Interaction of concanavalin A with the cell wall of Bacillus subtilis

Interactions between concanavalin A and cell wall digests of Bacillus subtilis 168 resulted in insoluble complexes as observed by double gel diffusion, turbidity, and analysis of the precipitate. The macromolecular constituent of the cell walls complexing with concanavalin A was the polyglucosylglycerol phosphate teichoic acid. The complex exhibited two pH optima: 3.1 and 7.4. The complex could be dissociated by saccharides which bind to concanavalin A. In contrast to concanavalin A-neutral polysaccharide complexes, formation of the concanavalin A-wall complex was inhibited by salts. It was subsequently shown that salts induce conformational changes in cell wall digests. The data suggested that for complex formation to occur a rigid rod conformation in the glucosylated teichoic acid is probably necessary. Concanavalin A can be used as a probe to study structural features of bacterial cell walls.