Inhibiting Iron Mobilization from Bacterioferritin in Impairs Biofilm Formation Irrespective of Environmental Iron Availability.

Although iron is essential for bacteria, the nutrient presents problems of toxicity and solubility. Bacteria circumvent these problems with the aid of iron storage proteins where Fe is deposited and, when necessary, mobilized as Fe for metabolic requirements. In , Fe is compartmentalized in bacterioferritin (BfrB), and its mobilization as Fe requires specific binding of a ferredoxin (Bfd) to reduce the stored Fe. Blocking the BfrB-Bfd complex leads to irreversible iron accumulation in BfrB and cytosolic iron deprivation. Consequently, given the intracellular iron sufficiency requirement for biofilm development, we hypothesized that blocking the BfrB-Bfd interaction in would impair biofilm development. Our results show that planktonic and biofilm-embedded cells where the BfrB-Bfd complex is blocked exhibit cytosolic iron deficiency, and poorly developed biofilms, even in iron-sufficient culture conditions. These results underscore inhibition of the BfrB-Bfd complex as a rational target to dysregulate iron homeostasis and possibly control biofilms.