Studies on the conformational aspects of inulin oligomers.

The conformational studies of inulin oligomers from G-F2 to G-F9, which isolated from Platycodon grandiflorum, suggested a plausible conformational change between G-F7 and G-F8 from the trends in their chemical shift patterns and molecular rotation; the oligomers higher than G-F8 would form some secondary conformations more rigid than shorter oligomers. On the other hand, spin-lattice relaxation (T1) studies of the protons proposed through-space interactions of 2- and 4-H's of glucose moiety in G-F5, presumably with some atom(s) of the terminal fructose moiety. This would reflect that the inulin molecule adopts a 5/1 helix.