Critical Knowledge about Opium's Atomic Structure discovered by Danforth Center Researchers

ST. LOUIS, MO, January 19, 2011 (Press-News.org) The opium poppy, one of mankind's oldest medicinal plants, serves today as the commercial source of the powerful analgesic morphine, from which a variety of analgesics and antitussive alkaloids, such as codeine, are derived by semi-synthesis. Principal Investigators, Dr. Toni Kutchan and Dr. Thomas Smith at The Donald Danforth Plant Science Center collaborated to discover new information about the atomic structure of the medicinal plant that may lead to new advances in plant-based pharmaceuticals. The results of this research are published in the recent article, "The Atomic Structure of Salutaridine reductase from the Opium Poppy Papaver Somniferum," in The Journal of Biological Chemistry.

Kutchan and her team investigate opium's biosynthetic pathway to learn more about how this medicinal plant is able to produce morphine, one of the most frequently used medicines worldwide. Kutchan's research team was able to produce, purify, and crystallize one of the plant's enzymes involved in the production of morphine to better understand, in atomic detail, how these compounds are produced.

"This may be the first time an enzyme from the opium synthetic pathway has been able to be crystallized for these kinds of structural studies," said Kutchan. "Opium may be one of the oldest medicinal plants but we are now discovering more about its pathway to enable the development of alternate sources of known pharmaceuticals and of novel drugs."

Next, Smith and his colleagues used a technique called X-ray crystallography to find the locations of all of the atoms in this enzyme. This information was used to create a model for the enzyme that showed a large flap covering the active site. From this structure and additional evidence, it seems likely that the enzyme acts in a 'pacman' fashion; its mouth opening and closing as the enzyme catalyzes its reaction.

"Understanding how the enzyme works at an atomic level can further our understanding of the complex reactions that the poppy uses to produce opium," said Smith.

The production of opium in poppy is just one example of the extremely complex chemistry that is common in plants. The more details we have as to how plants make such complex products, the more likely it is that we will someday be able to manipulate enzymes to produce new and novel therapeutics.

About The Donald Danforth Plant Science Center
Founded in 1998, the Donald Danforth Plant Science Center is a not-for-profit research institute with a mission to improve the human condition through plant science. Research at the Danforth Center will feed the hungry and improve human health, preserve and renew the environment, and enhance the St. Louis region and Missouri as a world center for plant science. The Center's work is funded through competitive grants and contract revenue from many sources, including the U.S. Department of Energy, National Science Foundation, United States Department of Agriculture, U.S. Agency for International Development and the Bill & Melinda Gates Foundation.