Nature's carbohydrate chemists: The enzymatic glycosylation of bioactive bacterial metabolites

A recent estimate suggests roughly 70% of current lead compounds in modem d rug discovery derive directly from the natural products, many of which are glycosylated bacterial metabolites. Thus, bacterial glycosyltransferases an d their corresponding sugar substrates contribute significantly to the dive rsity of pharmaceutically important metabolites. This review summarizes (i) the role that carbohydrates contribute to biologically active bacterial me tabolites, (ii) a sequence homology classification of known glycosyltransfe rases from these systems and (iii) the potential impact pathway engineering and combinatorial biocatalysis may have on increasing carbohydrate-ligand diversity. While the number of glycosylated bacterial metabolites is vast, this review limits itself to glycosides with considerable published informa tion pertaining to biological activity and biosynthesis.