The bacterial respiratory electron transport system (ETS) is branched to allow condition-specific modulation of energy metabolism. There is a detailed understanding of the structural and biochemical features of respiratory enzymes; however, a holistic examination of the system and its plasticity is lacking. Here we generate four strains of Escherichia coli harboring unbranched ETS that pump 1, 2, 3, or 4 proton(s) per electron and characterized them using a combination of synergistic methods (adaptive laboratory evolution, multi-omic analyses, and computation of proteome allocation). We report that: (a) all four ETS variants evolve to a similar optimized growth rate, and (b) the laboratory evolutions generate specific rewiring of major energy-generating pathways, coupled to the ETS, to optimize ATP production capability. We thus define an Aero-Type System (ATS), which is a generalization of the aerobic bioenergetics and is a metabolic systems biology description of respiration and its inherent plasticity.

细菌呼吸电子传递系统 (ETS) 是分支的，以允许特定条件下的能量代谢调节。详细了解呼吸酶的结构和生化特征；然而，缺乏对该系统及其可塑性的全面检查。在这里，我们生成了四种大肠杆菌菌株含有未分支的 ETS，每个电子泵送 1、2、3 或 4 个质子，并使用协同方法（自适应实验室进化、多组学分析和蛋白质组分配计算）的组合对其进行表征。我们报告说：（a）所有四种 ETS 变体都进化到类似的优化增长率，并且（b）实验室进化产生了与 ETS 耦合的主要能量产生途径的特定重新布线，以优化 ATP 生产能力。因此，我们定义了一个气动系统 (ATS)，它是有氧生物能量学的概括，是对呼吸及其固有可塑性的代谢系统生物学描述。