Biosynthetic pathway toward carbohydrate-like moieties of alnumycins contains unusual steps for C-C bond formation and cleavage.

ABSTRACT: Carbohydrate moieties are important components of natural products, which are often imperative for the solubility and biological activity of the compounds. The aromatic polyketide alnumycin A contains an extraordinary sugar-like 4'-hydroxy-5'-hydroxymethyl-2',7'-dioxane moiety attached via a carbon-carbon bond to the aglycone. Here we have extensively investigated the biosynthesis of the dioxane unit through (13)C labeling studies, gene inactivation experiments and enzymatic synthesis. We show that AlnA and AlnB, members of the pseudouridine glycosidase and haloacid dehalogenase enzyme families, respectively, catalyze C-ribosylation conceivably through Michael-type addition of d-ribose-5-phosphate and dephosphorylation. The ribose moiety may be attached both in furanose (alnumycin C) and p

SUBMITTER: Oja T 

PROVIDER: S-EPMC3341043 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature