Our research is focused on using organic synthesis and enzymes coupled to state-of-the-art biophysical techniques such as fluorescence, NMR, mass spectrometry, and mass cytometry to creatively assemble new tools for studying biology.
1) Biofilm formation and modulation
Biofilms account for over 80% of human bacterial infections. Until recently the molecular details of biofilm formation have been limited. We are engaged in the study of key enzymes in the biofilm forming process. These studies involve the synthesis of oligosaccharide substrates of the enzymes crucial to biofilm formation. These compounds allow a detailed kinetic analysis of the enzymes mechanism and the development of inhibitors to biofilm formation. In the future we aim to develop a new class of antibiotics which target biofilm formation.
2) Development of probes for mass cytometry
The invention of mass cytometry (MC) by the Canadian company DVS Sciences (now Fluidigm) has transformative potential in the areas of cell-based research and clinical assays. MC overcomes many of the difficulties with flow cytometry, allowing for quantitative, highly multiplexed cytometric assays to be carried out using reagents tagged with heavy isotopes (Da >~100). These MC experiments have revealed novel cellular maturation pathways and interesting drug response profiles using antibodies tagged with Ln3+ isotopes. The new MC probes we are developing will enable unprecedented biochemistry to explore the dynamics of cellular metabolism in vivo that, in the long term, will inform disease treatments.
3) Protecting group-free carbohydrate synthesis
Synthetic carbohydrate chemistry is plagued by lengthy sequences dominated by non-productive protecting-group exchanges. A focus of the Nitz group is the development of protecting-group-free glycosidation protocols, enabling rapid and green access to carbohydrate-based compounds of biochemical and industrial interest.
4) Cyclodextrin functionalization and supramolecular sensor design
Selectively functionalized β-cyclodextrins (β-CDs) have a wide range of applications including molecular recognition, drug delivery and polymer assembly, but are difficult to access through existing methodology. We have developed a highly-selective, high-yielding, guest mediated-covalent capture approach to mono-functionalize heptakis-[6-deoxy-6-(2-aminoethylsulfanyl)]-β-CD (1). We are currently focused on the methodology development for the synthesis of complex heterofunctionalized β-CDs and sensor design.
5) Development of peptide substrates for C. difficile Toxin B
C. difficile is the major cause of antibiotic-associated diarrhea and pseudomembranous colitis. The potent cytotoxicity of its two virulence factors, Toxin A and Toxin B, results from the toxins’ ability to inactivate small GTPases in the cytosol by transferring a glucose moiety to the threonine residue at active sites. In this project, we are developing novel peptide substrates for the glucosyltransferase domains of Toxin B. These peptides are expected to be used as inhibitors of Toxin B or novel protein tags that could be grafted onto a protein of interest.