3-Deoxy-octulosonic-acid-containing hexasaccharide fragment of unusual core type isolated from Hafnia alvei 2 lipopolysaccharide

The hexasaccharide containing 3-deoxy-octulosonic acid (Kdo) was isolated from the carbohydrate material obtained after the mild acid hydrolysis of lipopolysaccharide of Hafnia alvei strain 2. The hexasaccharide was purified by gel filtration on Bio-Gel P-4 and P-2 columns. On the basis of sugar and methylation analyses, one- and two-dimensional NMR spectroscopic methods, the hexasaccharide was identified as formula: see text] The tetrasaccharide linked to position 7 of Kdo is also part of the sialic-acid-containing O-specific unit. Di-substitution of Kdo at positions 7 and 8 has not been previously reported.