Physiological responses of Saccharopolyspora erythraea towards perturbation of intracellular ATP

Saccharopolyspora erythraea is used for industrial-scale production of erythromycin. To explore the physiological role of co-factors in regulation of primary and secondary metabolism of S. erythraea, we initially overexpressed the endogenous F1-ATPase in an erythromycin high-producing strain, E3. The engineered strain is named EA. The F1-ATPase expression resulted in a lower [ATP]/[ADP] ratio, which was accompanied by a dramatic increased production of a reddish pigment and a decreased erythromycin production. Transcriptional analysis revealed that the intracellular [ATP]/[ADP] ratio appeared to exert a global regulation on the metabolism of S.erythraea, and the lower [ATP]/[ADP] ratio induced physiological changes to restore the energy balance, mainly via pathways that tend to produce ATP or NADH. The results also indicated a state of redox stress in the engineered strain, which was correlated to the alteration of electron transport at the branch of the terminal oxidases. Overall design: mRNA profiles of S.erythraea harvested at early exponential phase and at the end of exponential phase were sequenced in duplicate for both the parental strain E3 and the engineered strain EA.