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Joanne L. Turnbull, Associate Professor and Chair of the Department of Chemistry and Biochemistry

Education:  B.Sc., University of Saskatchewan (1978); M.Sc., University of Saskatchewan (1982); Ph.D., Australian National University (1989); Post-doctoral Fellow: University of California, Berkeley (1989-1992)

Room: SP 275.05     Laboratory: SP 285.01     E-mail:  jturn@alcor.concordia.ca     Tel: 514.848.2424 x3389       Fax: 514.848.2868

Research Interests - Mechanistic enzymology of aromatic amino acid pathways:

As a mechanistic enzymologists, we are interested in understanding how enzymes catalyze biochemical reactions, with huge rate accelerations over the analogous uncatalyzed reactions. 

What roles are played by the proper positioning and ionization state of key amino acid residues in the enzyme active site?

If the enzyme has more than one activity, what is (are) the nature of the active site(s)?

We have studied the mechanism of action of several different proteins, but our current focus is on enzymes in the shikimate pathway, such as chorismate mutase (1 - 2 - 3) and prephenate dehydrogenase (3 - 4), which are involved in the biosynthesis of the essential aromatic amino acids. These enzymes are potential targets for the development of inhibitors that can act as antimicrobial agents or herbicides. Our studies also involve comparative enzymology between enzymes derived from bacteria that thrive in extremely hot environments (thermophiles) and also those that prefer moderate temperatures (mesophiles). We use the techniques of protein chemistry, mass spectrometry, site-directed mutagenesis, kinetic analysis and biophysical spectroscopy in order to understand the catalytic mechanism of these enzymes and how the structures of the proteins relate to their function and mode of regulation. Our structural studies also involve protein crystallography which is carried out as a collaborative effort.

Last modified: January 24, 2011 (ost)