Research Summary

Understanding the structure and function of rieske non heme oxygenases in eukaryotic systems

Rieske Oxygenases (ROs) are non-heme iron enzymes belonging to the class of oxidoreductases. They are multi-component systems with an oxygenase, reductase, and sometimes a ferredoxin component. The gene encoding this protein is found conserved in bacteria and several animal species. Prokaryotic ROs are well-characterized and used as biocatalyst and in bioremediation. They catalyze a variety of chemical reactions with high substrate specificity, regio- and stereo- selectivity. This property is utilized in the synthesis of chiral intermediate for the drug, crixivan, and small aromatic dye, indigo. However, eukaryotic RO is not studied till date. The primary goal of this project is to elucidate the structure of ROs from three organisms, namely Caenorhabitis elegans, Drosophila melanogaster and Danio rerio. Among this, DAF-36 (from C.elegans) and Nvd (from D.melanogaster) are involved in steroid hormone biosynthetic pathway, primarily in the conversion of cholesterol to 7-dehydro cholesterol. Steroid hormones are essential for the larval development of C. elegans and D.melanogaster. Understanding the structure and function of this enzyme is important as it will help in identifying the step it catalyzes in cholesterol metabolism. The results of these studies will provide the frame work for the development of agonists/antagonists against this pathway as well as providing the information necessary to engineer these enzymes to synthesize steroid hormone analogs in a regio- and stereo- specific fashion.

Figure Legend: A three dimensional model of the cholesterol metabolizing Rieske Oxygenase from C.elegans.