Novel and expanded jadomycins incorporating non-proteogenic amino acids

Jadomycin B is a secondary metabolite produced, in response to stress, by Streptomyces venezuelae ISP5230 grown in nutrient-deprived media. We present definitive electrospray ionization mass spectrometry data identifying a series of novel jadomycins with non-proteogenic amino acids incorporated into the oxazolone ring of the secondary metabolite, and strengthening evidence for the existence of an aldimine intermediate in the biosynthetic pathway. We also demonstrate that the size of the oxazolone ring can be expanded by incorporating β-amino acids.