Polysaccharide conformations measured by solution state x-ray scattering

Polysaccharides are semi-flexible polymers composed of sugar residues with a myriad of important functions including structural support, energy storage and immunogenicity. The local conformation of such chains is a crucial factor governing their interactions, where the relative orientation of adjacent sugar rings determines the propensity for hydrogen bonding and specific ion-mediated interactions with neighbouring chains. Traditionally this conformation has only been directly accessible in the solid-state, using crystallographic techniques such as fibre diffraction. Herein it is demonstrated that improvements in the quality of synchrotron-based x-ray scattering data means that conformation-dependent features, the positions of which are related to the linear repeating distance between single saccharide monomers, can now be measured in solution. This technique is expected to be universally applicable for polysaccharides that consist of comparatively stiff glycosidic linkages, and to have extensive relevance for a number of biological macromolecules, including glycosylated proteins.