Biosynthesis of Quinolidomicin, the Largest Known Macrolide of Terrestrial Origin: Identification and Heterologous Expression of a Biosynthetic Gene Cluster over 200 kb.

Quinolidomicin A1 is the largest macrolide compound from terrestrial sources, consisting of a 60-membered ring, and its biosynthetic gene cluster was revealed to be over 200 kb. The gene cluster for quinolidomicin was cloned and heterologously expressed. Confirmation of the product led to a structural revision, in which the hydroxy group in the chromophore moiety of the reported structure was replaced by an amine group.