A high-resolution solid-state 13C NMR study of the secondary structure of branched (1.RAR.3)-.BETA.-D-glucans from fungi: Evidence of two kinds of conformers, curdlan-type single-helix and laminaran-type triple-helix forms, as manifested from the conforma

概要

論文の詳細を見る
The high-resolution 13C NMR spectra of a variety of fungal branched (1→3)-β-D-glucans were recorded in a DMSO solution and a lyophilized solid in order to gain an insight into the primary and secondary structures in relation to their gel-forming property. We found that all the five lyophilized branched (1→3)-β-D-glucans examined so far, except lentinan, exhibit the laminaran-type triple-helix form, as established by the close resemblance of the 13C NMR spectra among them. On the contrary, lentinan taking the curdlan-type singlehelix conformation was readily converted to the triple-helix form by lyophilization after having been dissolved in a 8M urea solution (1M=1 mol dm−3) and dialysis against distilled water. This finding should be compared with the similar conformational change of curdlan: the conversion by this procedure was at most 50%; annealing at 150°C, followed by slow cooling, was essential for a complete conversion. This treatment did not induce the reverse conformational change from the triple helix to the single helix. The differential behavior of gelformation between the linear and branched (1→3)-β-D-glucans was explained in terms of the molecular conformations in the solid and gel states.
公益社団法人日本化学会の論文