Synthetic biochemistry seeks to engineer complex metabolic pathways for chemical conversions outside the constraints of the cell. Establishment of effective and flexible cell-free systems requires the development of simple systems to replace the intricate regulatory mechanisms that exist in cells for maintaining high-energy cofactor balance. Here we describe a simple rheostat that regulates ATP levels by controlling the flow down either an ATP-generating or non-ATP-generating pathway according to the free-phosphate concentration. We implemented this concept for the production of isobutanol from glucose. The rheostat maintains adequate ATP concentrations even in the presence of ATPase contamination. The final system including the rheostat produced 24.1 ± 1.8 g/L of isobutanol from glucose in 91% theoretical yield with an initial productivity of 1.3 g/L/h. The molecular rheostat concept can be used in the design of continuously operating, self-sustaining synthetic biochemistry systems.

中文翻译：

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分子变阻器维持ATP水平以驱动合成生物化学系统

合成生物化学试图设计复杂的代谢途径，以实现细胞限制以外的化学转化。建立有效而灵活的无细胞系统需要开发简单的系统，以取代细胞中存在的用于维持高能辅因子平衡的复杂调控机制。在这里，我们描述了一种简单的变阻器，该变阻器通过根据游离磷酸盐的浓度控制ATP生成途径或非ATP生成途径的流量来调节ATP的水平。我们实现了从葡萄糖生产异丁醇的这一概念。变阻器即使在ATPase污染的情况下也能保持足够的ATP浓度。包括变阻器的最终系统由葡萄糖产生24.1±1.8 g / L的异丁醇，理论产率为91％，初始生产率为1。3克/升/小时。分子变阻器概念可用于连续运行，自我维持的合成生物化学系统的设计中。