Solution structure and neutralizing antibody binding studies of domain III of the dengue-2 virus envelope protein
Solution structure and neutralizing antibody binding studies of domain III of the dengue-2 virus envelope protein
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DOI：
10.1002/prot.21806
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发表时间：
2008-02-15
影响因子：
2.9
通讯作者：
Cheng, Jya-Wei
中科院分区：
文献类型：
--
作者：
Huang, Kuo-Chun;Lee, Ming-Che;Cheng, Jya-Wei
黄病毒是含有脂质双层膜的小（50 nm）正链RNA病毒。黄病毒科的40种病毒与人类疾病有关，其中大多数通过受感染的蚊子或蜱传播给脊椎动物宿主。1其中，黄热病（YF）、日本脑炎（JE）、蜱传脑炎（TBE）和登革热（DEN）是世界上最重要的病毒性虫媒病毒。DEN病毒感染每年影响超过1亿人口。在过去几十年里，这种疾病的发病率显著增加，死亡率很高。2与其它黄病毒一样，DEN病毒粒子含有3种结构蛋白，即12 kD的核蛋白（C）、8 kD的非糖基化膜蛋白（M）和53 kD的糖基化包膜蛋白（E），以及7种非结构蛋白（NS 1、NS 2A、NS 2B、NS 3、NS 4A、NS 4 B、NS 5）。3 E蛋白是引起中和抗体的优势抗原，在病毒的粘附、融合、穿透、血凝、宿主范围和细胞嗜性、毒力和减毒等方面起重要作用。1通过X射线晶体学测定了DENV-2、DENV-3和TBEV E蛋白的三维结构。4-6 X射线结构显示E蛋白由三个可辨别的结构域组成，结构域I、II和III。JEV、LGTV、WNV和DENV-4包膜蛋白的结构域III的溶液结构最近已被研究。7-11结合DENV结构域III的单克隆抗体被发现是病毒吸附到vero细胞的最有效的阻断剂。12然而，没有提供DENV E蛋白的结构域III的表位的详细空间构型。在这里，我们已经确定了DENV-2 E蛋白的结构域III的溶液结构。此外，我们已经通过定点诱变鉴定了DENV-2结构域III对其特异性中和抗体（mAb 137-22）的中和表位。我们的研究结果提供了一个结构的基础，了解免疫保护机制和合理设计的疫苗有效的DEN病毒。
Flaviviruses are small (50 nm) positive-strand RNA viruses that contain a lipid-bilayer membrane. Forty species of the flavivirus family have been associated with human diseases and most of them are transmitted to their vertebrate hosts by infected mosquitoes or ticks. 1 Among these, yellow fever (YF), Japanese encephalitis (JE), tick-borne encephalitis (TBE), and dengue (DEN) are the most important viral arboviruses in the world. DEN viral infections affect more than 100 million populations per year. There has been a marked increase of this disease over the last decades associated with significant mortality. 2 Like other flaviviruses, the virion of DEN contains three structural proteins—a 12 kD nucleocapsid or core protein (C), a 8 kD nonglycosylated membrane protein (M), and a 53 kD glycosylated envelope protein (E), as well as seven nonstructural proteins (NS1, NS2A, NS2B, NS3, NS4A, NS4B, NS5). 3 The E protein is the dominant antigen in eliciting neutralizing antibodies and plays an important role in viral attachment, fusion, penetration, hemagglutination, host range and cell tropism, and virus virulence and attenuation. 1 The three-dimensional structures of the DENV-2, DENV-3, and TBEV E proteins have been determined by X-ray crystallography. 4–6 The X-ray structures reveal that the E protein is composed of three discernible domains, Domain I, II, and III. The solution structures of the Domain III of JEV, LGTV, WNV, and DENV-4 envelope proteins have been studied recently. 7–11 Monoclonal antibodies that bind to Domain III of DENV are found to be the most efficient blockers of virus adsorption to vero cells. 12 However, no detailed spatial configuration of the epitopes of Domain III of DENV E protein has been provided. In here we have determined the solution structure of the domain III of the DENV-2 E protein. Moreover, we have identified the neutralizing epitopes of the DENV-2 Domain III to its specific neutralization antibody (mAb 137-22) by site-directed mutagenesis. Our results provide a structural basis for understanding the mechanism of immunologic protection and for rational design of vaccines effective against DEN viruses.