Organic Chemistry Division

Laboratory for Natural Product Chemistry

Research Interests

1. Chemistry and function of immunostimulating glycoconjugates from bacterial cell surfaces.
2. Efficient and selective methods for glycosylation and oligosaccharide synthesis.
3. New labeling and conjugation methods for biomolecules.
4. Positron emission tomography (PET) imaging of oligosaccharides and proteins for new functional studies.

We have studied the chemistry and biology of cell surface glycoconjugates from bacteria and mammals. Synthetic studies of bacterial immunostimulating glycoconjugates, such as lipopolysaccharide (LPS) and peptidoglycan, led to the identification of the active components responsible for switching on the primary defense mechanism against bacterial infection in host animals. Innate immunity sensing receptors have been identified, and the receptor?ligand interactions have been elucidated using our synthetic compounds. Stereoselective glycosylation reactions, such as α-sialylation and β-mannosylation, were established in this laboratory. The efficient synthesis of complex oligosaccharides using solid-phase methods is currently being pursued. New amino group labeling methods, via rapid 6π-azaelectrocyclization, were developed for radiolabeling, fluorescence labeling, and bioconjugation. These methods are currently being applied to proteins and oligosaccharides to enable PET imaging.