Peroxide-dependent oxidative degradation of halophenols catalyzed by heme proteins: From globins to peroxidases

BIOL 250

Robert L. Osborne, osborne@mail.chem.sc.edu1, Michael K. Coggins2, and John H. Dawson, dawson@sc.edu2. (1) Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., GSRC 411, Columbia, SC 29208, (2) Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter St., GSRC 411, Columbia, SC 29208
Halophenols are industrial pollutants that pose both environmental and health hazards. Herein, how a catalytic globin, dehaloperoxidase (DHP) from the marine worm Amphitrite ornata, has evolved to be bi-functional as an oxygen transport protein and a catalyst for halophenol detoxification is discussed. Cloning DHP demonstrates that dehaloperoxidase activity is inherent to the protein. Magnetic circular dichroism spectroscopy revealed the His-ligated active site is more similar to horse heart myoglobin than to horseradish peroxidase, the limiting examples of globin and peroxidase proteins. Rapid scan stopped-flow spectroscopy has been employed to examine the roles of high-valent heme intermediates during the oxidative dehalogenation of halophenols. Additionally, we demonstrate the use of the most versatile heme peroxidase, chloroperoxidase from Caldariomyces fumago, as a potential bioremediation catalyst for the breakdown of toxic haloaromatics. Furthermore, how halophenols interact with oxygen transport proteins, like myoglobin, under conditions of oxidative stress has been examined.
 

Enzymes
4:30 PM-6:30 PM, Wednesday, 13 September 2006 Moscone Center -- Hall D, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Sci-Mix

Division of Biological Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006