Research Interests
Molybdenum is an essential component of a large number of enzymes with diverse functions. Most molybdenum enzymes catalyze two-electron redox reactions involving the transfer of an oxygen atom between water and substrate. We are using X-ray absorption spectroscopy, in combination with electron paramagnetic resonance spectroscopy and other techniques to provide information upon active site structure and catalytic mechanism of several different molybdenum enzymes.
We are using X-ray absorption spectroscopy to follow the biochemical transformations of toxic elements in vivo and in situ. Elements of particular interest are arsenic and mercury, and the mechanism of their antagonism and synergism with selenium.
Sulfur K-edge X-ray Absorption Spectroscopy of intact biological tissues.
Sulfur is an essential biological element, yet its biochemistry is only partially understood because there are few tools for studying this element in biological systems. Sulfur K X-ray absorption near-edge spectroscopy provides a much needed approach to determining the chemical speciation of sulfur in intact biological specimens.
Development of new X-ray Absorption Spectroscopy experimental and analysis techniques.
Extended X-ray absorption fine structure (EXAFS) spectroscopy is well established as a structural tool for determining radial structures. This program investigates the application of modern EXAFS analysis, including full multiple scattering, together with the use of chemical constraints for determining three dimensional structural information.
X-ray Absorption Spectroscopy Imaging.
X-ray Absorption Spectroscopy Imaging uses a micro-focussed X-ray beam to image specific elements in intact samples. With careful choice of energies this technique can provide chemically specific images.
