Identification of Phosphorylation Sites in Polysaccharides by 1-D1H-31P HMQC Experiments

Phosphoric ester groups are found in many bacterial polysaccharides. They may occur as phosphomonoesters, but more often, they appear as phosphodiesters. The reducing end of some polysaccharides, e.g., several capsular polysaccharides from Escherichia coli and Neisseria species, 12 is linked to O-1 of a 2,3-di-O-acylglycerol through a phosphodiester linkage. A few pneumococcal polysaccharides are substituted by choline phosphate, 3 an immunologically significant substituent. The cell-wall polysaccharide from Bacillus cereus AHU 1356, 4 the extracellular polysaccharide from Streptococcuspneumoniae type 11A, 5 and the capsular polysaccharide from S. pneumoniae type 23F 6 contain glycerol phosphate diesters. There are also examples of substitution by ribitol phosphate, such as the capsular polysaccharide from S. pneumoniae type 11F. 7 The repeating units of teichoic acids are linked by phosphodiester linkages. Examples are the capsular antigens of Neisseria meningitides type A 8 and Haemophilus influenzae type c. 9 Glycerol phosphate comprises part of the polysaccharide backbone of the capsular polysaccharide from N. meningitidis type Z. 10 Ribitol phosphate is part of the backbone of the capsular polysaccharides of S. pneumoniae type 34 11 and H inzuenzue type a. 12 Other alditol phosphates rarely occur in polysaccharides. 13,14