Bradyrhizobium japonicum produces Δ-aminolevulinic acid, the universal precursor of tetrapyrroles, in a reaction catalyzed by the product of the hemA gene. Expression of the B. japonicum hemA gene is affected by iron availability. Activity of a hemA-lacZ fusion is increased approximately threefold by iron, and RNA analysis indicates that iron regulation is at the level of mRNA accumulation. To our knowledge, this is the first example of an iron-regulated heme biosynthetic gene in prokaryotes.
All Science Journal Classification (ASJC) codes
- Molecular Biology