Binding of magnesium ions to cell walls of Bacillus subtilis W23 containing teichoic acid or teichuronic acid.
When grown in a chemostat under various nutritional conditions, cells of Bacillus subtilis W23 produce walls containing teichoic acid or teichuronic acid. The binding of Mg2+ to these walls and to the isolated anionic polymers in solution was measured by equilibrium dialysis. In solution the ribitol teichoic acid bound Mg2+ in the molar ratio Mg2+/P=1:1 with an apparent association constant (Kassoc.) of 0.61 X 10(3)M-1, and the teichuronic acid bound Mg2+ in the ratio Mg2+/CO2-=1.1, Kassoc.=0.3 X 10(3)M-1. Cell walls containing teichuronic acid exhibited closely similar binding properties to those containing teichoic acid; in both cases Mg2+ was bound in the ratio Mg/P or Mg/CO2- of 0.5:1 and with a greater affinity than displayed by the isolated polymers in solution. It was concluded that Mg2+ ions are bound bivalently between anionic centres in the walls and that the incorporation of teichoic acid or teichuronic acid into the walls gives rise to similar ion-binding and charged properties. The results are discussed in relation to the possible functions of anionic polymers in cell walls.
D000116:Acetylgalactosamine / Q000031:analogs & derivatives* / Q000378:metabolism; D001412:Bacillus subtilis / Q000378:metabolism*; D001665:Binding Sites; D002473:Cell Wall / Q000378:metabolism; D005688:Galactosamine / Q000031:analogs & derivatives*; D005965:Glucuronates / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D011188:Potassium / Q000378:metabolism; D013682:Teichoic Acids / Q000378:metabolism*
D005965:Glucuronates; D011135:Polysaccharides, Bacterial; D013682:Teichoic Acids; D010758:Phosphorus; D005688:Galactosamine; D008274:Magnesium; D000116:Acetylgalactosamine; D011188:Potassium