NMR Identification of Substructural Glucose Units in the Amylopectin Superstructure: The example of Rhodella Violacea Amylopectin

International audienceIn the course of a study on Rhodella Violacea (Rhodophyta) starch was isolated as the reserve polysaccharide. The two fractions amylose and amylopectin were separated and each fraction was analysed by multidimensional high field NMR spectroscopy. Several glucose residues occupying segregate positions in the amylopectin macromolecules displayed different resonance frequencies. The structural characterisation -proton spin-systems and carbon resonance frequencies- of these atypical glucose sub-units was undertaken. The results of these analysis are presented. The purified amylopectin fraction from the reserve polysaccharide accumulated by the red algae Rhodella Violacea (Rhodophyta) was isolated and analysed by NMR. Eight different anhydro-glucose residues occupying various positions in the polysaccharide and having different resonancefrequencies were identified using a series of multi-dimensional homo and heteronuclear NMR experiments