The alanine ester content and magnesium binding capacity of walls of Staphylococcus aureus H grown at different pH values

Abstract

Recent studies have shown that teichoic acids are functionally involved in the uptake of Mg 2+ and that their ability to bind Mg is reduced by the presence of alanine ester substituents. Walls of Staphylococcus aureaus H grown at pH 5 contain more ester alanine and bind less magnesium than do walls of S. aureaus grown under similar conditions at pH 6 and 7. The differences in alanine content are largely due to its removal by base catalysed hydrolysis of the labile ester linkages during growth in media of pH 6 and 7 and the incorporation of alanine esters into the walls does not appear to be influenced by the pH of the medium in which the bacteria are grown under the conditions described. The decreased magnesium binding capacity of walls of S. aureus grown at pH 5 correlates with their increased alanine ester content but there is no proportional relationship between these two quantities.