Self-Assembly of an Alphavirus Core-like Particle Is Distinguished by Strong Intersubunit Association Energy and Structural Defects.
Self-Assembly of an Alphavirus Core-like Particle Is Distinguished by Strong Intersubunit Association Energy and Structural Defects.
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甲病毒类核心颗粒的自组装以强亚基间缔合能和结构缺陷为特征。
DOI：
10.1021/acsnano.5b02632
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发表时间：
2015
期刊：
影响因子：
17.1
通讯作者：
Zlotnick,Adam
中科院分区：
文献类型：
--
作者：
Wang,JosephChe-Yen;Chen,Chao;Rayaprolu,Vamseedhar;Mukhopadhyay,Suchetana;Zlotnick,Adam
弱缔合能可以导致均匀的纳米结构：由于亚基不稳定性，缺陷可以退火。当强缔合能导致粒子被捕获缺陷时会发生什么？甲病毒是有包膜病毒，其二十面体核衣壳核心可以独立组装。我们使用最简单的案例系统来研究罗斯河病毒 (RRV) 核心样颗粒 (CLP) 使用纯化的衣壳蛋白和短 DNA 寡聚体的自组装。我们发现衣壳蛋白以高亲和力结合寡聚体，形成装配感受态单元（U）。随后，U 以浓度依赖性组装成 CLP。我们确定，与其他病毒组装系统相比，U-U 成对相互作用非常强（约 -6 kcal/mol）。组装的 RRV CLP 表现出形态均匀，并且采用二十面体对称性的冷冻电镜图像重建产生了 T= 4 结构。然而，CLP 的 2D 类别平均值表明，几乎每个类别都有无序区域。这些结果表明 RRV 病毒粒子中可能存在不规则的核心。为了检验这一假设，我们使用真实的病毒粒子或仅通过计算掩蔽分离的完整病毒粒子的核心来确定 RRV 病毒粒子的 2D 类别平均值。基于病毒粒子的类别平均值是对称的、几何的，并且与图像重建的投影很好地对应。在基于核心的类别平均值中，许多类别中的核心和包膜蛋白是无序的。这些结果表明，即使在表面上有序的病毒中，部分无序的成分也很常见，这是斑块粒子的生物学实现。部分无序复合物的生物学优势可能源于其易于解离和不对称性。
Weak association energy can lead to uniform nanostructures: defects can anneal due to subunit lability. What happens when strong association energy leads to particles where defects are trapped? Alphaviruses are enveloped viruses whose icosahedral nucleocapsid core can assemble independently. We used a simplest case system to study Ross River virus (RRV) core-like particle (CLP) self-assembly using purified capsid protein and a short DNA oligomer. We find that capsid protein binds the oligomer with high affinity to form an assembly competent unit (U). Subsequently, U assembles with concentration dependence into CLPs. We determined that U–U pairwise interactions are very strong (ca. −6 kcal/mol) compared to other virus assembly systems. Assembled RRV CLPs appeared morphologically uniform and cryo-EM image reconstruction with imposed icosahedral symmetry yielded aT= 4 structure. However, 2D class averages of the CLPs show that virtually every class had disordered regions. These results suggested that irregular cores may be present in RRV virions. To test this hypothesis, we determined 2D class averages of RRV virions using authentic virions or only the core from intact virions isolated by computational masking. Virion-based class averages were symmetrical, geometric, and corresponded well to projections of image reconstructions. In core-based class averages, cores and envelope proteins in many classes were disordered. These results suggest that partly disordered components are common even in ostensibly well-ordered viruses, a biological realization of a patchy particle. Biological advantages of partly disordered complexes may arise from their ease of dissociation and asymmetry.