Characterization\nof Lomofungin Gene Cluster Enables\nthe Biosynthesis of Related Phenazine Derivatives

Phenazine-based small molecules are nitrogen-containing\nheterocyclic\ncompounds with diverse bioactivities and electron transfer properties\nthat exhibit promising applications in pharmaceutical and electrochemical\nindustries. However, the biosynthetic mechanism of highly substituted\nnatural phenazines remains poorly understood. In this study, we report\nthe direct cloning and heterologous expression of the lomofungin biosynthetic\ngene cluster (BGC) from Streptomyces lomondensis S015. Reconstruction and overexpression of the BGCs in Streptomyces coelicolor M1152 resulted in eight phenazine\nderivatives including two novel hybrid phenazine metabolites, and\nthe biosynthetic pathway of lomofungin was proposed. Furthermore,\ngene deletion suggested that NAD(P)H-dependent oxidoreductase gene <i>lomo14</i> is a nonessential gene in the biosynthesis of lomofungin.\nCytotoxicity evaluation of the isolated phenazines and lomofungin\nwas performed. Specifically, lomofungin shows substantial inhibition\nagainst two human cancer cells, HCT116 and 5637. These results provide\ninsights into the biosynthetic mechanism of lomofungin, which will\nbe useful for the directed biosynthesis of natural phenazine derivatives.