Fig. 2.

Genetic organization and validation of the gene cluster (tub) for TBN biosynthesis. a Genetic organization of the tub gene cluster. b LC–MS analysis of the target metabolite produced by the recombinants of S. coelicolor M1154. TBN Std, the authentic standard of TBN; WT, the metabolites of the wild type TBN producer S. tubercidicus; M1154/12G4, the metabolites of S. coelicolor M1154 derivative harboring the cosmid 12G4; M1154/pJTU2463b, the metabolites of S. coelicolor M1154 derivative harboring the plasmid pJTU2463b as negative control