Nanoindentation studies of full and empty viral capsids and the effects of capsid protein mutations on elasticity and strength
Nanoindentation studies of full and empty viral capsids and the effects of capsid protein mutations on elasticity and strength
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DOI：
10.1073/pnas.0601744103
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发表时间：
2006-04-18
影响因子：
11.1
通讯作者：
Schmidt, CF
中科院分区：
文献类型：
--
作者：
Michel, JP;Ivanovska, IL;Schmidt, CF
豇豆褪绿斑驳病毒衣壳的弹性特性已通过原子力显微镜纳米压痕测量在 pH 4.8 下进行了检查。已经对 W7 衣壳（空的和含有 RNA 基因组的）、盐稳定突变体的完整衣壳和 subE 突变体的空衣壳进行了研究。完整衣壳比空衣壳更能抵抗压痕，但所有衣壳都具有高弹性。存在初始可逆线性状态，该状态持续到直径的 20% 至 30% 之间变化且施加的力为 0.6-1.0 nN 的压痕；随后，力急剧下降，导致不可逆变形。衣壳蛋白的单点突变增加了衣壳的硬度。将实验与均质弹性厚壳变形的有限元分析计算结果进行比较。这些计算捕获了可逆压痕区域的特征，并允许估计空衣壳的杨氏模量和相对强度。
The elastic properties of capsids of the cowpea chlorotic mottle virus have been examined at pH 4.8 by nanoindentation measurements with an atomic force microscope. Studies have been carried out on W7 capsids, both empty and containing the RNA genome, and on full capsids of a salt-stable mutant and empty capsids of the subE mutant. Full capsids resisted indentation more than empty capsids, but all of the capsids were highly elastic. There was an initial reversible linear regime that persisted up to indentations varying between 20% and 30% of the diameter and applied forces of 0.6-1.0 nN; it was followed by a steep drop in force that is associated with irreversible deformation. A single point mutation in the capsid protein increased the capsid stiffness. The experiments are compared with calculations by finite element analysis of the deformation of a homogeneous elastic thick shell. These calculations capture the features of the reversible indentation region and allow Young's moduli and relative strengths to be estimated for the empty capsids.