title: Structure and Stability of Carbohydrate-Lipid Interactions. Methylmannose Polysaccharide-Fatty Acid Complexes.
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 (1) H 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.
authors.affiliation: Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
authors.forename: Lan
authors.initials: L
authors.lastname: Liu
authors.affiliation: Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
authors.forename: Iwona
authors.initials: I
authors.lastname: Siuda
authors.affiliation: Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
authors.forename: Michele R
authors.initials: MR
authors.lastname: Richards
authors.affiliation: Chemistry Department, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Justin
authors.initials: J
authors.lastname: Renaud
authors.affiliation: Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
authors.forename: Elena N
authors.initials: EN
authors.lastname: Kitova
authors.affiliation: Chemistry Department, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Mayer
authors.affiliation: Centre for Molecular Simulation, Department of Biological Sciences, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.
authors.forename: D Peter
authors.initials: DP
authors.lastname: Tieleman
authors.affiliation: Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada.
authors.forename: Todd L
authors.initials: TL
authors.lastname: Lowary
authors.affiliation: Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton, Alberta, T6G 2G2, Canada. john.klassen@ualberta.ca.
authors.forename: John S
authors.initials: JS
authors.lastname: Klassen
mesh_terms: D005227:Fatty Acids / Q000737:chemistry*; D008766:Methylmannosides / Q000737:chemistry*; D015394:Molecular Structure; D011134:Polysaccharides / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D008766:Methylmannosides; D011134:Polysaccharides; C008466:methylmannoside
keywords: NMR spectroscopy; carbohydrates; lipids; mass spectrometry; molecular dynamics