Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
Soft Matter. 2018 Jan 17;14(3):361-367. doi: 10.1039/c7sm01897e.
Cells can control the assembly and disassembly of membraneless organelles by enzymatic processes, but similar control has not been achieved in vitro yet. Here we develop ATP-based coacervate droplets as artificial membraneless organelles that can be fully controlled by two cooperating enzymes. Droplets can be generated within a minute following the addition of phosphoenolpyruvate as a substrate, and they can be dissolved within tens of seconds by adding glucose as the second substrate. We show how the rates of droplet generation and dissolution can be tuned by varying the enzyme and substrate concentrations, and we support our findings with a kinetic model of the underlying enzymatic reaction network. As all steps of the coacervate droplet life cycle, including nucleation, coarsening, and dissolution, occur under the same reaction conditions, the cycle can be repeated multiple times. In addition, by carefully balancing the rates of both enzymatic reactions, our system can be programmed to either form or dissolve droplets at specified times, acting as a chemical timer.
细胞可以通过酶促过程来控制无膜细胞器的组装和拆卸，但这种类似的控制在体外还没有实现。在这里，我们开发了基于 ATP 的凝聚液滴作为人工无膜细胞器，这些细胞器可以通过两种合作酶完全控制。在添加磷酸烯醇丙酮酸作为底物后，只需一分钟即可生成液滴，而添加葡萄糖作为第二底物后，只需数十秒即可溶解液滴。我们展示了如何通过改变酶和底物浓度来调整液滴生成和溶解的速率，并通过对基础酶反应网络的动力学模型来支持我们的发现。由于凝聚液滴生命周期的所有步骤，包括成核、粗化和溶解，都在相同的反应条件下发生，因此可以重复该循环多次。此外，通过仔细平衡两种酶反应的速率，我们的系统可以被编程为在指定的时间形成或溶解液滴，充当化学定时器。
