Beijing National Laboratory for Molecular Sciences, Department of Polymer Science and Engineering and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Langmuir. 2022 May 24;38(20):6425-6434. doi: 10.1021/acs.langmuir.2c00580. Epub 2022 May 11.
Although numerous protocell models have been developed to explore the possible pathway of the origin of life on the early earth, few truly fulfill the roles of the DNA/RNA sequence and ATP molecules, which are keys to cell replication and evolution. The ATP-binding aptamer offers an opportunity to combine sequence and energy molecules. In this work, we choose the coacervate droplet as the protocell model and investigate the interaction of the DNA aptamer, poly(l-lysine)(PLL), and ATP under varying conditions. PLL and aptamers form solid precipitates, which spontaneously transform to coacervate droplets as ATP is introduced. The selective uptake and sequestration of exogenous molecules is achieved by the ATP-containing coacervates. As an electric field is applied to expel ATP, the portion of the droplet deficient in ATP becomes solid. The solid/liquid phase ratio is tunable by varying the electric field strength and excitation time. Together with the vacuolization process, a solid head with a soft mouth periodically opening and closing is created. Moreover, the composite coacervate droplet gradually grows as it is treated with an electric field and cannot recover to the original liquid phase after the power is turned off and replenished with ATP. Our work highlights that the proper integration of the DNA sequence, ATP, and energy input could be a powerful strategy for creating a protocell with certain living features.
虽然已经开发出许多原生细胞模型来探索早期地球上生命起源的可能途径，但很少有模型真正能够扮演 DNA/RNA 序列和 ATP 分子的角色，而这两个分子是细胞复制和进化的关键。ATP 结合适体提供了一个将序列和能量分子结合起来的机会。在这项工作中，我们选择凝聚液滴作为原生细胞模型，并研究了在不同条件下 DNA 适体、聚赖氨酸（PLL）和 ATP 之间的相互作用。PLL 和适体形成固体沉淀物，当引入 ATP 时，这些沉淀物会自发转化为凝聚液滴。含有 ATP 的凝聚体可以实现对外源分子的选择性摄取和隔离。当施加电场以排出 ATP 时，缺乏 ATP 的液滴部分会变成固体。通过改变电场强度和激发时间，可以调节固-液相比例。伴随着液泡化过程，形成了一个具有软嘴的固体头部，它会周期性地打开和关闭。此外，复合凝聚液滴在受到电场处理时会逐渐生长，并且在关闭电源并补充 ATP 后，无法恢复到原始的液相。我们的工作强调了 DNA 序列、ATP 和能量输入的适当整合可能是创建具有某些生命特征的原生细胞的一种有力策略。
