Pyruvate carboxylase is a key metabolic enzyme that is a member of the family of biotin-dependent enzymes. The enzyme is regulated allosterically, primarily by acetyl CoA. Allosteric regulation of many enzymes is a common, but often poorly defined phenomenon, however, there is growing interest in the design of drugs that allosterically modulate the activity of enzymes. This project will characterize how acetyl CoA regulates and coordinates the control of protein structure and its dynamics and will provide a model for understanding similar complex enzymes.
The project uses kinetics and biophysical methods to examine the relationships between the structure of pyruvate carboxylase and its catalytic mechanism and then how the allosteric activator acetyl CoA binds to the enzyme to alter its structure and dynamics to impose regulatory control on the activity of the enzyme. Thus, the project combines the techniques of X-ray crystallography, protein engineering, rapid-reaction methods and thermodynamic analysis to understand how the enzyme functions as a tetramer and how there is allosteric cross-talk between the subunits, including regulation by acetyl CoA. This will provide the basis for the future design of allosteric modulators of pyruvate carboxylase that have therapeutic potential in the treatment of some serious infectious diseases and diabetes.
- Sarawut Jitrapakdee, Mahidol University
- Martin St. Maurice, Marquette University
- Tonya Zezycki, University of East Carolina