The Wall Teichoic Acid Polymerase TagF Efficiently Synthesizes Poly(glycerol phosphate) on the TagB Product Lipid III

Abstract

Our understanding of the function of cell-wall teichoic acid polymerases such as TagF from Bacillus subtilis has been limited by the tools available for a functional assay. Teichoic acid polymerase activity has previously been studied by using crude membrane preparations as a source of substrate(s). Thus, an understanding of the most basic features of the teichoic acid polymerization has eluded characterization. Here we make use of a soluble synthetic glycolipid to provide the first demonstration that TagF polymerizes glycerol phosphate directly on the product of TagB—teichoic acid lipid III—at a rate approximately 100 times higher than observed with crude membrane preparations. Interestingly, polymer length was determined by the ratio of glycolipid acceptor to CDP-glycerol, implying that polymerization occurs in a distributive manner. This work provides new insights into the reaction catalyzed by TagF, a prototypic teichoic acid polymerase. The bacterial cell wall has been a popular target for the design of antibacterial agents. Nevertheless, cell wall-active antibiotics have exclusively targeted peptidoglycan synthesis and thus overlook other cell wall components. In Gram-positive bacteria, cell wall teichoic acids are a chemically diverse group of phosphate-rich polymers that are covalently linked to peptidoglycan. Wall teichoic acid accounts for up to 60 % of the Gram-positive cell-wall dry weight. [1] Indeed, wall teichoic acid has recently been shown to be essential to the proper rodshaped morphology of Bacillus subtilis [2] and a key virulence determinant for the human pathogen Staphylococcus aureus. [3, 4] Wall teichoic acid synthesis is thus an emerging