Hicks Stephen D, Henley C L
Department of Physics, Cornell University, Ithaca, New York 14853, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2006 Sep;74(3 Pt 1):031912. doi: 10.1103/PhysRevE.74.031912. Epub 2006 Sep 25.
We model the spontaneous assembly of a capsid (a virus' closed outer shell) from many copies of identical units, using entirely irreversible steps and only information local to the growing edge. Our model is formulated in terms of (i) an elastic Hamiltonian with stretching and bending stiffness and a spontaneous curvature, and (ii) a set of rate constants for the addition of new units or bonds. An ensemble of highly irregular capsids is generated, unlike the well-known icosahedrally symmetric viruses, but (we argue) plausible as a way to model the irregular capsids of retroviruses such as HIV. We found that (i) the probability of successful capsid completion decays exponentially with capsid size; (ii) capsid size depends strongly on spontaneous curvature and weakly on the ratio of the bending and stretching elastic stiffnesses of the shell; (iii) the degree of localization of Gaussian curvature (a measure of facetedness) depends heavily on the ratio of elastic stiffnesses.
我们使用完全不可逆的步骤，仅依据生长边缘处的局部信息，对由多个相同单元自发组装成的衣壳（病毒的封闭外壳）进行建模。我们的模型是基于：（i）具有拉伸和弯曲刚度以及自发曲率的弹性哈密顿量，以及（ii）一组用于添加新单元或键的速率常数。生成了一组高度不规则的衣壳，这与众所周知的具有二十面体对称性的病毒不同，但（我们认为）作为一种对诸如HIV等逆转录病毒的不规则衣壳进行建模的方式是合理的。我们发现：（i）成功完成衣壳组装的概率随衣壳大小呈指数衰减；（ii）衣壳大小强烈依赖于自发曲率，而对壳的弯曲和拉伸弹性刚度之比的依赖较弱；（iii）高斯曲率的局部化程度（多面性的一种度量）在很大程度上取决于弹性刚度之比。
