Effects of lipopolysaccharide chemotype structure on binding and inactivation of hen egg lysozyme

The structural features of lipopolysaccharide [LPS] which influence the binding and inactivation of lysozyme have been examined. Binding of polysaccharide-containing LPS (S-LPS) and Ra-Rc-LPS preparations was independent of temperature between 37-50 degrees C; in contrast, binding of Rd-LPS, Re-LPS and lipid A was temperature-dependent. The binding of lysozyme to Rd-LPS and Re-LPS was increased by treatment with mild alkali, which has little detectable effect on binding of lysozyme to S-LPS and Ra-Rc-LPS preparations. Competitive binding experiments using dansylated lysozyme and/or dansylated polymyxin B indicated independent binding sites on the LPS for lysozyme and polymyxin B. These results indicate significant differences between most LPS preparations and lipid A and glycolipid LPS in their interaction with proteins of mammalian origin.