Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
];
infection due to Neisseria meningitidis [ICD11:
XN1DV ]
NCBI PubMed ID: 22703338Publication DOI: 10.1021/ja300624jJournal NLM ID: 7503056Publisher: American Chemical Society
Correspondence: daron_freedberg
nih.gov
Institutions: Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 1401 Rockville Pike, Rockville, Maryland 20852-1448, United States
Characteristic H-bonding patterns define secondary structure in proteins and nucleic acids. We show that similar patterns apply for α2-8 sialic acid (SiA) in H(2)O and that H-bonds define its structure. A (15)N,(13)C α2-8 SiA tetramer, (SiA)(4), was used as a model system for the polymer. At 263 K, we detected intra-residue through-H-bond J couplings between (15)N and C8 for residues R-I-R-III of the tetramer, indicating H-bonds between the (15)N's and the O8's of these residues. Additional J couplings between the (15)N's and C2's of the adjacent residues confirm the putative H-bonds. NH groups showing this long-range correlation also experience slower (1)H/(2)H exchange. Additionally, detection of couplings between H7 and C2 for R-II and R-III implies that the conformations of the linkers between these residues are different than in the monomers. These structural elements are consistent with two left-handed helical models: 2 residues/turn (2(4) helix) and 4 residues/turn (1(4) helix). To discriminate between models, we resorted to (1)H,(1)H NOEs. The 2(4) helical model is in better agreement with the experimental data. We provide direct evidence of H-bonding for (SiA)(4) and show how H-bonds can be a determining factor for shaping its 3D structure.
conformation, structure, sialic acid, model
Structure type: homopolymer ; n=4
Location inside paper: p.10717, fig.1
Trivial name: polysialic acid
Compound class: CPS
Methods: 13C NMR, 1H NMR, MD simulations, 15N NMR, nOe
3D data: molecular modeling
NCBI Taxonomy refs (TaxIDs): 1392869,
491Reference(s) to other database(s): GTC:G89228EH
Show glycosyltransferases
There is only one chemically distinct structure:
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