Overview of Current Research

 

Summary

The keywords that describe work currently underway include: spectroscopic studies of bioinorganic systems; spectroscopic and theoretical studies of porphyrins and phthalocyanines (porphyrinoids); spectroscopic studies of heme proteins and heme binding proteins from Staphylococcus aureus; metal binding studies of metallothioneins, particularly of copper, arsenic, and mercury binding; mechanistic studies of metal binding in metallothioneins; use of a wide range of spectroscopic tools, including magnetic circular dichroism (MCD), circular dichroism, emission, electrospray ionization mass and NMR techniques. Use of DFT, MOPAC and MM/MD theoretical techniques.

The central theme of all our research is the interaction between metals and ligands mainly in biologically active systems. We study these interactions through spectroscopy, kinetics and theory. Overall our research is in the area of bioinorganic chemistry.

Background

Metals are key components of over 30% of known proteins and enzymes, are the key to photosynthesis, are the central elements in bones, and control nerve and muscle action. Yet the inorganic chemistry of biological processes is in its infancy. This interaction is manifest in the overall metal-dependent structure of the biological molecule, in its electronic structure and subsequent electronic properties, and in the overall functions tuned by the presence of the metal or metals. Nature exploits the properties of metals everywhere for the same range of uses we encounter in metal complexes from the laboratory. The intricate flow of metals through the human physiological system is largely unknown, particularly, the role of metals in neurological chemistry. In all of the vital processes, metals are chaperoned as they pass through membranes, aggregate in cells and establish a delicate metabolic balance that manifests as either illness or good health. The essential role of some toxic metals is now being considered as ever more sensitive tools can be applied to characterize the composition of natural materials. The role of biological metals will play an ever-increasing part of the search for a complete description of how biological processes work. The devastating effects of toxic metals, in the past lead and cadmium, today mercury, and, affecting over 40 million people, arsenic. The study of biological metals involves environmental sciences because all metals play a critical role in the health of the environment as a whole, not just humans. Finally, it is clear that metal-based pharmaceuticals will play an ever more important role.

Our current studies include the aromatic porphyrinoids, metal binding in metallothioneins, and iron acquisition by bacteria. Detailed information regarding these topics is available through our published articles.

We employ a very wide range of spectroscopic and analytical tools, most frequently magnetic circular dichroism, absorption, circular dichroism, emission, and mass spectroscopies. Theoretical studies use DFT, MOPAC and MM techniques. We are keen users of synchrotron-based XAFS data and are associated with the Canadian Light Source in Saskatoon. We have recently begun metal-NMR studies on recently discovered proteins. Proteins are prepared by recombinant techniques and characterized by a range electrospray ionization mass spectrometry and chromatography by each student.

We are funded by the Natural Sciences and Engineering Research Council (NSERC) of Canada and the Academic Development Fund at The University of Western Ontario.

 

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