title: Structural studies of the capsular polysaccharide from Streptococcus pneumoniae type 5.
abstract: The structure of the capsular polysaccharide (S5) elaborated by Streptococcus pneumoniae type 5 has been investigated by using n.m.r. spectroscopy, methylation analysis, and various specific degradations. It is concluded that the polysaccharide is composed of pentasaccharide repeating-units having the following structure: (Formula: see text) In this structure, L-PneNAc stands for 2-acetamido-2,6-dideoxy-L-talose (pneumosamine) and D-Sug for 2-acetamido-2,6-dideoxy-D-xylo-hexos-4-ulose. The latter sugar accounts for the lability of S5 towards alkali. N.m.r. spectra indicate heterogeneity in S5, most probably associated with the hexosyl-4-ulose residue.
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D009904:Optical Rotation; D011135:Polysaccharides, Bacterial / Q000302:isolation & purification*; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D002241:Carbohydrates; D011135:Polysaccharides, Bacterial