Extended Data Fig. 9: Inhibition of MRSA growth by combination treatment of norfloxacin and a CDRH3 mimicking peptide targeting NorA.
From: Structural basis for inhibition of the drug efflux pump NorA from Staphylococcus aureus
a. Analytical HPLC traces (top row) and MALDI-TOF (bottom row) of purified NPI-1, NPI-2, and FITC-NPI-1 peptides. NPI-1: observed mass of 1802.05 [M + H]+; calculated mass of 1801.85 [M + H]+. NPI-2: observed mass of 1775.07 [M + H]+; calculated mass of 1774.79 [M + H]+. FITC-NPI-1: observed mass of 2263.76 [M + H]+; calculated mass of 2263.95 [M + H]+. b, c. Growth inhibition of MRSA or MRSAΔnorA treated with varying concentrations of (b) NPI-1 or (c) NPI-2 in the presence or absence of norfloxacin (12.5 μg/ml). The peptide was added at the start of the time course (Time = 0-h). Solid lines and shading in the same color correspond to the average and standard deviation of three independent experiments, respectively. d. Growth inhibition of MRSA or MRSAΔnorA at the 10-h timepoint from (b) and (c) plotted against the NPI-1 (left) or NPI-2 (right) concentration, respectively. Data are presented as mean values ± s.d. among three independent experiments. The fitted curve was used to determine the IC50 for NPI-1 (0.72 ± 0.08 μM).
