<p><b>A.</b> Inhibitory activity of δ-toxin against PSMα2 binding to the <i>S</i>. <i>aureus</i> cell surface of the PSMα1-4/δ-toxin knockout strain was measured. Binding assay of PSMα2 (10 nmol) to the cell surface of the PSMα1-4/δ-toxin knockout strain was performed in the absence or presence of δ-toxin (0, 10, 20, and 30 nmol) and the amount of PSMα2 bound to the cell surface was measured (left graph). In the competition assay, the binding of δ-toxin to the <i>S</i>. <i>aureus</i> cell surface was also measured (center graph) and the binding of total PSM (PSMα2 and δ-toxin) is presented (right graph). In all graphs, horizontal axis represents the amount of PSM added to <i>S</i>. <i>aureus</i> cells and vertical axis represents the amount of PSM bound to <i>S</i>. <i>aureus</i> cells (3 x 10<sup>8</sup> CFU). B. Inhibitory activity of PSMα2 against δ-toxin binding to the <i>S</i>. <i>aureus</i> cell surface was measured. Binding assay of δ-toxin (10 nmol) to the cell surface of the PSMα1-4/δ-toxin knockout strain was performed in the absence or presence of PSMα2 (0, 10, 20, and 30 nmol) and the amount of δ-toxin bound to the cell surface was measured (left graph). In the competition assay, binding of PSMα2 to the <i>S</i>. <i>aureus</i> cell surface was also measured (center graph) and the binding of total PSM (δ-toxin and PSMα2) is presented (right graph). C. Inhibitory activity of δ-toxin against PSMα3 binding to the <i>S</i>. <i>aureus</i> cell surface was measured. Binding assay of PSMα3 (10 nmol) to the cell surface of the PSMα1-4/δ-toxin knockout strain was performed in the absence or presence of δ-toxin (0, 10, 20, and 30 nmol) and the amount of PSMα3 bound to the cell surface was measured (left graph). In the competition assay, binding of δ-toxin to the <i>S</i>. <i>aureus</i> cell surface was also measured (center graph) and the binding of total PSM (PSMα3 and δ-toxin) is presented (right graph). D. Inhibitory activity of PSMα3 against δ-toxin binding to <i>S</i>. <i>aureus</i> cell surface was measured. Binding assay of δ-toxin (10 nmol) to the cell surface of the PSMα1-4/δ-toxin knockout strain was performed in the absence or presence of PSMα3 (0, 10, 20, and 30 nmol) and the amount of δ-toxin bound to the cell surface was measured (left graph). In the competition assay, binding of PSMα3 to the <i>S</i>. <i>aureus</i> cell surface was also measured (center graph) and the binding of total PSM (δ-toxin and PSMα3) is presented (right graph).</p
