The complexity of glycoprotein-derived glycans

A brief review is presented of our studies on the structure of glycoprotein-derived glycans. The emphasis is on the introduction of high-resolution ¹H-NMR spectroscopy for the unambiguous determination of primary structures. For this purpose, we developed the structural reporter group concept. Structural reporters are defined as unique markers of structural elements in the NMR spectra. Application of this concept led to the discovery of numerous new structures. Furthermore, a number of structures presented in the literature could be corrected. The results are relevant for insight in the various steps in glycan metabolism in health and disease, for the function and mode of action of glycans in vivo and for the interpretation of structural information obtained through other techniques. The strength of the approach is further shown for several highly complex glycoproteins, carrying very heterogeneous and complicated glycans.