FIGURE 2.
E. coli PBP1b glycosyltransferase pyrophosphate sensor and thermal aggregation assays. A, schematic representation of pyrophosphate sensor assay. B, substrate concentration response experiment. Various concentrations of lipid II were added to 1 μm of PBP1b. C, PBP1b GTase moenomycin complex inhibition assays. IC50 experiments were performed using 1 μm of enzyme and 45 μm lipid II. D, thermal stabilization of PBP1b in the presence of moenomycin complex. Thermostability of PBP1b was assessed at various moenomycin complex concentrations by differential static light scattering as a measure of the change in thermal aggregation (Tagg) to calculate the aggregation constant (Kagg) for the interaction (see “Experimental Procedures”). All error bars represent standard deviation from triplicate technical replicates.