N-prenylation of tryptophan by an aromatic prenyltransferase from the cyanobactin biosynthetic pathway.

Aromatic prenylation is an important step in the biosynthesis of many natural products and leads to an astonishing diversity of chemical structures. Cyanobactin pathways frequently encode aromatic prenyltransferases that catalyze the prenylation of these macrocyclic and linear peptides. Here we characterized the anacyclamide (acy) biosynthetic gene cluster from Anabaena sp. UHCC-0232. Partial reconstitution of the anacyclamide pathway, heterologous expression and in vitro biochemical characterization of the enzyme demonstrate that the AcyF enzyme encoded in this biosynthetic gene cluster is a Trp N-prenyltransferase. Phylogenetic analysis suggests the monophyletic origin and rapid diversification of the cyanobactin prenyltransferase enzymes and the multiple origins of N-1 Trp prenylation in prenylated natural products. The AcyF enzyme displayed high flexibility towards a range of Trp-containing substrates and represents an interesting new tool for biocatalytic applications.