NMR Analysis of Bioprotective Sugars: Sucrose and Oligomeric (1→2)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranosides

Abstract

NMR spectroscopy yields structural information on a new class of bioprotectants with the general composition oligo(1 → 2)-α-d-glucopyranosyl-(1 → 2)-β-dfructofuranoside. Their smallest representative is sucrose for which conflicting models try to explain its cryoprotective properties. Starting from sucrose, we characterize the influence of the growing chain of oligo(1 → 2)-α-d-glucopyranoses. An analytical approach will be presented that can identify ultraweak membrane affinities, a property often discussed in the context of cryoprotectants. The most prominent feature of the vicinally connected (1 → 2)-α-d-glucopyranose oligomers is their well-defined solution structure with a stand-alone sugar helix. The unfolding barrier of this helix is large enough to become observable as line-broadening in the 1 H NMR.