中国生物工程杂志

Bacillus subtilis glutamyl-tRNA reductase encoded by hemA gene as rate-limitation enzyme involved in biosynthesis of 5-ALA that is the precursor of the biosynthesis of terapyrroles as well as an important functional molecular in medical and agricultural application. The hemA gene was polymerase chain reaction amplified from B.subtilis genome DNA and cloned into the expression vector pET28a.The hemA gene was High-level expressed in Escherichia coli BL21(DE3) when induced by IPTG, in which the recombinant protein make up 20% of total soluble protein. We also obtained the purified protein of HemA through the Ni2+-NAT affinity chromatography resin. Biosynthesis level of 5-ALA was enhanced responding to expression of the recombinant protein. The production of 5-ALA reached 40.2mg/L. The catabolite metabolism of 5-ALA porphyrins was also accelerated.