The role of Escherichia coli bacterioferritin in stressed induced conditions

Abstract

Escherichia coli possesses at least two iron storage proteins: FtnA (ferritin) and Bfr (Bacterioferritin). FtnA is shown to be a major iron storage protein in E. coli . Although Bfr resembles the ferritin in many of its structural and functional features, the role of Bfr in E. coli is not clear. The aim of this study was to investigate the role of E. coli Bfr in stress induced conditions. In this study, E. coli bfr - (lacking the chromosomal bfr gene) and E. coli bfr + (the same as the former but containing the E. coli bfr overexpression vector) mutants were used. In order to examine the role of E. coli Bfr in stress induced conditions, E. coli cells were grown in the presence of excess iron. In the case of hydrogen peroxide toxicity, the cells were grown in an agar plate containing hydrogen peroxide discs and the results of toxicity were expressed as the size of the cell death zone. In order to find out whether Bfr supports cell growth under iron and phosphate starvation, the E. coli cells were grown in iron and phosphate depleted media. In E. coli the overproduced Bfr did not support the growth of cells under iron and phosphate deficient conditions. The results showed that overproduced Bfr in E. coli does not contribute to the survival of the cell in iron and phosphate starvation. Furthermore, it does not enhance the resistance of E. coli against iron and hydrogen peroxide toxicity.