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Structure and Stability of Carbohydrate–Lipid Interactions. Methylmannose Polysaccharide–Fatty Acid Complexes |
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| Authors: | Dr. Lan Liu Dr. Iwona Siuda Dr. Michele R. Richards Dr. Justin Renaud Dr. Elena N. Kitova Prof. Paul M. Mayer Prof. D. Peter Tieleman Prof. Todd L. Lowary Prof. John S. Klassen |
| Affiliation: | 1. Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada;2. Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada;3. Chemistry Department, University of Ottawa, Ottawa, Ontario, Canada |
| Abstract: | We report a detailed study of the structure and stability of carbohydrate–lipid interactions. Complexes of a methylmannose polysaccharide (MMP) derivative and fatty acids (FAs) served as model systems. The dependence of solution affinities and gas‐phase dissociation activation energies (Ea) on FA length indicates a dominant role of carbohydrate–lipid interactions in stabilizing (MMP+FA) complexes. Solution 1H NMR results reveal weak interactions between MMP methyl groups and FA acyl chain; MD simulations suggest the complexes are disordered. The contribution of FA methylene groups to the Ea is similar to that of heats of transfer of n‐alkanes from the gas phase to polar solvents, thus suggesting that MMP binds lipids through dipole‐induced dipole interactions. The MD results point to hydrophobic interactions and H‐bonds with the FA carboxyl group. Comparison of collision cross sections of deprotonated (MMP+FA) ions with MD structures suggests that the gaseous complexes are disordered. |
| Keywords: | carbohydrates lipids mass spectrometry molecular dynamics NMR spectroscopy |