FIGURE 5.
LC-MS analysis of cell extract from MupG complemented mutant. S. aureus ΔmupG cells transformed with the control pCtufamp plasmid (ΔmupG + pCtufamp) or with the mupG complementation plasmid pCtufamp-mupG (ΔmupG + pCtufamp-mupG) were grown for 24 h. Cytosolic fractions were analyzed by LC-MS in positive ion-mode. (A) Mass spectra of the samples were presented as base peak chromatograms (BPC × 105 counts per s [cps]) in black and as extracted ion chromatograms (EIC × 105 [cps]) for MurNAc 6P-GlcNAc with observed mass of (M+H)+ = 577.162 m/z in red. (B) MupG complementation experiment was performed in triplicates and the relative amount of the MurNAc 6P-GlcNAc in the cells was determined by calculating the area under the curve (AUC) of the respective EIC spectra.