Genetic engineering of plants (altering DNA to produce more/less of a certain compound or nutrient) has been old news for a while, but MIT researchers are bringing it back to the forefront. By altering enzymes and substrates in periwinkle plant cells, the group of scientists has been able to produce novel drugs that could ameliorate diseases from hypertension to cancer. The drugs are similar to the ones currently available today, but the plant-produced compounds have the potential to be less toxic and more potent. More from the press release:
O’Connor’s laboratory has studied periwinkle for several years because it produces a variety of alkaloid compounds of pharmacological interest, including vinblastine, a drug commonly used to treat cancers such as Hodgkin’s lymphoma.
Periwinkle also produces serpentines, which have shown promise as anti-cancer agents, and ajmalicine, which is used to treat hypertension. Other plant-produced compounds have shown pharmacological activity but are too toxic for use in humans.
…The current work builds on research O’Connor and grad student Elizabeth McCoy reported two years ago. They found that periwinkle cell cultures could produce novel compounds if fed starting materials slightly different from their normal substrates.
…O’Connor and Runguphan focused on an enzyme involved in an early step of the alkaloid synthesis pathway. The enzyme normally accepts a terpenoid called secologanin and tryptamine, an alkaloid, as substrates.
Another graduate student, Peter Bernhardt, engineered a mutant form of the enzyme that can accept tryptamine with a halogen (such as chlorine or bromine) attached. Runguphan grew genetically engineered plant cell cultures that produce the mutant enzyme and got them to synthesize several compounds that periwinkle plants would normally never produce.
Press release: Chemists engineer plants to produce new compounds
Image: Tissue of a periwinkle plant (Donna Coveney)