In order to elucidate the effects of iron uptake regulator gene fur on heme synthesis in Escherichia coli, fur was homogenously overexpressed. The growth, the concentration of iron ions and the changes in heme synthesis and the expression level of key genes in heme synthesis pathway were analyzed. The results showed that the heme content in the original strain under iron limited condition was 2.54 times lower than that under non-iron limited condition. Overexpression of fur inhibited the growth and decreased the concentration of intracellular iron ions. Under non-iron limited condition, the heme content in fur overexpressed strain Eco/pEF decreased by 3.55 times compared with that of the original strain and the heme content in Eco/pEF under iron limited condition increased by 3.10 times compared with that under non-iron limited condition. Overexpression of fur down-regulated hemA, while gltX, hemB and hemC were up-regulated by 4.93, 4.61 and 9.39 times, respectively. Under iron limited condition, hemB and hemG in Eco/pEF were up-regulated by 5.59 and 4.49 times, respectively. Although fur overexpression up-regulated the expression levels of the genes involved in heme synthesis pathway, heme content did not increase significantly. These results provide theoretical support for regulating intracellular heme levels by iron ion uptake.
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