Structural glycomics by NMR

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We have developed a systematic methods for structural glycomics by using nuclear magnetic resonance (NMR) spectroscopy. In this methodology, prior to NMR analyses, the covalent structures of target glycoproteins are determined on the basis of the multi-dimensional HPLC data, which now enable us to perform quantitative glycosylation profiling at molecular, cellular, and tissue levels dealing with sulfated and glucuronyl oligosaccharides. In addition, the library of the oligosaccharide standards constructed by the multi-dimensional HPLC can be a useful tool for comprehensive analyses of potential sugar-binding activities of proteins. We have successfully elucidated the molecular mechanisms of the glycoprotein-fate determination in cells through the interactions with a variety of intracellular lectins operating as molecular chaperones, cargo receptors, and ubiquitin ligases.To analyze structures, dynamics, and interactions of glycoconjugates at atomic level, we employed a 920 MHz ultra-high field NMR spectroscopy combined with stable isotope labeling techniques of sugar chains. By this approach, we have revealed glycoform-dependent conformational alteration of the Fe region of human immunoglobulin G1, which affects the effector functions of this glycoprotein. Our ultra-high field NMR study also revealed the interaction modes between amyloid β and ganglioside clusters, which are associated with the onset of Alzheimer's disease. These studies will offer a new opportunity for the rational design of therapeutic antibodies as well as drugs targeting sugar-protein interactions.