A high-resolution solid-state 13C NMR study of (1.RAR.3)-.BETA.-D-glucans from various sources. Conformational characterization as viewed from the conformation-dependent 13C chemical shifts and its consequence to gelation property.

概要

論文の詳細を見る
High-resolution solid-state 13C NMR spectra of a variety of (1→3)-β-D-glucans in the solid state were recorded by means of cross polarization-magic angle spinning (CP–MAS) NMR spectroscopy. We found that the C-1 and C-3 peak-positions of these glucans are significantly displaced (up to 8 ppm) depending upon variety of samples used. Interestingly, these glucans obtained by lyophilization or spray-drying possess regular secondary structures as detected by displacements of the conformation-dependent 13C chemical shifts. In fact, at least four kinds of molecular conformations were distinguishable by 13C NMR spectroscopy. Gel-forming ability of linear (1→3)-β-D-glucans, however, was related to the presence of a single particular conformation without involving any other form. By contrast, gel-formation was noted for a branched glucan whose conformation is similar to that of a linear glucan without gel-forming ability. Further, conformation of all these linear and branched (1→3)-β-D-glucans turned out to be the same when solid samples were prepared by lyophilization from DMSO solution.
公益社団法人日本化学会の論文