Structural elucidation of the capsular polysaccharide from Streptococcus pneumoniae serotype 47A by NMR spectroscopy

The structure of the capsular polysaccharide from Streptococcus pneumoniae serotype 47A was elucidated by NMR spectroscopy. The structure shown above of the repeating heptasaccharide was deduced. The capsular polysaccharide 47A is one out of a total number of 91 structurally and serologically distinct capsular polysaccharides that have been recognized in S. pneumoniae, a significant human pathogenic bacterium. •We assigned the NMR spectra’s of S. pneumoniae serotype 47A.•We established the structure of S. pneumoniae serotype 47A.•We compared the structural assignment with known serotypes.•We found a new substitution pattern for the β-Galf compared with known serotypes. The structure of the serotype 47A (Danish nomenclature system) capsular polysaccharide from Streptococcus pneumoniae was elucidated by NMR spectroscopy. The following structure of the repeating heptasaccharide was deduced:▪ The serotype 47A capsular polysaccharide is one of 91 structurally and serologically distinct capsular polysaccharides that have been recognized in S. pneumoniae, a significant human pathogenic bacterium and model system in medical microbiology. Structure and NMR spectra are compared to previously solved capsular polysaccharide structures of other serotypes.