Fig. 1

a Biosynthetic gene cluster and b structures of auroramycin, its analogs produced in this study, along with structurally related polyene macrolactams, incednine and silvalactam. The different gene manipulations on the BGC are annotated by *. Blue * for promoter insertion, red * for site mutation and black * for in-frame gene deletion. Operons for the various biosynthetic pathways are also annotated and color-coded; red is for glycosylation and sugar biosynthesis pathways, green is for extender unit biosynthesis, blue is for polyketide synthases and purple is for starter unit biosynthesis. The gene table corresponding to the gene cluster is also available as Additional file 1: Table S1 and detailed biosynthetic schemes can be found in [6]