Bending and Puncturing the Influenza Lipid Envelope
Bending and Puncturing the Influenza Lipid Envelope
复制标题
DOI：
10.1016/j.bpj.2010.12.3701
复制
发表时间：
2011-02-02
影响因子：
3.4
通讯作者：
Schaap, Iwan A. T.
中科院分区：
文献类型：
--
作者：
Li, Sai;Eghiaian, Frederic;Schaap, Iwan A. T.
溶酶体、包膜病毒以及突触和分泌囊泡都是天然纳米容器（直径约为 100 nm）的例子，它们特别依赖其脂质双层来保护并与细胞交换其内容物。我们应用了主要基于原子力显微镜和有限元建模的方法，可以精确研究流感病毒脂质包膜的机械特性。通过原子力显微镜尖端施加高达 0.2 nN 的力来探测由 PR8 流感脂质制成的小球形囊泡的机械特性，这导致平均弹性变形高达 20%。使用有限元方法对脂质体变形进行建模，以提取脂质双层的弹性特性。我们发现流感脂质体比凝胶相双层预期的更软并且高度可变形：与之前关于流感脂质不经历主要相变的建议一致，我们观察到流感脂质体的刚度随着温度逐渐而微弱地增加（在一个数量级内）。令人惊讶的是，在大多数情况下，流感脂质体能够承受壁到壁的变形，并且通常需要>1 nN的力来刺穿流感包膜，这与病毒蛋白壳相似。因此，选择高度灵活的脂质包膜可以为病毒基因组提供与坚硬的蛋白质外壳一样有效的保护。
Lysosomes, enveloped viruses, as well as synaptic and secretory vesicles are all examples of natural nanocontainers (diameter approximate to 100 nm) which specifically rely on their lipid bilayer to protect and exchange their contents with the cell. We have applied methods primarily based on atomic force microscopy and finite element modeling that allow precise investigation of the mechanical properties of the influenza virus lipid envelope. The mechanical properties of small, spherical vesicles made from PR8 influenza lipids were probed by an atomic force microscopy tip applying forces up to 0.2 nN, which led to an elastic deformation up to 20%, on average. The liposome deformation was modeled using finite element methods to extract the lipid bilayer elastic properties. We found that influenza liposomes were softer than what would be expected for a gel phase bilayer and highly deformable: Consistent with previous suggestion that influenza lipids do not undergo a major phase transition, we observe that the stiffness of influenza liposomes increases gradually and weakly (within one order of magnitude) with temperature. Surprisingly, influenza liposomes were, in most cases, able to withstand wall-to-wall deformation, and forces >1 nN were generally required to puncture the influenza envelope, which is similar to viral protein shells. Hence, the choice of a highly flexible lipid envelope may provide as efficient a protection for a viral genome as a stiff protein shell.