Physical Chemistry and Soft Matter, Wageningen University & Research , Stippeneng 4, 6708 WE Wageningen, The Netherlands.
Soft Matter Physics, Huygens-Kamerling Onnes Laboratory, Leiden University , PO Box 9504, 2300 RA Leiden, The Netherlands.
J Am Chem Soc. 2017 Apr 5;139(13):4962-4968. doi: 10.1021/jacs.7b01401. Epub 2017 Mar 28.
The coassembly of well-defined biological nanostructures relies on a delicate balance between attractive and repulsive interactions between biomolecular building blocks. Viral capsids are a prototypical example, where coat proteins exhibit not only self-interactions but also interact with the cargo they encapsulate. In nature, the balance between antagonistic and synergistic interactions has evolved to avoid kinetic trapping and polymorphism. To date, it has remained a major challenge to experimentally disentangle the complex kinetic reaction pathways that underlie successful coassembly of biomolecular building blocks in a noninvasive approach with high temporal resolution. Here we show how macromolecular force sensors, acting as a genome proxy, allow us to probe the pathways through which a viromimetic protein forms capsids. We uncover the complex multistage process of capsid assembly, which involves recruitment and complexation, followed by allosteric growth of the proteinaceous coat. Under certain conditions, the single-genome particles condense into capsids containing multiple copies of the template. Finally, we derive a theoretical model that quantitatively describes the kinetics of recruitment and growth. These results shed new light on the origins of the pathway complexity in biomolecular coassembly.
生物纳米结构的共组装依赖于生物分子构建块之间吸引和排斥相互作用之间的微妙平衡。病毒衣壳就是一个典型的例子，外壳蛋白不仅表现出自相互作用，还与它们包裹的货物相互作用。在自然界中，拮抗和协同相互作用之间的平衡已经进化到可以避免动力学捕获和多态性。迄今为止，如何在不进行侵入性实验的情况下，以高时间分辨率从实验上分离出生物分子构建块成功共组装的复杂动力学反应途径，仍然是一个主要挑战。在这里，我们展示了大分子力传感器如何作为基因组的替代品，来探测病毒模拟蛋白形成衣壳的途径。我们揭示了衣壳组装的复杂多阶段过程，其中涉及到招募和络合，然后是蛋白质外壳的变构生长。在某些条件下，单基因组颗粒凝聚成含有多个模板拷贝的衣壳。最后，我们推导出一个定量描述招募和生长动力学的理论模型。这些结果为生物分子共组装中途径复杂性的起源提供了新的线索。
