Structure and molar mass analysis of pneumococcal capsular polysaccharides by 1H NMR and HPSEC-MALLS

Abstract

Objective To analyze the structures and molecular weight distributions of the capsular polysaccharides from 6 serotypes of pneumococcus .Methods The structures of pneumococcal capsular pol-ysaccharides of 6 serotypes were analyzed by 1 H nuclear magnetic resonance （ NMR） .Chemical shifts of all characteristic protons were investigated to analyze polysaccharide integrity and inter -assay consistency .High performance size exclusion chromatography-multi angle laser light scattering （ HPSEC-MALLS） was used to measure the molecular weights .Results The chemical shifts of all characteristic protons of the pneumococ-cal capsular polysaccharides of 6 serotypes were consistent with the standard chemical shift .The weight-aver-age molecular mass of the pneumococcal capsular polysaccharides ranged from 7.182×104 g/mol（for serotype 19A） to 1.273×106 g/mol（for serotype 9V）examined by HPSEC-MALLS.Conclusion The structures and molecular weight distributions of pneumococcal capsular polysaccharides could be rapidly and effectively ana -lyzed by 1 H NMR and HPSEC-MALLS.Moreover, C-PS and acetate contained in capsular polysaccharides could also be detected .HPSEC-MALLS is an applicable method for the quantitative analysis of molar mass distributions in different serotypes of pneumococcal capsular polysaccharides . Although 1 H NMR and HPSEC-MALLS have been accepted as the quality control measurements by WHO , to use them as the re-placements of the traditional QC method still needs further investigation . Key words: Pneumococcal capsular polysaccharide; 1 H NMR; Chemical structure; HPSEC-MALLS; Weight-average molecular mass