Zou W, Li J, Vinogradov E, Cox A Removal of cell wall polysaccharide in pneumococcal capsular polysaccharides by selective degradation via deamination Carbohydrate Polymers218 (2019)
199-207
The structure was elucidated in this paper NCBI PubMed ID:31221321 Publication DOI:10.1016/j.carbpol.2019.03.070 Journal NLM ID:8307156 Publisher: Elsevier Correspondence: W. Zou <wei.zounrc-cnrc.gc.ca> Institutions: Human Health Therapeutic Research Center, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6, Canada
Pneumococcal cell wall polysaccharide (C-PS), a contaminant in pneumococcal capsular polysaccharide (Pn-PS) vaccines is degraded by mild deamination of the 4-amino-2-acetamido-2,4,6-tri-deoxy-galactose (AAT) in C-PS, which was carried out by addition of 5% aqueous sodium nitrite to a solution of polysaccharide in 5% aqueous acetic acid. Glycosidic linkage and functional groups such as O-acetates, phosphodiesters, and pyruvates were preserved under the conditions. The small fragments from degraded C-PS were removed by ultrafiltration or dialysis to provide essentially C-PS free Pn-PS. Because of the presence of AAT in its structure the deamination is not suitable for the purification of type 1 Pn-PS. Meanwhile, the mass and NMR spectroscopic analysis on the deamination products suggests that both type 1 Pn-PS and C-PS degraded following a major pathway of 5,4-hydride shift, cleavage of AAT O5-C1 bond, C1 hemiacetal formation, and its hydrolysis to release neighboring GalA- in type 1 Pn-PS and GalNAc(6-O-PCho)- in C-PS
Methods: 13C NMR, 1H NMR, gel filtration, sugar analysis, MS/MS, MS, dialysis, SEC-HPLC, ultrafiltration, mild deamination Comments, role: major oligosaccharide was obtained by mild deamination of the cell wall polysaccharide
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