Fig. 1: Representative macrolide biosynthetic pathways.

a The late pikromycin/(neo)methymycin biosynthetic pathway in which the glycosyltransferase-mediated sugar attachment precedes the P450-catalyzed hydroxylation. b The partial avermectin biosynthetic pathway with an order of oxidation-glycosylation. c The post-PKS pathway of mycinamicin biosynthesis with staggered monooxygenation and glycosylation steps. The functional groups introduced by P450 are highlighted in red, and the functional groups introduced by glycosyltransferase are highlighted in blue.