Stiasny K, Allison S L, Marchler-Bauer A, Kunz C, Heinz F X
Institute of Virology, University of Vienna, Austria.
J Virol. 1996 Nov;70(11):8142-7. doi: 10.1128/JVI.70.11.8142-8147.1996.
The exposure of the flavivirus tick-borne encephalitis (TBE) virus to an acidic pH is necessary for virus-induced membrane fusion and leads to a quantitative and irreversible conversion of the envelope protein E dimers to trimers. To study the structural requirements for this oligomeric rearrangement, the effect of low-pH treatment on the oligomeric state of different isolated forms of protein E was investigated. Full-length E dimers obtained by solubilization of virus with the detergent Triton X-100 formed trimers at low pH, whereas truncated E dimers lacking the stem-anchor region underwent a reversible dissociation into monomers without forming trimers. These data suggest that the low-pH-induced rearrangement in virions is a two-step process involving a reversible dissociation of the E dimers followed by an irreversible formation of trimers, a process which requires the stem-anchor portion of the protein. This region contains potential amphipathic alpha-helical and conserved structural elements whose interactions may contribute to the rearrangements which initiate the fusion process.
黄病毒蜱传脑炎（TBE）病毒暴露于酸性pH值环境是病毒诱导膜融合所必需的，并且会导致包膜蛋白E二聚体定量且不可逆地转化为三聚体。为了研究这种寡聚重排的结构要求，我们研究了低pH处理对不同分离形式的蛋白E寡聚状态的影响。用去污剂Triton X-100溶解病毒获得的全长E二聚体在低pH下形成三聚体，而缺少茎-锚定区域的截短E二聚体则可逆地解离为单体，不形成三聚体。这些数据表明，病毒粒子中低pH诱导的重排是一个两步过程，包括E二聚体的可逆解离，随后是三聚体的不可逆形成，这一过程需要蛋白质的茎-锚定部分。该区域包含潜在的两亲性α-螺旋和保守的结构元件，它们之间的相互作用可能有助于启动融合过程的重排。
