The Jeffery lab studies the molecular mechanisms of enzyme catalysis and transmembrane signalling and transport. We employ X-ray crystallography, molecular biology, computer-based structure analysis, and biochemical characterization of our target proteins. Our current projects include both transmembrane proteins and intracellular enzymes. Connie also coined the term "moonlighting proteins"

Transmembrane proteins. Analyses of complete genome sequences indicate that over 25% of an organism’s proteins are embedded in cellular membranes. Transmembrane proteins play vital roles in cell-cell communications, transmembrane signaling, ion transport and maintenance of cell structure and are the targets for the majority of pharmaceuticals in use today. In addition, the misfolding of specific transmembrane proteins can result in disease, such as in cystic fibrosis. In spite of the vast importance of transmembrane proteins, there are far fewer structures and molecular mechanisms known for transmembrane proteins than for soluble proteins. This difference is due to the presence of hydrophobic sequences that can make it difficult to express and isolate large amounts of these proteins and makes them refractory to many biochemical and structural methods. We are taking a two-pronged approach to improve our understanding of transmembrane proteins: structure/function studies of several specific proteins and a proteomics-level approach to improving methods for studying transmembrane proteins.

Structures and molecular mechanisms of PGI and other phosphosugar isomerases. Members of the Jeffery lab have solved five additional X-ray crystal structures of mammalian PGI and used them to develop a detailed model of its multistep catalytic mechanism. Ongoing projects include determining the X-ray crystal structures and mechanisms of two phosphosugar isomerase enzymes from the pathogens Pseudomonas aeruginosa and Trypanosoma brucei. P. aeruginosa causes chronic, serious lung infections in patients with cystic fibrosis (CF) that are a major cause of the decreased life span of CF patients. We are studying the bifunctional enzyme phosphomannose isomerase/GDP-D-mannose pyrophosphorylase, which is one of the proteins involved in the infection process. Another enzyme we are studying is from T. brucei, the causative agent in sleeping sickness. In the host's bloodstream, trypanosomes depend on the enzymes of glycolysis for energy production, so inhibitors of those enzymes would be good lead compounds for the design of therapeutics. It is hoped that novel inhibitors of the enzymes resulting from our research will serve as lead compounds for the future development of drugs to fight Pseudomonas and Trypanosoma infections.

Moonlighting proteins. Moonlighting proteins have multiple, seemingly unrelated functions not due to gene fusions or alternative splicing. Like PGI, which is a cytosolic enzyme and an extracellular cytokine, dozens of other proteins have been found to moonlight. Connie coined the term moonlighting proteins and has written several review articles that develop the idea of moonlighting proteins and describe additional moonlighting proteins from the literature, how they switch between functions, how they might have evolved, and how they might benefit the cell. She is currently writing two additional invited articles and planning computational studies of the sequences and structures of known moonlighting proteins.

Research Summaries: PGI Moonlighting Proteins Transmembrane Proteins

Lab Members

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Crystal Gallery

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Connie's CV

Lecture Notes for Bios454

***If you can’t grow bigger crystals, then grow bigger proteins!***

Prof. CONSTANCE JEFFERY