Biosynthesis of vineomycins A1 and B2

Biosynthetic studies of the antibacterial and antitumor antibiotics vineomycins A1 (1) and B2 (2), produced by Streptomyces matensis subsp. vineus, were carried out by labeling experiments with [1-13C]- and [1,2-18C2]sodium acetate followed by 18C NMR spectroscopy. The results show that the benz[a]anthraquinone chromophore of 1 is derived from a decacetate metabolite with decarboxylation at the carboxyl end and that 2 is formed via C-C bond cleavage of 1. Isolation of rabelomycin from the fermentation broth of the same strain suggests a close biosynthetic relationship among the simple benz[a]anthraquinone antibiotics such as rabelomycin, tetrangomycin, aquayamycin, a C-glycosylated benz[a]anthraquinone, and vineomycins. These biosynthetic data prompted us to reconsider the previously published structure of the antibiotic SS-228Y, which has not been revised.