The primary structure of the acidic capsular antigen of Escherichia coli O8:K45:H9 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] The polysaccharide contains the uncommon amino sugar 3-acetamido-3,6-dideoxy-D- galactopyranose, which has not been previously identified in a capsular antigen.
E. coli O8:K45:H9
13C NMR data:
Linkage Residue C1 C2 C3 C4 C5 C6
3,4,2 Ac 175.06-175.15 ?
3,4,3,3 Ac 175.06-175.15 ?
3,4,3 bDFucp3N 104.55 69.06 55.63 70.63 72.85 16.22
3,4 aDGlcpN 99.40 53.07 81.32 69.14 71.43 69.23
3 bDGalpA 104.34 70.87 72.39 78.07 73.69 171.23
2 Ac 175.06-175.15 ?
bDGlcpN 102.28 55.43 84.68 69.88 76.32 61.77
1H NMR data:
Linkage Residue H1 H2 H3 H4 H5 H6
3,4,2 Ac - 2.02-2.06
3,4,3,3 Ac - 2.02-2.06
3,4,3 bDFucp3N 4.48 3.52 3.93 3.74 3.91 1.25
3,4 aDGlcpN 4.94 4.02 3.85 3.57 4.32 3.82-4.12
3 bDGalpA 4.55 3.62 3.83 4.38 4.44 -
2 Ac - 2.02-2.06
bDGlcpN 4.62 3.88 3.85 3.62 3.52 3.80-3.96
1H/13C HSQC data:
Linkage Residue C1/H1 C2/H2 C3/H3 C4/H4 C5/H5 C6/H6
3,4,2 Ac ?/2.02-2.06
3,4,3,3 Ac ?/2.02-2.06
3,4,3 bDFucp3N 104.55/4.48 69.06/3.52 55.63/3.93 70.63/3.74 72.85/3.91 16.22/1.25
3,4 aDGlcpN 99.40/4.94 53.07/4.02 81.32/3.85 69.14/3.57 71.43/4.32 69.23/3.82-4.12
3 bDGalpA 104.34/4.55 70.87/3.62 72.39/3.83 78.07/4.38 73.69/4.44
2 Ac ?/2.02-2.06
bDGlcpN 102.28/4.62 55.43/3.88 84.68/3.85 69.88/3.62 76.32/3.52 61.77/3.80-3.96
Found 
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