Coexpression of 5-Aminolevulinic Acid Synthase Gene Facilitates Heterologous Production of Thermostable Cytochrome P450, CYP119, in Holo Form in Escherichia coli

Cytochrome P450 enzymes are heme-containing monooxygenases that exhibit potential as biocatalysts for practical applications. The Escherichia coli expression system is frequently used for biocatalyst production; however, heterologous production of hemeproteins in their holo form is difficult due to insufficient heme synthesis by the host. In this study, 5-aminolevulinic acid synthase (ALAS) from Rhodobacter capsulatus is used to accelerate intracellular heme biosynthesis in E.coli; this demonstrates that coexpression of the ALAS gene (ALAS) improves the heterologous production of cytochrome P450, CYP119, from Sulfolobus acidocaldarius. Coexpression of ALAS increased the amount of heterologous CYP119 isolated and the ratio of its holo form. The ratio of holo-CYP119 resulting from the coexpression of ALAS in E.coli was 99%, whereas that from cells expressing CYP119 exclusively was 66%. Coexpression of ALAS is a promising alternative for the efficient heterologous production of hemeproteins by using E.coli.