The information that regulates the way in which cells recognize and respond to their neighbors resides at the area of contact between cells, in particular, in the molecular structures present at the cell surface. Complex carbohydrates are major components of the cell surface and are found conjugated as glycoproteins and glycolipids. Oligosaccharides differ in structure between cells, are involved in intercellular recognition processes during development, and are known to be modified in metastatic cancer cells. My laboratory focuses on an understanding of the enzymes that synthesize cell surface carbohydrates, the glycosyltransferases. In addition, characterization of the carbohydrate structures themselves and development of new methods for elucidation of these molecules is ongoing.
This includes new methods in higher-dimensional nuclear magnetic resonance (NMR) spectroscopy and fundamental studies in fragmentation of carbohydrate molecules by mass spectrometry, with the overall goal being to assign the detailed structures of these complex molecules unambiguously.
The glycosyltransferases in mammals are a large family of enzymes (over 100) localized primarily to the Golgi apparatus, which transfer in assembly-line fashion a series of monosaccharides to a growing oligosaccharide chain. My laboratory is interested in a series of glycosyltransferases involved in synthesis and branching of novel core structures of glycoprotein oligosaccharides, and in coming to understand the control of expression and role of these enzymes in different tissues.
For structural elucidation of glycoprotein oligosaccharides, we employ high-field NMR, mass spectrometry, and gas chromatography-mass spectrometry, in addition to specific methods of chemical degradation which are topics of research in the lab. Recent work has dealt with developments of gas-phase methods for separation and differentiation of oligosaccharide isomers.