Wheat germ agglutinin was found to agglutinate cells of Escherichia coli PAT 84, Micrococcus luteus, Staphylococcus aureus H, and of S. aureus 52A5, but not cells of S. aureus 52A2.Interaction of wheat germ agglutinin with a soluble linear peptidoglycan secreted by Micrococcus luteus and with the teichoic acid of S. aureus H was demonstrated by agar gel diffusion, quantitative precipitation and inhibition of hemagglutination of trypsinized rabbit erythrocytes. No interaction could be demonstrated with the teichoic acid from a phage-resistant mutant ( S . aureus 52A2) which lacks N-acetyl-D-glucosamine residues.All interactions were specifically inhibited by low concentrations of chitotriose (GlcNAcPl -+ 4GlcNAcPI + 4GlcNAc) and the bacterial cell wall tetrasaccharide, GlcNAcfil -+ 4MurNAcfil + 4GlcNAcjll + 4MurNAc. Hemagglutination-inhibition experiments showed that the linear peptidoglycan and the teichoic acid of S. aureus H were several thousand times more potent inhibitors of wheat germ agglutinin than was N-acetyl-D-glucosamine.Comparison of the efficiency of different saccharides in inhibition of hemagglutination and precipitation of polymers by wheat germ agglutinin, strongly suggests that secondary, non-specific interactions contribute to the binding of the lectin to the polymers.Many lectins agglutinate bacteria and precipitate bacterial polysaccharides specifically [ 1,2]. As early as 1936, Sumner and Howell [3] observed that concanavalin A agglutinated various Mycobacteria. This agglutination is at least in part due to the interaction of concanavalin A with an arabinogalactan present in mycobacterial cell walls [4]. Concanavalin A also precipitated the polyglycosylglycerol phosphate teichoic acid from Bacillus subtilis 168 [5].The lectin from snail (Helix pomatia) precipitated lipopolysaccharides of rough mutants of Salmonella typhimurium [6], Streptococcal group C polysaccharide, and the teichoic acid of Staphylococcus aureus 3528 in which nonreducing a-N-acetyl-D-glucosaminyl groups are present, but did not precipitate the teichoic acids of S. aureus A1 in which j-N-acetyl-D-glucosaminyl groups are attached instead [7,8].Interesting reports on the binding of phytohemagglutinin the nitrogen-fixing Rhizobia have recently appeared, and it has been suggested that these interactions may be responsible for the beneficial symbiotic relationship between the bacteria and the plants.Because of the growing interest in lectins, and the fact that they are useful for structural studies of complex saccharides [l, 21, we have investigated the interaction of wheat germ agglutinin, a lectin specific for N-acetyl-D-glucosamine residues [ll], with several bacteria and bacterial polymers.
MATERIALS AND METHODS
MaterialsN-Acetyl-D-glucosamine was a gift from PfiZer Inc. It was recrystallized from ethanol/acetone to give a melting point of 202 -203 "C. Chitotriose, (GlcNAc~1+4GlcNAc~1-+4GlcNAc) isolated from chitin, GlcNAcfil+4MurNAc and GlcNAcPl+4MurNAc-Pl+4GlcNAcP1-+4MurNAc from cell walls of MicroEur. J. Biochem. 55 (1...