytic activity of this novel RNA-dependent RNA polymerase. Moreover, our results shed light on CSFV infection.IMPORTANCE Pigs are important domesticated animals. However, a highly contagious viral disease named classical swine fever (CSF) causes devastating economic losses. Classical swine fever virus (CSFV), the primary cause of CSF, is a positive-sense single-stranded RNA virus belonging to the genus Pestivirus, family Flaviviridae. Genome replication of CSFV depends on an RNA-dependent RNA polymerase (RdRp) known as NS5B. However, the structure of CSFV NS5B has never been reported, and the mechanism of CSFV replication is poorly understood. Here, we solve the first crystal structure of CSFV NS5B and analyze the functions of the characteristic finger, palm, and thumb domains. Additionally, our structure revealed the presence of a novel N-terminal domain (NTD). Biochemical studies demonstrated that the NTD of CSFV NS5B is very important for RdRp activity. Collectively, our studies provide a structural basis for future rational design of anti-CSFV drugs, which is critically important, as no effective anti-CSFV drugs have been developed.