Structural determination of the group K capsular polysaccharide of Neisseriameningitidis: a 2D-NMR analysis

1985 ◽  
Vol 63 (10) ◽  
pp. 2781-2786 ◽  
Author(s):  
Francis Michon ◽  
Jean Robert Brisson ◽  
René Roy ◽  
Harold J. Jennings ◽  
Fraser E. Ashton
Keyword(s):  
Capsular Polysaccharide ◽  
2D Nmr ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Electronic Effects ◽  
Nmr Studies ◽  
Polysaccharide Antigen ◽  
One Dimensional ◽  
The One

The capsular polysaccharide antigen of Neisseriameningitidis group K was isolated by Cetavlon precipitation and purified by ion-exchange chromatography. The structure of the K polysaccharide was determined to a large extent by comprehensive proton and carbon-13 nuclear magnetic resonance (nmr) studies. In these studies one-dimensional and two-dimensional experiments were carried out directly on the K polysaccharide. The K polysaccharide is composed of the following repeating unit: -4)β-D-ManpNAcA(1→3) [4-OAc]β-D-ManpNAcA(1→. Except for the one-bond couplings between their anomeric carbons and protons [Formula: see text], all the nmr spectroscopic evidence was consistent with both 2-acetamido-2-deoxy-D-mannopyranosyluronic acid residues adopting the 4C1 (D) conformation and having the β-D-configuration. This ambiguity in [Formula: see text] is probably due to through-space electronic effects generated by the presence of contiguous carboxylated sugar residues in the K polysaccharide. The O-acetyl substituents of the K polysaccharide are essential for its antigenicity to group K polysaccharide-specific antibodies.

scholarly journals 2618. Determination of the Chemical Structure of a Novel Pneumococcal Serotype, 39X

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S911-S911
Author(s):  
Feroze Ganaie ◽  
Jamil Saad ◽  
Lesley McGee ◽  
Andries van Tonder ◽  
Stephen Bentley ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Capsular Polysaccharide ◽  
Vaccine Development ◽  
Pcr Amplification ◽  
2D Nmr ◽  
Exchange Chromatography ◽  
Nmr Studies ◽  
Sequencing Project ◽  
Serotype Replacement ◽  
Pneumococcal Serotype

Abstract Background Streptococcus pneumoniae produces a diverse group of capsular polysaccharides (serotypes) that are important for the virulence of the organism and for the serotype-specific prevention of pneumococcal disease. As a consequence of widespread PCV usage and pneumococcal genome plasticity, the distribution of pneumococcal serotypes is changing with an increase in non-vaccine serotypes post-vaccine introduction, a phenomenon known as serotype replacement. Recently, a potentially novel serotype was described and was provisionally named as serotype 39X. Genetic studies suggest that this novel serotype may be a hybrid of serotypes 6C and 39/10A. Methods Three 39X strains with the distinct serological and genetic description of the cps biosynthetic loci were obtained from the Global Pneumococcal Sequencing project (www.pneumogen.net). Capsular polysaccharide from one (Camb.853/MNZ2334) of the 39X strains was purified by sequential ethanol precipitation followed by ion-exchange chromatography. To detect polysaccharide fractions during purification, an inhibition ELISA assay was developed using factor serum 10d. The chemical structure of the 39X repeating unit was determined using one-dimensional (1D) and 2D nuclear magnetic resonance (NMR). Results All three isolates were confirmed to have the 39X genotype by PCR amplification and sequencing of the 39X specific region (wciN6c-wcrO-wcrC39) of the cps locus. (Figure 1). The 39X capsule PS fractions were detected during purification and pooled for structural studies (Figure 2). 1D-NMR for 39X showed it to be chemically distinct (Figure 3). 2D-NMR studies revealed that five of the sugar residues in 39X PS are identical to those in 39 PS, except the acetylation (Figure 4). The remaining part of the structure is being investigated. Conclusion The 39X capsular PS has a distinct chemical structure in addition to its distinct serologic and genetic properties. Given that serotype 39X is a new serotype, it becomes the 100th pneumococcal serotype. The chemical structure supports the genetic depiction of serotype evolution as a result of recombination between well-characterized and unrelated serotypes. Structural elucidation of the 39X capsule PS will help facilitate our understanding of serotype replacement and vaccine development. Disclosures All authors: No reported disclosures.

Determination of homocysteine in plasma by ion-exchange chromatography

1989 ◽  
Vol 49 (5) ◽  
pp. 445-449 ◽  
Author(s):  
A. Andersson ◽  
L. Brattström ◽  
A. Isaksson ◽  
B. Israelsson ◽  
B. Hultberg
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Chromatography ◽  
Exchange Chromatography
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