Comparison of the conformation of the epitope of alpha(2-->8) polysialic acid with its reduced and N-acyl derivatives: Biochemistry

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TypeArticle
Journal titleBiochemistry
Volume32
Issue15
Pages40074013; # of pages: 7
SubjectACID; Acids; analysis; bacterial; binding; CALCULATION; CALCULATIONS; Canada; Carbohydrate Conformation; Carbohydrate Sequence; chemistry; Comparative Study; conformation; ENERGY; energy calculations; epitope; Epitopes; Escherichia coli; helix; immunology; Magnetic Resonance Spectroscopy; Methods; Models,Molecular; Molecular Sequence Data; NMR; Oxidation-Reduction; PARAMETERS; POLYSACCHARIDE; Polysaccharides; Polysaccharides,Bacterial; POTENTIAL; SIALIC; Sialic Acids; SIALIC-ACID; SPECTROSCOPIC; stability; SUBSTITUENT
AbstractThe immunological properties of alpha(2-->8) polysialic acid have been rationalized in terms of the presence of an epitope situated on a unique extended helical segment (n approximately 9) of the polymer. The critical importance of the carboxylate group to the stability of the extended helical epitope can be ascertained from NMR spectrocopic studies and potential energy calculations on the carboxyl reduced alpha(2-->8) polysialic acid. These studies indicate that the extended helix (n approximately 9) is not stabilized in the reduced polymer and that the majority of conformers can only have helical parameters with n = 2 and 3. This result is also consistent with the fact that the reduced alpha(2-->8) polysialic acid, contrary to its acidic counterpart, exhibits conventional immunological properties. Only five to six reduced oligomers are required to inhibit the binding of the reduced polysialic acid to its homologous antiserum. NMR spectroscopic analysis and potential energy calculations on the N-propionyl, N-butanoyl, N-isobutanoyl, N-pentanoyl, N-hexanoyl, and N-glycolyl derivatives of alpha(2-->8) polysialic acid indicate that, despite the bulk of some of these substituents, they did not disrupt the extended helical conformer. The presence of the extended helical epitope in some of these N-acyl derivatives has also been confirmed from immunological data
Publication date
LanguageEnglish
AffiliationNational Research Council Canada; NRC Institute for Biological Sciences
Peer reviewedNo
NRC numberBAUMANN1993
NPARC number9384560
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Record identifier6ff09053-81f4-4152-b7e1-2c4a6363e096
Record created2009-07-10
Record modified2016-05-09
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