MCB Professors Discover Unusual Chemical Reaction

Professor of Microbiology William Metcalf, Associate Professor of Biochemistry Satish Nair, and Affiliate Professor of Biochemistry Wilfred van der Donk have identified and analyzed an iron-containing enzyme involved in a bond-breaking reaction.

With the help of X-ray crystallography, researchers have identified and structurally analyzed an iron-containing enzyme that carries out a tricky bond-breaking reaction. The findings could inspire versatile new catalysts.

Bacteria make phosphinothricin, a natural product widely used as a weed killer, with several unusual steps. One includes the cleavage of a very poorly activated carbon-carbon bond in 2-hydroxyethylphosphonate (HEP), a phosphinothricin precursor.

Because unactivated C–C bonds are tough to break with the known synthetic tool kit, scientists want to understand how this transformation takes place, says chemist Wilfred A. van der Donk of the University of Illinois, Urbana-Champaign, who has been working to understand phosphinothricin biosynthesis. But until now his team "didn't know what kind of enzyme did the job and whether cofactors were required for it to work," he says.

So van der Donk's group joined forces with structural biologist Satish K. Nair and microbiologist William W. Metcalf, both at Illinois. The team has now solved the enzyme's X-ray structure and identified it as a nonheme iron-containing oxygenase (Nature, DOI: 10.1038/nature07972). The enzyme, hydroxyethylphosphonate dioxygenase (HEPD), uses molecular oxygen to cleave the poorly activated C–C bond in HEP. -from Chemical and Engineering News

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June 17, 2009 All News