The hepatitis E virus (HEV) ORF2 truncated recombinant proteins can self-assemble into virus-like particles (VLPs) and were used as models to investigate the HEV capsid assembly. However, the structural function of the ORF2 C-terminal domain (C52aa from aa 608 to aa 660) remains unclear. Herein, by analyzing a set of ORF2 truncated proteins expressed in Escherichia coli, we found that the highly conserved C-terminal cysteines play a crucial role in the oligomerization of the truncated ORF2 proteins and in their assembly into VLPs, through the formation of dimer-dimer disulfide bonds; and the treatment of native HEV particles with dithiothreitol (DTT) induced the disassembly of the viral capsid, suggesting that the disulfide bonding is required for stabilizing the native HEV capsid. The present study sheds light on the structural role of the C-terminal region of the HEV capsid protein and contributes to the full understating of the viral capsid assembly process.

戊型肝炎病毒（HEV）ORF2截短的重组蛋白可以自组装成病毒样颗粒（VLP），并用作研究HEV衣壳组装的模型。但是，ORF2 C末端域（从aa 608到aa 660的C52aa）的结构功能仍不清楚。本文中，通过分析在大肠杆菌中表达的一组ORF2截短蛋白，我们发现高度保守的C端半胱氨酸在截短的ORF2蛋白质的寡聚化以及通过形成二聚体-二聚体二硫键而组装成VLP中起着至关重要的作用。并且用二硫苏糖醇（DTT）处理天然HEV颗粒会引起病毒衣壳的分解，这表明需要使用二硫键才能稳定天然HEV衣壳。本研究阐明了HEV衣壳蛋白C末端区域的结构作用，并有助于病毒衣壳装配过程的充分低估。