TitleGlycosylation of acyl carrier protein-bound polyketides during pactamycin biosynthesis.
Publication TypeJournal Article
Year of Publication2019
AuthorsEida AA, Abugrain ME, Brumsted CJ, Mahmud T
JournalNat Chem Biol
Date Published2019 08
KeywordsBacterial Proteins, Carrier Proteins, Cloning, Molecular, Gene Expression Regulation, Bacterial, Pactamycin, Polyketide Synthases, Polyketides, Protein Binding, Streptomyces

Glycosylation is a common modification reaction in natural product biosynthesis and has been known to be a post-assembly line tailoring process in glycosylated polyketide biosynthesis. Here, we show that in pactamycin biosynthesis, glycosylation can take place on an acyl carrier protein (ACP)-bound polyketide intermediate. Using in vivo gene inactivation, chemical complementation and in vitro pathway reconstitution, we demonstrate that the 3-aminoacetophenone moiety of pactamycin is derived from 3-aminobenzoic acid by a set of discrete polyketide synthase proteins via a 3-(3-aminophenyl)3-oxopropionyl-ACP intermediate. This ACP-bound intermediate is then glycosylated by an N-glycosyltransferase, PtmJ, providing a sugar precursor for the formation of the aminocyclopentitol core structure of pactamycin. This is the first example of glycosylation of a small molecule while tethered to a carrier protein. Additionally, we demonstrate that PtmO is a hydrolase that is responsible for the release of the ACP-bound product to a free β-ketoacid that subsequently undergoes decarboxylation.

Alternate JournalNat Chem Biol
PubMed ID31308531
PubMed Central IDPMC6642016
Grant ListR01 AI129957 / AI / NIAID NIH HHS / United States
R15 GM112068 / GM / NIGMS NIH HHS / United States