Faculty of Physics, Southern Federal University, 5 Zorge str., 344090 Rostov-on-Don, Russia.
Nanoscale. 2017 Aug 31;9(34):12449-12460. doi: 10.1039/c7nr04020b.
Viral shells self-assemble from identical proteins, which tend to form equivalent environments in the resulting assembly. However, in icosahedral capsids containing more than 60 proteins, they are enforced to occupy not only the symmetrically equivalent locations but also the quasi-equivalent ones. Due to this important fact, static and dynamic symmetries of viral shells can include additional hidden components. Here, developing the Caspar and Klug ideas concerning the quasi-equivalence of protein environments, we derive the simplest hexagonal tilings, that in principle could correspond to the local protein order in viral shells, and apply the resulting theory to nucleocytoplasmic large dsDNA viruses. In addition, analyzing the dynamic symmetry of the P22 viral shell, we demonstrate that the collective critical modes responsible for the protein reorganization during the procapsid maturation are approximately equivalent to the normal modes of the isotropic spherical membrane with O(3) symmetry. Furthermore, we establish the relationship between the dynamic symmetry of the P22 procapsid and the protein arrangement regularities that appear only in the mature capsid.
病毒外壳由相同的蛋白质自组装而成，这些蛋白质在组装过程中往往形成等效的环境。然而，在含有 60 多种蛋白质的二十面体衣壳中，它们不仅被迫占据对称等效位置，还被迫占据准等效位置。由于这一重要事实，病毒外壳的静态和动态对称性可以包含额外的隐藏成分。在这里，我们发展了 Caspar 和 Klug 关于蛋白质环境准等效性的思想，推导出最简单的六边形平铺，原则上可以对应于病毒外壳中局部蛋白质的顺序，并将所得理论应用于核质大 dsDNA 病毒。此外，分析 P22 病毒外壳的动态对称性，我们证明了负责衣壳成熟过程中蛋白质重组的集体临界模式与各向同性球形膜的 O(3)对称的正常模式大致等效。此外，我们建立了 P22 衣壳的动态对称性与仅在成熟衣壳中出现的蛋白质排列规律之间的关系。
