  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.
