Anion specific conformational change in aqueous gellan gum solutions.

I NMR is applied to investigate the motional state and the selective interaction of I ions in tetramethylammonium form of gellan gum (TMA gellan), together with monitoring the conformational change by the optical rotation measurement. The experimental results indicate that I ion promotes the conformational transition, and there exists the preferential affinity of I ion for the ordered conformation of TMA gellan.