Scientists push enzyme evolution into...( Work could lead to mass production ...)

Work could lead to mass production of useful plant products

UPTON, NY -- Scientists at the U.S. Department of Energy's Brookhaven National Laboratory have found a way to make a plant enzyme that is 100 times more efficient than similar enzymes found in nature. The research, described in the June 15, 2001 issue of The Journal of Biological Chemistry, offers insight into how enzymes evolve, and may one day lead to methods to boost production of other useful plant products.

"Plants make many valuable compounds, but often in small quantities," says John Shanklin, the lead biologist on the study. Though not the direct focus of Shanklin's work, examples could include medicinal compounds and oils that may be useful as raw materials for industrial processes.

Shanklin suggests that the reason for such poor production in nature is that the enzymes responsible are newly evolved. "That may seem strange, because many people associate evolution with improvement. But when enzymes evolve new functions, they almost always lose efficiency," he says.

Enzymes are proteins that speed up chemical reactions by bringing the reacting molecules together like pieces of a puzzle. Like all proteins, theyre made of chains of building blocks called amino acids, folded in a precise way to give the enzyme its three-dimensional shape.

In nature, new enzymes arise from random mutations in the genes that code for the amino-acid sequence. Most changes have no effect. A very small percentage improve the enzyme or give it a new function. But more often the changes deform the enzyme, making it ineffective or unstable, Shanklin says. Over hundreds or even millions of years, natural selection might improve the new enzyme. But Shanklin and his team thought there might be a more direct way. "Could we evolve a better enzyme in the laboratory?" he asked.

The method

Shanklin and fellow Brookhaven biologist Ed Whittle were interested in making a more efficient fat-modi
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Contact: Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350
DOE/Brookhaven National Laboratory
12-Jun-2001