SOLID-STATE C-13 NMR INVESTIGATIONS OF THE GLYCOSIDIC LINKAGE IN ALPHA-ALPHA' TREHALOSE

The sugar trehalose is known to play a central role in the desiccation tolerance of many organisms. Essential to trehalose's role are its gl ass forming abilities and ability to directly interact with lipid mole cules. Detailed information on the structure and dynamics of glassy tr ehalose and its interactions with lipids, however, have been elusive. We have used solid-state NMR and ab initio quantum mechanical methods (Gaussian 94) in order to characterize the possible molecular conforma tions of trehalose. Using a simplified structure (2-(tetrahydropyran-2 -yloxy) tetrahydropyran) as a model we have calculated the energy and C-13 magnetic shielding parameters as a function of the two glycosidic torsion angles. Combining ab initio derived maps and using the C-13 l ineshape as constraints we were able to construct the torsion angle di stribution map for alpha-alpha' trehalose. We believe measurements of C-13 isotropic chemical shift and other solid-state NMR tensor paramet er distributions in combination with ab initio methods can prove usefu l in identifying sources of structural disorder in glassy trehalose. B y monitoring these structural distributions new information about the membrane surface associative properties of trehalose and other sugars should be accessible. (C) 1998 Elsevier Science B.V. All rights reserv ed.