A role for Dps ferritin activity in long-term survival of Escherichia coli

Abstract

Iron is a crucial cofactor for many enzymatic processes; however, it can be toxic due to its role in Fenton chemistry and production of reactive oxygen species (ROS). E. coli encodes three differentially expressed iron detoxifying and storage proteins, the ferritins FtnA, Bfr, and Dps, that contribute to maintaining iron homeostasis. While the distinct roles for each ferritin remain poorly elucidated, Dps is postulated to account for the majority of iron storage in stationary phase and later due to its abundance in stationary phase cells. Furthermore, its use of hydrogen peroxide as its preferred oxidant is hypothesized to help modulate the deleterious effects of intracellular iron and ROS production. Given that virtually all bacteria encode at least one dps homolog and most microbes in nature frequently experience a state akin to long-term stationary phase, the data presented here support a model in which Dps plays a fundamental role in long-term bacterial iron homeostasis and survival.