Relation between wall teichoic acid content and Concanavalin A binding in Bacillus subtilis 168

Abstract

It has been known for some time that Concanavalin A will agglutinate bacteria whose wall teichoic acids contain a-linked glucosyl substituents [1]. The ability of the lectin to precipitate appropriately substituted teichoic acids has been used in structural [2] and preparative [3] studies and its interaction with whole bacteria or isolated walls has been studied in attempts to gain information on the location of teichoic acids in the cell wall and at the bacterial surface [4,5]. Interpretation of the latter studies has been complicated by the lack of any information on how the amount of Concanavalin A bound is related to the amount of teichoic acid present in the bacteria, or whether variations in the amount of teichoic acid present affect both the amount bound and the affinity of binding. We have recently [6] shown that the amount of teichoic acid present in walls of B. subtilis 168 can be controlled by growing the bacteria under balanced conditions with varied phosphate supply. We now report a study of the interaction of these bacteria with Concanavalin A. Our results show that the association constant of the binding reaction is little affected by variation in teichoic acid content but the amount of Concanavalin A bound increases in proportion to the amount of teichoic acid present although it ap-