Figure 3.

The lytic and binding specificities of SpM23_A and SpM23_B toward bacterial strains that harbor their respective coding genes. (A) Comparison of the lytic activity and the net charge on the surface of Staphylococcus pettenkoferi strain cells. The net charge was estimated by cytochrome c (Cyt C) assay performed in ammonium acetate buffer, pH 4.6. Lytic activity was measured based on decreases in OD₆₀₀ values after 1h of reaction. Bacteria resuspended in reaction buffer without the addition of the lytic enzyme served as the negative control; the reductions in OD₆₀₀ values in this sample were subtracted from the presented values. The assay was performed in 50mM glycine buffer, pH 8.0. All the experiments were performed three times. (B) A binding assay was performed on a set of S. pettenkoferi strains and S. argensis to compare the binding efficiencies of recombinant CBD_A and CBD_B fused to GFP. The fluorescence of the negative control (GFP alone) was subtracted from the presented results. The assay was performed in PBS, pH 7.2, at room temperature. Fluorescence was measured with excitation at the 488nM wavelength and emission at the 508nM wavelength.