STRUCTURAL AND SEROLOGICAL STUDIES OF THE O-SPECIFIC POLYSACCHARIDE OF THE BACTERIUM PROTEUS-MIRABILIS-O10 CONTAINING L-ALTRURONIC ACID, A NEW COMPONENT OF O-ANTIGENS

An acidic O-specific polysaccharide from the lipopolysaccharide of Pro teus mirabilis O10 contains 2-acetamido-2-deoxy-D-glucose, 2-acetamido -2-deoxy-D-galactose, D-galacturonic acid, and L-altruronic acid, the last-named sugar hating not been found hitherto in O-antigens. Structu re of a branched tetrasaccharide repeating unit of the polysaccharide was established by H-1 and C-13 NMR spectroscopy, including two-dimens ional COSY and rotating-frame NOE spectroscopy. The lateral L-altruron ic acid residue plays the immunodominant role in manifestation of the O10 specificity of Proteus, whereas a disaccharide fragment of the mai n chain in common with the O-specific polysaccharide of P. mirabilis O 43 provides the one-way serological cross-reactivity between anti-O10 serum and O43-antigen.