A novel regulatory circuit to control indole biosynthesis protects Escherichia coli from nitrosative damages during the anaerobic respiration of nitrate

摘要: Indole is a widely distributed microbial secondary metabolite. It mediates broad range of physiological processes in both its producing and surrounding species. Yet, indole biosynthesis during the anaerobiosis bacteria remains largely uncharacterized. Here, we find that while production promoted fermentation anaerobic respiration fumarate trimethylamine N-oxide E. coli, repressed nitrate especially exponential growth. We show expression biosynthetic operon tnaCAB under this condition by two component systems NarXL NarPQ global regulator FNR dependent manner. During stationary growth phase respiration, derepressed. However, cellular concentration low. demonstrate due to rapid conversion into mutagenic nitrosative derivatives condition. Consistent with this, supplement exogenous causes elevated mutation frequencies E. coli cells lacking detoxifying efflux genes mdtEF, ectopic over-expression tnaAB decreases fitness coli Together, these results suggest tuned bioenergetics activities facilitate adaptation fitness.