This project entails structure and dynamics studies of biological macromolecules through the use of nuclear magnetic resonance (NMR) spectroscopy. The present foci are polysaccharides, important vaccine components whose structure is poorly understood. This project entails structure and dynamics studies of biological macromolecules through the use of nuclear magnetic resonance (NMR) spectroscopy. The present foci are polysaccharides, important vaccine components whose three-dimensional structure is poorly understood. I am using NMR to detect changes in the spectra of carbohydrates such as sucrose, cellobiose, maltose and lactose. These simple disaccharides will serve as models to provide the basis for structural studies of oligo- and polysaccharides. Building on results obtained last year, I developed a new method for determine the pucker of the fructofuranosyl ring in sucrose. This was accomplished by measuring a combination of one-bond, and long range 1H-13C residual dipolar couplings (RDCs), and 1H-1H RDCs (at 800 MHz). The RDCs were then fit to 20 structures and the goodness of fit was evaluated. Best fits for this pucker were found to be in the NW quadrant of the pseudorotational wheel, in agreement with previous experiments. My results also indicate that there is motion in this ring, which facilitates the pseudorotation. A paper reporting these results was submitted to JACS. The three-dimensional solution structures of sucrose, lactose and cellobiose are currently being studied using RDCs, with the above methodology now tested.
