Diazo groups are found in a range of natural products that possess potent biological activities. Despite longstanding interest in these metabolites, diazo group biosynthesis is not well understood, in part because of difficulties in identifying specific genes linked to diazo formation. Here we describe the discovery of the gene cluster that produces the o-diazoquinone natural product cremeomycin and its heterologous expression in Streptomyces lividans. We have used stable isotope feeding experiments and in vitro characterization of biosynthetic enzymes to decipher the order of events in this pathway and establish that diazo construction involves latestage N–N bond formation. This work represents the first successful production of a diazocontaining metabolite in a heterologous host, experimentally linking a set of genes with diazo formation.
