Identification of an unexpected shunt pathway product provides new insights into tirandamycin biosynthesis

Abstract

Tirandamycin K (7), the first linear 7,13;9,13-diseco-tirandamycin derivative, was isolated from the tamI (encoding the TamI P450 monooxygenase) disruption mutant strain (ΔtamI) of marine Streptomyces sp. 307–9. Its chemical structure with relative and absolute configurations was elucidated by a combination of extensive spectroscopic analyses and biosynthetic inferences. Structural elucidation of this unusual compound provides new insights into tirandamycin biosynthesis. Moreover, examination of the biological activity of 7 confirms the essential function of the bicyclic ketal ring for antibiotic activities of tirandamycins.