[3)-beta-D-Galp-(1->4)-beta-D-Glcp-(1->6)-[beta-D-Galp-(1->4)]-beta-D-GlcpNAc-(1->]n
[3)-beta-d-galp-(1->4)-beta-d-glcp-(1->6)-[beta-d-galp-(1->4)]-beta-d-glcpnac-(1->]n
A polysaccharide derivative comprising a tetrasaccharide repeating unit consisting of a trisaccharide backbone of β-<small>D</small>-galactosyl, β-<small>D</small>-glucosyl and <em>N</em>-acetyl-β-<small>D</small>-glucosaminyl residues linked sequentially (1→4) and (1→6), with a further β-<small>D</small>-galactosyl residue linked (1→4) to the <em>N</em>-acetyl-β-<small>D</small>-glucosaminyl residue, and with the tetrasaccharide repeats themselves being linked (1→3); corresponds to the serotype 14 capsular polysaccharide (CPS) of <em>Streptococcus pneumoniae</em>. The structure diagram shows a portion of the polysaccharide chain consisting of three such tetrasaccharide repeating units showing clearly the (1→3) linkages existing between the repeating units.