Pradimicins T1 and T2, new antifungal antibiotics produced by an actinomycete. II. Structures and biosynthesis.

Pradimicins T1 and T2 are new members of the pradimicin family of antibiotics produced by an actinomycete strain AA3798. Pradimicins T1 and T2 are dihydrobenzo[a]naphthacenequinones substituted with 3 and 2 sugar moieties, respectively. The salient feature in their structures is an L-xylose attached to the phenolic hydroxyl group at C-11. Bioconversion experiments using a blocked mutant B-54 of strain AA3798 not only explored a plausible biosynthetic pathway of pradimicins T1 and T2, but also provided evidence of 5S,6S configuration.