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Monday, 30 August 2004
Understanding the Role of Thiolate Ligation in Nature's Hydroxylating Heme Enzymessummary written by Serena DeBeer George
Michael T. Green, John H. Dawson, and Harry B. Gray
Chloroperoxidase is one of a large class of heme proteins that play important roles in a number of physiological processes, including xenobiotic metabolism, neurological development, blood pressure control, and immune defense. These heme protein systems all have the ability to oxygenate saturated hydrocarbons under ambient conditions, a process which is chemically quite challenging, and hence is also of industrial importance. Recently, extended x-ray absorption fine structure (EXAFS) spectroscopy experiments conducted at SSRL by Michael Green (Pennsylvania State University) and his coworkers have been used to provide the first structural characterization of the oxygen intermediate of chloroperoxidase. The results demonstrate that the intermediate is a protonated ferryl species, which is in contrast to the widely accepted porphyrin-radical cation model. These results have important implications for understanding the mechanism of numerous heme enzymes, and EXAFS is one of the only methods that could provide this type of structural information on the intermediate. |
