Jan F. Chlebowski, Ph.D.Professor of Biochemistry & Molecular Biology
PO Box 980614
Richmond, VA 23298-0614
Ph.D., Case Western Reserve University, 1969
- Research Associate, University College London, 1971
- Research Fellow, Yale University, 1976
Research interests are focused on assessing the mechanisms that modulate protein structure, control protein expression, and regulate enzymatic activity in vitro and in vivo. Our investigations center on the E. Coli alkaline phosphatase. A wide variety of methods are employed in our investigations including biophysical approaches (e.g. nuclear magnetic resonance, electron microscopy, Fourier-Transform infrared, circular dichroism, X-ray crystallography), traditional methods of protein chemistry and enzymology, as well as the application of molecular biology techniques.
The dimeric Zn(II) metalloenzyme alkaline phosphatase is found in the periplasmic space of the gram-negative E. Coli bacterium. The elements of the biosynthestic pathway leading to the information and localization of the mature protein provide an accessible model system representative of the complex pathway of protein maturation found in all organism. These include the mechanisms of transcriptional and translational control, transmembrane vectorial transport, the proteolytic event(s) which occur after compartmentalization to render this process irreversible, folding of the polypeptide chain, the binding of prosthetic groups, subunit assembly, and additional modification steps. Our most recent investigations have led to the discovery of an adenylated peptide, which is bound to the freshly isolated protein. Association of this compound induces structural alterations in the enzyme. Investigations of a broad regulatory function for this unusual peptide are in progress.
Deletions of segments of the amino terminal portion of the mature protein by either limited proteolysis or deletion mutagenesis subtly alter the structural and functional properties of alkaline phosphatase. Complete characterization of these truncated forms of the enzyme provides insight into factors important in influencing protein folding, subunit association, and allosteric effects. Solution of the crystal structure of the enzyme from which the amino terminal decapeptide has been deleted from both subunits in currently underway.