Chemical structures of acholeplasmal lipoglycans and their relation to biological interactions.

The partial characterization of the structure of the lipoglycan (LG) from Acholeplasma axanthum is added to the previous complete structural analysis of the lipoglycan from A. granularum. The terminal sequence of A. axanthum LG is Glcp(beta 1----2)-Glcp(beta 1----2)-Glcp(beta 1----6)-; of A. granularum Glcp(beta 1----2)-Glcp(alpha 1----4)-Glcp(beta 1----4)-. These specific residues define the major antigenic determinants of the LG as determined by blockage of hemagglutination of LG coated erythrocytes by specific oligosaccharides and binding of radiolabeled LG to specific immunoglobulins. The binding of LG to mammalian cells occurs by an interaction between specific eucaryotic cell receptors and the internal sequence of the oligosaccharide chain of LG. Size and sugar chains of LG rather than fatty acid residues appears to define the binding site on the LG.