York Centre for Complex Systems Analysis, University of York, York YO10 5DD, UK.
J Mol Biol. 2011 May 6;408(3):399-407. doi: 10.1016/j.jmb.2011.02.039. Epub 2011 Feb 25.
Single-stranded RNA (ssRNA) viruses, which include major human pathogens, package their genomes as they assemble their capsids. We show here that the organization of the viral genomes within the capsids provides intriguing insights into the highly cooperative nature of the assembly process. A recent cryo-electron microscopy structure of bacteriophage MS2, determined with only 5-fold symmetry averaging, has revealed the asymmetric distribution of its encapsidated genome. Here we show that this RNA distribution is consistent with an assembly mechanism that follows two simple rules derived from experiment: (1) the binding of the MS2 maturation protein to the RNA constrains its conformation into a loop, and (2) the capsid must be built in an energetically favorable way. These results provide a new level of insight into the factors that drive efficient assembly of ssRNA viruses in vivo.
单链 RNA（ssRNA）病毒，包括主要的人类病原体，在组装衣壳时将其基因组包装起来。我们在这里表明，衣壳内病毒基因组的组织为组装过程的高度协作性质提供了有趣的见解。最近使用仅 5 重对称平均确定的噬菌体 MS2 的低温电子显微镜结构揭示了其包裹基因组的不对称分布。在这里，我们表明这种 RNA 分布与组装机制一致，该机制遵循两个简单的规则：（1）MS2 成熟蛋白与 RNA 的结合将其构象约束成环，（2）衣壳必须以有利的方式构建。这些结果为驱动体内 ssRNA 病毒有效组装的因素提供了新的见解。
