The Stem Region of Premembrane Protein Plays an Important Role in the Virus Surface Protein Rearrangement during Dengue Maturation
The Stem Region of Premembrane Protein Plays an Important Role in the Virus Surface Protein Rearrangement during Dengue Maturation
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DOI：
10.1074/jbc.m112.384446
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发表时间：
2012-11-23
影响因子：
4.8
通讯作者：
Lok, Shee-Mei
中科院分区：
文献类型：
--
作者：
Zhang, Qian;Hunke, Cornelia;Lok, Shee-Mei
新组装的登革热病毒(DENV)经过成熟成为具有感染性的颗粒。成熟过程包括病毒表面前膜(PRM)和包膜(E)蛋白的主要重排。未成熟病毒表面的PrM-E复合体首先在内质网的中性pH环境中组装成三聚体尖峰。当病毒被运送到外体的低pH环境中时，这些刺突重新排列成与病毒脂膜平行的二聚体结构。参与驱动这一过程的蛋白质尚不清楚。以往对成熟DENV的冷冻电子显微镜研究表明，PRM-茎区域(残基111-131)是膜相关的，可能与E蛋白相互作用。在这里，我们研究了PRM-茎区域在调节病毒成熟过程中的作用。ELISA和表面等离子体共振研究表明，与中性pH相比，低pH条件下PRM-茎区域与E蛋白的结合显著增加。此外，荧光相关光谱分析表明，当pH降低时，PRM-茎区域对脂质体的亲和力也增加。这些结果表明，在外切体的低pH环境中，PRM-茎区域与病毒膜形成紧密的结合，并吸引相关的E蛋白。这将导致在成熟过程中观察到的表面蛋白质重排。
Newly assembled dengue viruses (DENV) undergo maturation to become infectious particles. The maturation process involves major rearrangement of virus surface premembrane (prM) and envelope (E) proteins. The prM-E complexes on immature viruses are first assembled as trimeric spikes in the neutral pH environment of the endoplasmic reticulum. When the virus is transported to the low pH environment of the exosomes, these spikes rearrange into dimeric structures, which lie parallel to the virus lipid envelope. The proteins involved in driving this process are unknown. Previous cryoelectron microscopy studies of the mature DENV showed that the prM-stem region (residues 111-131) is membrane-associated and may interact with the E proteins. Here we investigated the prM-stem region in modulating the virus maturation process. The binding of the prM-stem region to the E protein was shown to increase significantly at low pH compared with neutral pH in ELISAs and surface plasmon resonance studies. In addition, the affinity of the prM-stem region for the liposome, as measured by fluorescence correlation spectroscopy, was also increased when pH is lowered. These results suggest that the prM-stem region forms a tight association with the virus membrane and attracts the associated E protein in the low pH environment of exosomes. This will lead to the surface protein rearrangement observed during maturation.