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Jeff D. Cronk


Associate Professor, Chemistry and Biochemistry
Gonzaga University


General Chemistry - CHEM 101 Bioanalytical Chem - CHEM 240 All courses Home Publications Biographical information Other resources Contact me


My research interests center on structural enzymology. I would like to contribute to an understanding of how the catalytic prowress, exquisite specificity, and regulatory mechanisms of enzymes can be explained by recourse to detailed analysis of their molecular structures. The primary tools used to probe enzyme function in my laboratory are heterologous protein overexpression, protein purification, X-ray crystallography, enzymatic assay, and site-directed mutagenesis.

The principal project currently underway in the laboratory concerns a specific example of a type of enzyme, known as carbonic anhydrase, that is derived from the bacterium Escherichia coli. This enzyme, dubbed ECCA, has some unusual properties compared to other carbonic anhydrases. First, it is a member of the β (beta) class of carbonic anhydrases that shows an atypical zinc coodination pattern. Second, its activity is strongly pH-dependent, with the transition to low activity occurring at near physiological pH.

To further investigate these unusual properties, analysis of high-resolution X-ray crystallographic strucures is combined with site-directed mutagenesis. From this approach, a hypothesis that ECCA and certain other β class carbonic anhydrases are regulated by a confomational switch that alters the coordination around the catalytically essental zinc ion has emerged. With further study, we hope to probe the validity of this hypothesis.