使用动态分子开关调控大肠杆菌生产莽草酸

Using dynamic molecular switches for shikimic acid production in Escherichia coli

摘要:

莽草酸是大肠杆菌合成芳香族氨基酸的中间代谢物，也是抗流感药物“达菲”的重要合成前体。合成莽草酸需要截断莽草酸途径，导致芳香族氨基酸无法合成，因此面临细胞生长受到抑制的问题。使用动态调控策略通过将细胞生长和莽草酸的合成相互分离，可以提高菌株的生产性能。通过使用生长偶联型启动子和降解决定子 (Degrons)，组建动态分子开关。利用该动态分子开关实现细胞生长与莽草酸合成分离，在5 L发酵罐中经过72 h发酵得到了14.33 g/L的莽草酸。结果表明，这种动态分子开关可以通过调控靶蛋白丰度来改变碳流量平衡，使菌株获得更优秀的生产性能。

Abstract:

Shikimic acid is an intermediate metabolite in the synthesis of aromatic amino acids in Escherichia coli and a synthetic precursor of Tamiflu. The biosynthesis of shikimic acid requires blocking the downstream shikimic acid consuming pathway that leads to inefficient production and cell growth inhibition. In this study, a dynamic molecular switch was constructed by using growth phase-dependent promoters and degrons. This dynamic molecular switch was used to uncouple cell growth from shikimic acid synthesis, resulting in the production of 14.33 g/L shikimic acid after 72 h fermentation. These results show that the dynamic molecular switch could redirect the carbon flux by regulating the abundance of target enzymes, for better production.