BALMORALMYCIN, A NEW ANGUCYCLINONE, AND 2 RELATED BIOSYNTHETIC SHUNT PRODUCTS CONTAINING A NOVEL RING-SYSTEM

A new angucyclinone, named balmoralmycin (1), was isolated as an inhib itor of protein kinase C-alpha (PKC-alpha) from the Streptomyces strai n P6417. Chemical screening of extracts of the same strain resulted in the detection of two decaketides with unusual structural features (2 and 3). Both compounds belong to a recently described structural class of secondary metabolites which arises from engineered biosynthesis of a recombinant Streptomyces strain. The isolation of compounds of this class from a wild-type strain has never been reported before.