Pletnev Sergei V, Zhang Wei, Mukhopadhyay Suchetana, Fisher Bonnie R, Hernandez Raquel, Brown Dennis T, Baker Timothy S, Rossmann Michael G, Kuhn Richard J
Department of Biological Sciences Purdue University West Lafayette, Indiana 47907.
Department of Molecular and Structural Biochemistry North Carolina State University Raleigh, North Carolina 27695.
Cell. 2001 Apr 6;105(1):127-136. doi: 10.1016/s0092-8674(01)00302-6.
There are 80 spikes on the surface of Sindbis virus arranged as an icosahedral surface lattice. Each spike consists of three copies of each of the glycoproteins E1 and E2. There are two glycosylation sites on E1 and two on E2. These four sites have been located by removal of the glycosylation recognition motifs using site-specific mutagenesis, followed by cryoelectron microscopy. The positions of these sites have demonstrated that E2 forms the protruding spikes and that E1 must be long and narrow, lying flat on the viral surface, forming an icosahedral scaffold analogous to the arrangement of the E glycoprotein in flaviviruses. This arrangement of E1 leads to both dimeric and trimeric intermolecular contacts, consistent with the observed structural changes that occur on fusion with host cell membranes, suggesting a similar fusion mechanism for alpha- and flaviviruses.
辛德毕斯病毒表面有80个刺突，排列成二十面体表面晶格。每个刺突由糖蛋白E1和E2各三个拷贝组成。E1上有两个糖基化位点，E2上也有两个。通过使用位点特异性诱变去除糖基化识别基序，然后进行冷冻电子显微镜观察，确定了这四个位点的位置。这些位点的位置表明，E2形成突出的刺突，而E1必须又长又窄，平躺在病毒表面，形成类似于黄病毒中E糖蛋白排列的二十面体支架。E1的这种排列导致二聚体和三聚体分子间接触，这与观察到的与宿主细胞膜融合时发生的结构变化一致，提示α病毒和黄病毒有相似的融合机制。
