Polyelectrolyte Nature of Bacterial Teichoic Acids

Abstract

Several physicochemical properties of the teichoic acid of Bacillus subtilis 168 have been determined. The teichoic acid partial specific volume was found to be 0.57 ml/g. The apparent weight-average molecular weight of the polymer was 24,800. Sedimentation was strongly dependent on solvent. The sedimentation coefficient of the teichoic acid was found to have a value of s 20.w 0 = 1.90 S . In dilute buffers and distilled water, the teichoic acid possessed a rigid rod or extended conformation. Salts induced a loss of secondary structure in the polymer, resulting in a random coil configuration. Salt-induced structural changes in the teichoic acid were determined by viscosities, ultraviolet difference spectra, and inhibition of precipitation with concanavalin A. Divalent cations such as Mg 2+ had little effect on the teichoic acid structure. The salt-induced structural changes were reversible, as evidenced by return of the original properties upon dialysis of the teichoic acid against water. Sodium chloride inhibited the adsorption of bacteriophage ø25 to B. subtilis cell walls. Teichoic acid conformation may have a significant influence on the physiology of bacteria.