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Abstract：
Porcine epidemic diarrhea virus (PEDV), an enteropathogenic Alphacoronavirus, has caused enormous economic losses in the pork industry. Nonstructural protein 1 (nsp1) is a characteristic feature of alpha- and betacoronaviruses, which exhibits both functional conservation and mechanistic diversity in inhibiting host gene expression and antiviral responses. However, the detailed structure and molecular mechanisms underlying the Alphacoronavirus nsp1 inhibition of host gene expression remain unclear. Here, we report the first full-length crystal structure of Alphacoronavirus nsp1 from PEDV. The structure displays a six-stranded β-barrel fold in the middle of two α-helices. The core structure of PEDV nsp1 shows high similarity to those of severe acute respiratory syndrome coronavirus (SARS-CoV) nsp1 and transmissible gastroenteritis virus (TGEV) nsp1, despite its low degree of sequence homology. Using ribopuromycylation and Renilla luciferase reporter assays, we showed that PEDV nsp1 can dramatically inhibit general host gene expression. Furthermore, three motifs (amino acids [aa] 67 to 71, 78 to 85, and 103 to 110) of PEDV nsp1 create a stable functional region for inhibiting protein synthesis, differing considerably from Betacoronavirus nsp1. These results elucidate the detailed structural basis through which PEDV nsp1 inhibits host gene expression, providing insight into the development of a new attenuated vaccine with nsp1 modifications.IMPORTANCE Porcine epidemic diarrhea virus (PEDV) has led to tremendous economic losses in the global swine industry. PEDV nsp1 plays a crucial role in inhibiting host gene expression, but its functional mechanism remains unclear. Here, we report the full-length structure of PEDV nsp1, the first among coronaviruses to be reported. The 1.25-Å resolution crystal structure of PEDV nsp1 shows high similarity to severe acute respiratory syndrome coronavirus (SARS-CoV) nsp113-128 and transmissible gastroenteritis virus (TGEV) nsp11-104, despite a lack of sequence homology. Structural and biochemical characterization demonstrated that PEDV nsp1 possesses a stable functional region for inhibition of host protein synthesis, which is formed by loops at residues 67 to 71, 78 to 85, and 103 to 110. The different functional regions in PEDV nsp1 and SARS-CoV nsp1 may explain their distinct mechanisms. Importantly, our structural data are conducive to understanding the mechanism of PEDV nsp1 inhibition of the expression of host genes and may aid in the development of a new attenuated vaccine.
摘要：
猪流行性腹泻病毒(PEDV),一种肠致病性Alphacoronavirus,给猪肉行业造成了巨大的经济损失。非结构蛋白1（nsp1）是α-和β-冠状病毒的特征，在抑制宿主基因表达和抗病毒反应方面表现出功能保守性和机制多样性。然而,Alphacoronavirusnsp1抑制宿主基因表达的详细结构和分子机制尚不清楚.这里,我们报道了来自PEDV的Alphacoronvirusnsp1的第一个全长晶体结构。该结构在两个α-螺旋的中间显示六链β-桶折叠。PEDVnsp1的核心结构显示出与严重急性呼吸综合征冠状病毒（SARS-CoV）nsp1和传染性胃肠炎病毒（TGEV）nsp1的高度相似性，尽管其序列同源性较低。使用肌囊化和Renilla荧光素酶报告基因测定，我们表明PEDVnsp1可以显着抑制一般宿主基因的表达。此外，PEDVnsp1的三个基序（氨基酸[aa]67至71、78至85和103至110）产生了抑制蛋白质合成的稳定功能区，与Betacoronavirusnsp1有很大不同。这些结果阐明了PEDVnsp1抑制宿主基因表达的详细结构基础，提供对具有nsp1修饰的新型减毒疫苗的开发的见解。猪流行性腹泻病毒(PEDV)给全球养猪业造成了巨大的经济损失。PEDVnsp1在抑制宿主基因表达中起着至关重要的作用，但其功能机制尚不清楚。这里,我们报道了PEDVnsp1的全长结构,这是冠状病毒中第一个被报道的.尽管缺乏序列同源性，但PEDVnsp1的1.25-分辨率晶体结构与严重急性呼吸道综合症冠状病毒（SARS-CoV）nsp113-128和传染性胃肠炎病毒（TGEV）nsp11-104具有很高的相似性。结构和生化特征表明，PEDVnsp1具有抑制宿主蛋白合成的稳定功能区域，其由残基67至71、78至85和103至110处的环形成。PEDVnsp1和SARS-CoVnsp1中的不同功能区域可能解释了它们的不同机制。重要的是,我们的结构数据有助于理解PEDVnsp1抑制宿主基因表达的机制，并可能有助于开发新的减毒疫苗。
