Protein Structure and Function/X-ray Crystallography/Membrane Proteins

My lab uses X-ray crystallography, molecular biology, computer-based protein structure analysis, biochemical characterization, and other techniques to determine the three-dimensional structures and molecular mechanisms of transmembrane proteins and sugar isomerases. Several of the proteins currently being studied play important roles in antibiotic resistance, cancer, and nonspherocytic hemolytic anemia.

Transmembrane signaling, ion transport, cell-cell communication, maintenance of cell structure, and other vital cell activities involve proteins that are embedded in the cell membrane. Analyses of DNA sequences from organisms for which complete genomes are available suggest that transmembrane proteins make up more than 25% of the proteins in a cell. However, much less is known about the structure and function of transmembrane proteins than for soluble proteins. We are currently working on expressing and purifying several transmembrane transporters for biochemical and structural analysis.

Another focus of my lab is a multifunctional protein called phosphoglucose isomerase/neuroleukin/autocrine motility factor (PGI/NL/AMF). This protein has very different roles inside and outside the cell. Inside the cell it serves as an enzyme in glycolysis, and outside the cell it serves as a growth factor. It causes some leukemia cells to differentiate, and it causes an increase in the motility of other cancer cells, so an understanding of its extracellular roles may lead to better cancer treatments. We determined the X-ray crystal structure of PGI/NL/AMF during my postdoctoral research. To learn more about the mechanism of catalysis, my lab at UIC has grown crystals of the protein with several inhibitor molecules bound in the active site. These inhibitors were chosen to mimic different steps in the isomerase reaction. A comparison of multiple structures of the protein with these bound inhibitors is helping us learn how amino acid residues in the enzyme active site interact with the substrate to promote catalysis.

Representative Publications

Jeffery, C. J. (2009) Moonlighting Proteins - An Update. Molecular Biosystems. 5:345-50.

Arsenieva, D., B. L. Appavu, G. Mazock, and C. J. Jeffery. (2009) X-ray Crystal Structure of Trypanosoma brucei Phosphoglucose Isomerase Complexed with Glucose-6-phosphate at 1.6 Å Resolution. Proteins: Structure, Function, and Bioinformatics 74:72-80.

Lee, J.H. and C. J. Jeffery. (2005) The Crystal Structure of Rabbit Phosphoglucose Isomerase Complexed with D-Sorbitol-6-phosphate, an Analog of the Open Chain Form of D-glucose-6-phosphate. Protein Science. 14:727-34.

Roux, C., J. H. Lee, C. J. Jeffery, and L. Salmon. (2004) Inhibition of type I and type II Phosphomannose Isomerases by the Reaction Intermediate Analogue 5 phospho-D-arabinonohydroxamic Acid Supports a Catalytic Role for the Metal Cofactor. Biochemistry. 43: 2926-34.

Arsenieva, D. and C. J. Jeffery. (2002) Conformational Changes in Phosphoglucose Isomerase Induced by Ligand Binding. Journal of Molecular Biology. 323: 77-84.

Arsenieva, D., R. Hardré, L. Salmon, and C. J. Jeffery. (2002) The Crystal Structure of Rabbit Phosphoglucose Isomerase Complexed with 5-phospho-D-arabinonhydroxamate. Proc. Nat. Acad. Sci., USA. 99:5872-7.

Jeffery, C. J. Moonlighting Proteins. (1999) Trends in Biochemical Sciences. 24: 8-11.