Glutamic acid is a carrier for hydrazine during the biosyntheses of fosfazinomycin and kinamycin

Abstract

Fosfazinomycin and kinamycin are natural products that contain nitrogen–nitrogen (N–N) bonds but that are otherwise structurally unrelated. Despite their considerable structural differences, their biosynthetic gene clusters share a set of genes predicted to facilitate N–N bond formation. In this study, we show that for both compounds, one of the nitrogen atoms in the N–N bond originates from nitrous acid. Furthermore, we show that for both compounds, an acetylhydrazine biosynthetic synthon is generated first and then funneled via a glutamyl carrier into the respective biosynthetic pathways. Therefore, unlike other pathways to N–N bond-containing natural products wherein the N–N bond is formed directly on a biosynthetic intermediate, during the biosyntheses of fosfazinomycin, kinamycin, and related compounds, the N–N bond is made in an independent pathway that forms a branch of a convergent route to structurally complex natural products.