School of Pharmaceutical Sciences, Rhodes University, Grahamstown 6140 South Africa
The primary structure of the acidic capsular antigen of Escherichia coli O20:K101 was shown by glycose analysis, methylation analysis, and one- and two-dimensional 1H and 13C NMR spectroscopy to be composed of repeating branched-tetrasaccharide units having the structure: (formula; see text).
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
3,4,2 Ac 175.25-175.53 ?
3,4 bDGalpN 102.16 51.86 80.85 68.69 75.74 61.92
3,3,2 Ac 175.25-175.53 ?
3,3 bDGlcpN 102.69 56.92 74.62 71.21 77.06 62.01
3 bDGlcpA 103.17 75.36 81.35 80.47 75.58 172.07
bDGalp 104.77 70.49 84.59 68.69 75.58 61.88
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
3,4,2 Ac - 2.03-2.06
3,4 bDGalpN 4.57 4.02 3.88 4.18 3.73 3.82-3.82
3,3,2 Ac - 2.03-2.06
3,3 bDGlcpN 4.85 3.68 3.59 3.39 3.48 3.74-3.94
3 bDGlcpA 4.75 3.66 3.67 3.83 3.72 -
bDGalp 4.52 3.69 3.71 4.11 3.64 3.73-3.73
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
3,4,2 Ac ?/2.03-2.06
3,4 bDGalpN 102.16/4.57 51.86/4.02 80.85/3.88 68.69/4.18 75.74/3.73 61.92/3.82-3.82
3,3,2 Ac ?/2.03-2.06
3,3 bDGlcpN 102.69/4.85 56.92/3.68 74.62/3.59 71.21/3.39 77.06/3.48 62.01/3.74-3.94
3 bDGlcpA 103.17/4.75 75.36/3.66 81.35/3.67 80.47/3.83 75.58/3.72
bDGalp 104.77/4.52 70.49/3.69 84.59/3.71 68.69/4.11 75.58/3.64 61.88/3.73-3.73
Found 
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