Researcher(s)
- Caleb Lawson, Chemical Engineering, University of Delaware
Faculty Mentor(s)
- Mark Blenner, Chemical and Biomolecular Engineering, University of Delaware
- Phil O'Dell, Chemical and Biomolecular Engineering, University of Delaware
Abstract
Monoterpene indole alkaloids (MIAs) constitute a large and diverse class of medicinal compounds that originate from a common biochemical precursor, strictosidine. Vinblastine and vincristine are highlighted examples of MIAs used in chemotherapy. Extracting these compounds from their native plant species requires an inordinate amount of plant material with low yield, creating a complex and insecure market for these products. Producing these compounds through a microbial chassis would provide more efficiency. In the interest of fine-tuning the medicinal properties of MIAs, such as increased potency and permeability, regioselective halogenation of the indole ring is a common strategy. However, synthetic halogenation is generally expensive, lacks regioselectivity and creates hazardous waste streams. The halogenation of tryptophan, a precursor molecule to the MIA pathway, is a method that can introduce a halogen into the strictosidine pathway. This requires a halogenase and flavin reductase. There are multiple enzymes from bacterial origin that have been demonstrated to halogenate tryptophan in bacteria and plants. Similarly, there are multiple amino acid decarboxylases from bacteria that have been shown to catalyze tryptophan to tryptamine. Using the lipid-dense Y. lipolytica in combination with these enzymes could prove to be a reliable way to produce halogenated tryptamines for the strictosidine pathway. To gauge the limits of halogen presence in Y. lipolytica, toxicity experiments will be conducted with varying concentrations of halide salts (NaBr and NaCl) and the corresponding 7-halo-tryptophans. The decarboxylases will then be tested in the presence of each halogenated tryptophan, followed by mass spectroscopy to identify halogenated tryptamine.