New Enzyme Discovery Suggests Evolutionary Process

Menlo Park, CA
Monday, December 8, 2003

By manipulating enzymes scientists believe they can shed considerable light into the process of evolution, according to a study discussed in the Dec. 8 issue of Chemical & Engineering News. The study, conducted by researchers from the University of Illinois, Urbana- Champaign, was originally published in Biochemistry. C&EN, a weekly newsmagazine, and Biochemistry, are both published by the American Chemical Society, the world's largest scientific society.

John A. Gerlt of the University of Illinois, Urbana-Champaign and Jeremy Minshull, formerly of Maxygen conducted the research. By changing one amino acid, Gerlt and Minshull enabled an enzyme that catalyzed (sped up) only one reaction to catalyze two. Enzymes are specialized proteins, or strings of amino acids, that perform the body's biological reactions. They have always been thought to be specific and efficient laborers, according to C&EN, but some enzymes been shown to start more than one specific reaction.

This enzyme flexibility, known as "enzyme promiscuity", suggested an interesting evolutionary pathway, the newsmagazine said. If enzyme A - primarily devoted to reaction A - also could start reaction B, that may predict an evolutionary pathway to an enzyme B. The DNA mutations required to change one enzyme to another seemed too many and too random, according to other researchers, C&EN reported. However, Gerlt and Minshull say they have shown otherwise. By changing just one amino acid, Gerlt and Minshull were able to induce promiscuity in a previously loyal enzyme according to their 2003 paper.

A single mutation that induces promiscuity could have resounding effects. It "simplifies nature's problem of catalyzing new catalysts," Gerlt suggests. Such a mutation implies that both promiscuous and genetically near-promiscuous enzymes can be a springboard for evolution.

C&EN also suggests this research is valuable for scientists hoping to create new enzymes. They may find existing enzymes that already catalyze a given reaction as a secondary effect. Finding these promiscuous enzymes, will take them half way to their goal of developing new enzymes to aid in organic synthesis.

SUMMARY: In a study published earlier this year scientists from the University of Illinois, Urbana- Champaign announced an enzyme manipulation that sheds considerable light on the process of evolution. By changing one amino acid, the two researchers enabled an enzyme that catalyzed only one reaction to catalyze two.

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