K. V. Rajagopalan

Research Abstract

The research in our laboratory deals with the chemistry and biology of enzymes in which the element molybdenum is an essential constituent. Recent studies in the laboratory have led to the discovery and characterization of a novel prosthetic group, called molybdopterin, shown to be present in all Mo-containing enzymes (except nitrogenase) and is intimately involved in the catalytic activity associated with the molybdenum centers of the enzymes. More recently molybdopterin has been shown to be present in tungsten containing enzymes from hyperthermophilic archaea. A human genetic deficiency in which the patients display combined deficiencies of all molybdoenzyme activities and suffer from severe neuropathology leading to childhood death has been characterized as resulting from lesions in the biosynthesis of molybdopterin. Current research is directed at areas such as the pathway of biosynthesis of molybdopterin in bacteria and in humans, structural and chemical aspects of the interaction of molybdopterin with molybdoenzymes, and the use of cloned native and mutant genes of molybdoenzymes in structure-function studies of the Mo ligand field and electron transfer reactions in the enzymes. Many of these studies involve the use of techniques such as UV-Visible, fluorescence, EPR, NMR and laser Raman spectroscopies.