chapter  1
16 Pages

New Frontiers in Nuclear Magnetic Resonance Spectroscopy: Use of the Nano*NMR Probe for the Analysis of Microgram Quantities of Complex Carbohydrates

We describe here the use of a Nano«NMR probe for obtaining one-and two-dimensional1H nuclear magnetic resonance (NMR) spectra of complex oligosaccharides available in only very small quantities. These results were obtained on glycosaminoglycan (GAG)-type chains isolated from human melanoma cells in culture; however, because there are no intrinsic limita­ tions to the approach, it is applicable to any situation where an NMR analysis of a limited amount of a carbohydrate is required. The GAG-type oligosaccharides used in this study were obtained by adding /3-xylosides to the cell culture to prime GAG biosynthesis [1,2]. These acceptors diffuse into the Golgi apparatus, where they compete with endogenous core pro­ teins to make protein-free GAG chains. Freeze and coworkers [3] had characterized several of the GAG chains produced in this manner by human melanoma cells; however, about 10-15% of the anionic oligosaccharides proved to be resistant to the enzymatic digestions used to successfully ana­ lyze the majority of oligosaccharides. The use of NMR spectroscopy allowed us to explain the resistance of the minor oligosaccharides to enzy­ matic digestions and demonstrated the existence of a previously unidenti­ fied core-related structure.