An E. coli-Based Biosynthetic Platform Expands the Structural Diversity of Natural Benzoxazoles.

Benzoxazoles are frequently found in synthetic pharmaceuticals and medicinally active natural products. To facilitate benzoxazole-based drug development, an eco-friendly and rapid platform for benzoxazole production is required. In this study, we have completed the biosynthesis of benzoxazoles in E. coli by coexpressing the minimal set of enzymes required for their biosynthesis. Moreover, by coupling this E. coli-based platform with precursor-directed biosynthesis, we have shown that the benzoxazole biosynthetic system is highly promiscuous in incorporating fluorine, chlorine, nitrile, picolinic, and alkyne functionalities into the scaffold. Our E. coli-based system thus paves the way for straightforward generation of novel benzoxazole analogues through future protein engineering and combinatorial biosynthesis.