Technical basis for nuclear magnetic resonance approach for glycoproteins

Abstract

Glycophobia in structural biology is strongly associated with the unpredictable, heterogeneous nature of protein glycosylation and the complex, flexible structures of the glycoprotein glycans. Moreover, glycoproteins cannot be produced by conventional bacterial expression systems. Nuclear magnetic resonance (NMR) spectroscopy assisted by other analytical and preparative techniques can now successfully address these issues. Recombinant glycoproteins can be expressed with stable isotope labeling using a variety of eukaryotic production vehicles. Glycoforms of glycoproteins can be remodeled by genetic engineering of the production vehicles as well as in vitro enzymatic reactions. Stable-isotope-assisted NMR techniques have provided detailed information regarding conformational dynamics and interactions of the carbohydrate chains in solution, giving insights into the functional mechanisms of glycoprotein glycans.