Data used to generate graphs in Fig 1.

Molecular details of genome packaging are little understood for the majority of viruses. In enteroviruses (EVs), cleavage of the structural protein VP0 into VP4 and VP2 is initiated by the incorporation of RNA into the assembling virion and is essential for infectivity. We have applied a combination of bioinformatic, molecular and structural approaches to generate the first high-resolution structure of an intermediate in the assembly pathway, termed a provirion, which contains RNA and intact VP0. We have demonstrated an essential role of VP0 E096 in VP0 cleavage independent of RNA encapsidation and generated a new model of capsid maturation, supported by bioinformatic analysis. This provides a molecular basis for RNA-dependence, where RNA induces conformational changes required for VP0 maturation, but that RNA packaging itself is not sufficient to induce maturation. These data have implications for understanding production of infectious virions and potential relevance for future vaccine and antiviral drug design.

对于绝大多数病毒而言，基因组包装的分子机制仍有待深入阐明。在肠道病毒（enteroviruses, EVs）中，结构蛋白VP0裂解为VP4与VP2的过程，由组装中的病毒体纳入RNA所触发，且该裂解事件对病毒感染性不可或缺。本研究整合生物信息学、分子生物学与结构生物学手段，解析了组装通路中首个包含RNA与完整VP0的中间态结构——前病毒衣壳（provirion）的高分辨率三维结构。研究证实，VP0蛋白的E096位点在VP0裂解过程中发挥关键作用，且该作用不依赖RNA的衣壳化过程；据此我们提出了全新的衣壳成熟模型，并通过生物信息学分析予以佐证。该模型为RNA依赖性成熟机制提供了分子基础：RNA可诱导VP0成熟所需的构象变化，但仅靠RNA包装本身并不足以触发衣壳成熟过程。上述研究结果为理解感染性病毒粒子的产生机制提供了分子层面的理论依据，同时对未来疫苗研发与抗病毒药物开发具有潜在参考价值。