Table 2.

Role of iron in bacteria cells

Functions	Examples
Cellular composition	Mycobacterium smegmatis shows decreased DNA and RNA levels under iron-limited conditions Escherichia coli needed iron for the synthesis of the deoxyribotides essential for DNA biosynthesis Bacillus subtilis iron depletion blocks DNA biosynthesis
Metabolism	Production of oxidative metabolism enzymes (i.e.: aconitase) of the tricarboxylic acid (TCA) cycle Cytochromes and non-haem iron electron carriers of the electron transport chain (ETC) Prokaryotic nitrogenase enzyme complex consists of an iron-molybdenum protein and an iron-protein, reduce dinitrogen to ammonia compounds 3-deoxy-D-arabino-heptulosonate-7-phosphate (DAHP) synthase of Escherichia coli that is involved in the aromatic pathway contains one atom of iron
Metabolic products	Many bacteria produce siderophores (i.e.: hydroxamate- and phenolates type) under iron-limited conditions to solubilize and transport iron for survival Aquatic bacteria contain iron in the form of magnetite (Fe3O4) that confers on them magnetotactic features
Enzyme activity	Peroxidases, catalases and certain forms of superoxide dismutase (SOD) that prevent the attack of free radical oxygen species (ROS) depend on iron Glutamate synthase responsible for formation of glutamate from a-ketoglutarate requires iron for it to catalyse the reaction