Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Neisseria meningitidis [ICD11:
XN1DV 
];
infection due to Escherichia coli [ICD11:
XN6P4 ]
The structure was elucidated in this paperNCBI PubMed ID: 12617660Journal NLM ID: 7503056Publisher: American Chemical Society
Institutions: Edgewood Chemical - Biological Forensic Analytical Center, Battelle Memorial Institute Edgewood Operations, 1204 Technology DriVe, Aberdeen, Maryland 21001, the Laboratory of Biophysics, Center for Biologics EValuation and Research, Food and Drug Administration, 1401 RockVille Pike, RockVille, Maryland 20852
To elucidate the role of secondary structure in the immune response against α(2→8)-linked polysialic acid, the capsular polysaccharide of Group B meningococci, we have investigated its solution dynamics by using specific models of molecular motion and hydrodynamic modeling to interpret experimental NMR data. (13)C-{(1)H} NMR relaxation times and steady-state NOE enhancements were measured for two aqueous solutions of α(2→8)-linked sialic acid polysaccharides. Each contained a unique distribution of polysaccharide chain lengths, with average lengths estimated at 40 or 400 residues. Models for rigid molecule tumbling, including two based on helical conformations proposed for the polysaccharide,(31) could not explain the NMR measurements. In general for these helices, the correlation times for their overall tumbling that best account for the NMR data correspond to polysaccharide chains between 9 and 18 residues in length, far short of the average lengths estimated for either solution. The effects of internal motions incorporated into these helices was modeled with an effective correlation time representing helix tumbling as well as internal motion. This modeling demonstrated that even with extreme amounts of internal motion, "flexible helices" of 25 residues or more still could not produce the NMR measurements. All data are consistent with internal and segmental motions dominating the nuclear magnetic relaxation of the polysaccharide and not molecular tumbling. Statistical distributions of correlation times have been found specifically for the pyranose rings, linkage groups, and methoxy groups that can account for the measured relaxation times and NOE enhancements. The distributions suggest that considerable flexibility attends the polysaccharide in solution, and the ranges of motional frequencies for the linkage groups and pyranose rings are comparable. We conclude that the Group B meningococcal polysaccharide is a random coil chain in solution, and therefore, does not have antigenic epitopes dependent upon a rigid, ordered conformation.
NMR, conformation, correlation, meningococcal, meningococci, capsular, polysaccharide, group, molecular, molecule, capsular polysaccharide, conformational, dynamics, polysaccharides, sialic acid, aqueous, solution, NOE, relaxation, polysialic acid, distribution, model, models, motion, modeling, enhancement, flexibility, helical, solutions
Structure type: homopolymer
Location inside paper: Fig. 1
Trivial name: colominic acid sodium salt, colominic acid, type B polysaccharide, polysialic acid, PSA, oligosaccharide repeating unit, α-2,8-linked polysialic acid
Compound class: CPS, O-polysaccharide, K-antigen, O-antigen
Contained glycoepitopes: IEDB_136794,IEDB_141115,IEDB_142352,IEDB_146100,IEDB_149174,IEDB_150072,IEDB_150937,IEDB_153199,IEDB_226810,IEDB_558870,IEDB_983929,SB_170,SB_171,SB_172,SB_35,SB_42,SB_84
Methods: NMR, molecular modeling
3D data: conformation data
NCBI Taxonomy refs (TaxIDs): 491,
1392869Reference(s) to other database(s): GTC:G30588ZL, GlycomeDB:
677
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
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