Virus Mechanics under Molecular Crowding
Virus Mechanics under Molecular Crowding
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分子拥挤下的病毒力学
DOI：
10.1021/acs.jpcb.0c10947
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Dragnea, Bogdan
中科院分区：
文献类型：
--
作者：
Zeng, Cheng;Scott, Liam;Malyutin, Andrey;Zandi, Roya;Van der Schoot, Paul;Dragnea, Bogdan
病毒借助称为衣壳的保护性蛋白质外壳避免病毒基因组暴露于有害物质。这种保护屏障的第二个作用是，在细胞外高浓度的大分子不能自由地扩散穿过它，因此，在细胞内，甚至可能在细胞外，完整的病毒通常处于渗透胁迫状态。病毒以各种方式应对这种压力。在某些情况下，他们可能会利用它来感染。然而，渗透压对病毒物理性质的影响程度和影响仍然几乎未被探索的单链RNA病毒-最丰富的一类病毒。在这里，我们报告的正义RNA二十面体病毒，雀麦花叶病毒（BMV）的模型系统，如何响应渗透压。具体而言，我们研究了在受控的分子拥挤条件下BMV的机械性能和结构稳定性。我们表明，BMV是机械加强下一个小的外部渗透压，但开始屈服后，阈值压力达到。我们解释了这种机械化学行为的影响的分子拥挤的熵的“呼吸”波动模式的病毒外壳。实验结果与病毒RNA施加一个小的负内部渗透压，对衣壳施加预应力一致。我们的研究结果增加了一个新的调查线时，要考虑解决拥挤的环境中的细胞内的病毒解体的机制。
Viruses avoid exposure of the viral genome to harmful agents with the help of a protective protein shell known as the capsid. A secondary effect of this protective barrier is that macromolecules that may be in high concentration on the outside cannot freely diffuse across it. Therefore, inside the cell and possibly even outside, the intact virus is generally under a state of osmotic stress. Viruses deal with this type of stress in various ways. In some cases, they might harness it for infection. However, the magnitude and influence of osmotic stress on virus physical properties remains virtually unexplored for single-stranded RNA viruses—the most abundant class of viruses. Here, we report on how a model system for the positive-sense RNA icosahedral viruses, brome mosaic virus (BMV), responds to osmotic pressure. Specifically, we study the mechanical properties and structural stability of BMV under controlled molecular crowding conditions. We show that BMV is mechanically reinforced under a small external osmotic pressure but starts to yield after a threshold pressure is reached. We explain this mechanochemical behavior as an effect of the molecular crowding on the entropy of the “breathing” fluctuation modes of the virus shell. The experimental results are consistent with the viral RNA imposing a small negative internal osmotic pressure that prestresses the capsid. Our findings add a new line of inquiry to be considered when addressing the mechanisms of viral disassembly inside the crowded environment of the cell.