Structure function analysis of synthetic colibactin reveals a unique mutational profile

Certain Enterobacteriaceae strains contain a 54-kb biosynthetic gene cluster (BGC) referred to as pks encoding the biosynthesis of a secondary metabolite, colibactin. Bacteria carrying the pks island possess DNA damaging properties that have been associated with CRC, and generate a specific mutational signature in mammalian cells after infection in vitro. Because prior studies have shown that every biosynthetic gene in the pks cluster is required for genotoxicity, it has been hypothesized that this signature is derived from the DNA damaging effects of colibactin, the end product of the pks biosynthetic scaffold. In this study, we treated the human intestinal epithelial cell line HCT 116 with a synthetic colibactin mimetic (742) or an analogous compound lacking DNA-reactive sites (746). We performed whole-genome sequencing on sub-clonal cell populations to catalogue mutations attributed to this compound