Solution Conformation and Dynamics of the O-Antigen of the Major Lipopolysaccharide from Sinorhizobium fredii SMH12

The conformational and dynamic behavior of the O-antigen of the lipopolysaccharide of Sinorhizobium fredii SMH12, a wide-range host bacterium isolated from nodulated soybean plants growing in Vietnam, was studied. The O-antigenhas a repeating unit consisting of the trisaccharide 4)-α-D-GalpA-(13)-2-O-Ac-α-L-Rhap-(13)-2-O-Ac-α-D-Manp-(1, where the O-6 position of the mannose residue in the repeating unit is unsubstituted, acetylated, or methylated in an approximate ratio 1:1:2. For the analysis of the conformational and dynamic behavior, the deacetylated polysaccharide was employed. A combination of NMR spectroscopic methods assisted by molecular mechanics and dynamic simulations was employed to deduce its major conformational and dynamic features. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)