Abstract: Complex carbohydrates play crucial roles in energy storage, cell recognition and structural building. Their functional structure is often elusive due to the technical difficulty in characterizing these molecules, which are typically polymorphic and disordered in structure. We will summarize our recent progress in developing 2D/3D 13C-13C/15N correlation solid-state NMR to investigate the functional structure and macromolecular assembly of complex carbohydrates, proteins and lignin in two carbohydrate-rich biosystems: the disease-relevant, pathogenic fungi and the energy-rich plant biomass. The carbohydrate armor (cell walls) of pathogenic fungi are found to contain a hydrophobic scaffold of chitin and α-1,3-glucan, which is surrounded by a hydrated matrix of diversely linked β-glucans and capped by a dynamic, outer layer rich in glycoproteins . Built upon this structural frame, we are currently identifying the structural factors that contribute to drug resistance and fungal virulence. In addition, the resolution improvement from the world-record 1.5 GHz (35 Tesla) NMR magnet at National High Magnetic Field Laboratory allows us to fully resolve the highly polymorphic conformations of these biomolecules in intact and living fungal cells. In plant biomass, the two hydrophobic domains of lignin and cellulose are found to be bridged by the hemicellulose xylan in a conformation-dependent manner and via electrostatic interactions . These findings provide molecular guide on the development of novel antifungal medications and better bioenergy crops. The implementation of a carbohydrate NMR database and the development of methods for skip isotope-labeling and enabling statistical analysis of unlabeled biomolecules will also be briefly discussed.
This event was published on January 31, 2020.