F.W. Studier, "Protein production by auto-induction in high-density shaking cultures," Protein Express Purif, 41:207-34, 2005. (Cited in 124 papers)
While working on the National Institutes of Health's structural genomics project, William Studier at the Brookhaven National Laboratory devised a method that produced up to 10 times the protein yields of conventional techniques and induced simultaneous expression in Escherichia coli cells.
Studier grew the cells in sync by blocking the entrance of lactose into the cells with glucose until the cells reached a certain growth. Once cells consume the glucose, lactose enters the cells and allows induction of proteins. "It's a great timesaver," Studier says.
"You can manipulate the medium and by doing that change expression level," says Brian Fox from the University of Wisconsin, who uses the auto-induction technique in his work on enzymes. "The original Studier medium is 0.2% weight-to-volume lactose, and about 0.2% to 0.3% weight-to-volume glycerol. We get the best expression at 0.6% lactose and around almost 1% glycerol."
The next step:
James Hartley, director of the protein expression laboratory at the National Cancer Institute, has expressed two dozen different proteins using auto-induction. He says he's working to design an instrument that can auto-induce temperature-dependent protein expression.
|Optical density/culture growth |
(light absorption at 600 nm wavelength)