Professor of Biochemistry and Molecular Biology
B.A., Ph.D. (1963) Johns Hopkins University

E-mail: brewer@bmb.uga.edu

Office: A314B Life Sciences
Phone: 542-1773
Lab: A316 Life Sciences
Lab Phone: 542-1776

I am interested in protein structure and how it is related to protein function. The general experimental approaches employed are protein chemistry, enzymology and physical techniques, such as calorimetric and differential scanning calorimetric analyses, sedimentation velocity and equilibrium studies, stopped-flow measurements, fluorescence lifetime determinations and conventional spectroscopic experiments.

Most of my work currently is on yeast enolase. I am particularly interested in its mechanism of action and in the relation of enzyme activity to its subunit association (the enzyme is a dimer). I have been collaborating with a protein crystallographer at the University of South Carolina, Dr. Lukasz Lebioda, preparing yeast enolase mutants using site-directed mutagenesis techniques. I have prepared eight mutants and am preparing four more. The residues altered intially are those that interact directly with the substrate. Once prepared, physical and enzymatic analyses are carried out to test various proposed mechanisms of action, then the mutant enolases are sent to Dr. Lebioda for determination of the structure of their complexes with substrate. Although a simple-appearing mechanism, it involves removal of a very non-acidic hydrogen from carbon-2 of the substrate and hydroxyl, a poor leaving group, from carbon-3. This is effected through interaction with an arginyl, two lysyl, two histidyl, two glutanyl, a seryl and two metal ions.

The subunits appear to interact in an anticooperative fashion with a movable loop of each subunit interacting so that only one is near its substrate at a time. Mutations of the residue(s) forming a hydrogen-bonded link between subunits which keeps both loops from coming near the bound substrate molecules at the same time are under way.

Full Publications: 76

Selected recent publications:

• Lebioda, L. and Brewer, J.M. Current perspectives on the mechanism of catalysis by the enzyme enolase. In Advances in Biophysical Chemistry (C.A. Bush, Ed.), vol. 6, JAI Press, Greenwich, Conn., in press.
  
  
• Sangadala, V.S., Glover, C.V.C., Robson, R.L., Holland, M.J., Lebioda, L. and Brewer, J.M. Preparation by site-directed mutagenesis and characterization of the E211Q mutant of yeast enolase 1. Biochim. Biophys. Acta (1995) 1251:23-31.
  
  
• Zhang, E., Hatada, M., Brewer, J.M. and Lebioda, L. Catalytic metal ion binding in enolase: the crystal structure of enolase-Mn2+-Phosphonoacetohydroxamate complex at 2.4 Å resolution. Biochemistry (1994) 33:6295-6300.
  
  
• Brewer, J.M., Robson, R.L., Glover, C.V.C., Holland, M.J. and Lebioda, L. Preparation and characterization of the E168Q site-directed mutant of yeast enolase 1. Protein: Structure, Function and Genetics (1993) 17:426-434.
  
  
• Hilal, S.H., Brewer, J.M., Lebioda, L. and Carreira, L.A. Calculated effects of the chemical environment of 2-phospho-D-glycerate on the pKa of its carbon-2 and correlations with the proposed mechanism of action of enolase. Biochem. Biophys. Res. Comm. (1995) 211:607-613.
  
  
• Wang, S., Scott, R.A., Lebioda, L., Zhou, Z.H. and Brewer, J.M. An x-ray absorption spectroscopy study of the interactions of Ni2+ with yeast enolase. J. Inorg. Biochem. (1995) 58:209-221.