Redesign of Polyene Macrolide Glycosylation: Engineered Biosynthesis of 19-(O)-Perosaminyl-Amphoteronolide B

Abstract

Most polyene macrolide antibiotics are glycosylated with mycosamine (3,6-dideoxy-3-aminomannose). In the amphotericin B producer, Streptomyces nodosus, mycosamine biosynthesis begins with AmphDIII-catalysed conversion of GDP-mannose to GDP-4-keto-6-deoxymannose. This is converted to GDP-3-keto-6-deoxymannose, which is transaminated to mycosamine by the AmphDII protein. The glycosyltransferase AmphDI transfers mycosamine to amphotericin aglycones (amphoteronolides). The aromatic heptaene perimycin is unusual among polyenes in that the sugar is perosamine (4,6-dideoxy-4-aminomannose), which is synthesised by direct transamination of GDP-4-keto-6-deoxymannose. Here we use the Streptomyces aminophilus perDII perosamine synthase and perDI perosaminyltransferase genes to engineer biosynthesis of perosaminyl-amphoteronolide B in S. nodosus. Efficient production required a hybrid glycosyltransferase containing an N-terminal region of AmphDI and a C-terminal region of PerDI. This work will assist efforts to generate glycorandomised amphoteronolides for drug discovery.