Manipulation of Cellular Machinery to Produce Anti-cancer Drugs

The nocardioazine natural products are uniquely prenylated and methylated indole alkaloid diketopiperazines (DKPs) that reverse drug resistance of cancer cell lines. We unveiled the nocardioazine biosynthetic pathway from a marine actinomycete, demonstrating that a cyclodipeptide synthase catalyzes cyclo(L-Trp-L-Trp) DKP precursor formation followed by tailoring of this DKP via a novel racemase, prenyltransferase, and methyltransferase to yield nocardioazine B. These results highlight the aptitude of bacteria for chemical synthesis and offer new enzymatic tools for crafting complex organic molecules

Unveiling an indole alkaloid diketopiperazine biosynthetic pathway that features a unique stereoisomerase and multifunctional methyltransferase

Abstract The 2,5-diketopiperazines are a prominent class of bioactive molecules. The nocardioazines are actinomycete natural products that feature a pyrroloindoline diketopiperazine scaffold composed of two D-tryptophan residues functionalized by N- and C-methylation, prenylation, and diannulation. Here we identify and characterize the nocardioazine B biosynthetic pathway from marine Nocardiopsis sp. CMB-M0232 by using heterologous biotransformations, in vitro biochemical assays, and macromolecular modeling. Assembly of the cyclo-L-Trp-L-Trp diketopiperazine precursor is catalyzed by a cyclodipeptide synthase. A separate genomic locus encodes tailoring of this precursor and includes an aspartate/glutamate racemase homolog as an unusual D/L isomerase acting upon diketopiperazine substrates, a phytoene synthase-like prenyltransferase as the catalyst of indole alkaloid diketopiperazine prenylation, and a rare dual function methyltransferase as the catalyst of both N- and C-methylation as the final steps of nocardioazine B biosynthesis. The biosynthetic paradigms revealed herein showcase Nature’s molecular ingenuity and lay the foundation for diketopiperazine diversification via biocatalytic approaches