Structural studies of the capsular polysaccharide elaborated by Haemophilus influenzae type d

The structure of the capsular polysaccharide elaborated by Haemophilus influenzae type d has been investigated, methylation analysis and n.m.r. spectrometry being the principal methods used. It is concluded that the polysaccharide is composed of repeating units having the structure: →4)-β-d-GlcpNAc-(1→3)-β-d-ManpNAcA-(1→. In addition, single residues of l-alanine, l-serine, or l-threonine, in the proportions 2:2:1, are linked, through their amino groups, to C-6 of the 2-acetamido-2-deoxy-β-d-mannopyranosyluronic acid residues. The degree of substitution (75-85%) varies for different preparations.