PubMed · 7326362
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
W T Winter, I Adelsky. 1981. Pneumococcal polysaccharide conformations.. https://doi.org/10.1002/bip.1981.360201214
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Circular birefringence (CB, or optical rotation) and linear birefringence (LB) were measured for gellan gum aqueous solutions with and without salt to examine the gelling system in the helical structure as well as in the orientation. It was found that gelling samples with salt show nonzero LB values, whereas LB is zero for the samples without salt even in the gel state. This difference can be explained by the thermal deformation of the system containing anisotropic aggregations of helices formed with the shielding effect of the added salt on the intramolecular and intermolecular electrostatic repulsions. Considering that the presence of LB in the system affects the estimation of CB, we developed an original procedure of the CB measurement to eliminate the contribution of LB. It was shown that our methods for eliminating the contribution of LB can improve the CB measurement for the gellan gum gel. The temperature dependence of [alpha] for the samples with salt in the gel state is quite different from that for the samples without salt, suggesting that the aggregates of helices in the samples containing a high concentration of salt form a supramolecular structure that contributes to CB.
A natural polysaccharide schizophyllan (SPG) has been known to form a stable complex with poly(dA). We attached a poly(dA)(80) tail to the both ends of a linear double-stranded DNA, which had been prepared from a plasmid DNA vector. The poly(dA) tailed DNA verified to form complex with SPG by gel electrophoresis and atomic force microscopy (AFM). AFM images indicated that the complexes exhibit a dumbbell-like architecture, that is, quite similar to that of adenovirus genome. The complex demonstrated excellent exonuclease resistance, probably because of the protection effect by SPG complexation.
A novel approach to the synthesis of beta-glycosides of N-acetyl-D-glucosaminuronic acid, in six steps and good overall yield from N-acetyl-d-glucosamine, has been developed. The key synthetic step was the Lewis acid mediated O-glycosidation of methyl 1,3,4-tri-O-pivaloyl-N-acetyl-D-glucosaminuronate (11). Elaboration of glucosaminuronides 15 and 18 provided novel sialylmimetics 21 and 22, which showed inhibition of Vibrio cholerae sialidase.