Two and a half years ago, a University of California, Berkeley, team led by Jay D. Keasling, UC Berkeley professor of chemical engineering and bioengineering, succeeded in engineering bacteria to make a chemical precursor of artemisinin - the best drug available today to cure malaria.
The team's ultimate goal was to retool the microbe's metabolism to perform as much of the drug synthesis as possible in order to sidestep the expensive laboratory synthesis needed to make artemisinin. That synthesis would have increased the drug's cost beyond the researchers' ambitious target of 25 cents per dose.
They now have nearly achieved that goal by engineering the production of artemisinic acid, one chemical alteration away from artemisinin. The fact that the researchers have not yet been able to produce artemisinin itself is not a disadvantage, they said, since drugs currently on the market - all made from extracts of the wormwood plant, Artemisia annua - are synthetic derivatives of both artemisinic acid and artemisinin.
"This is probably as close to artemisinin as we are going to get in microbes. The rest is going to be done by chemistry," said Keasling, His lab partnered with the San Francisco-based Institute for OneWorld Health, a nonprofit pharmaceutical company, and Emeryville, Calif.,-based Amyris Biotechnologies in late 2004 on a $43 million grant from the Bill and Melinda Gates Foundation to develop low-cost artemisinin drugs using Keasling's genetically engineered microbes.
A detailed description of the researchers' work appears in the April 13 issue of Nature.
Keasling noted that his team achieved its recent feat in yeast, not E. coli bacteria. Bacteria breed faster and are often the microbes of choice, but the ability to get t
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Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
12-Apr-2006