Fig. 4: Comparison of MCX-190 and WT/15B196 S. aureus ribosome complexes.

a The results of in vitro translation inhibition assays showed that 15B196 ribosomes were sensitive to MCX-219 and MCX-190. IC₅₀ Values are shown as mean ± SD of at least three independent experiments. b Q-TOF mass spectrometry analysis of S. aureus rRNA 2052–2064. In the triply deprotonated ion of the molecule, the fragment GGACGGAAAGACC runs at 1433.54 m/z (when unmethylated). Monomethylation and dimethylation at A2058 result in mass shifts to 1438.21 m/z and 1442.89 m/z, respectively. The unmethylated fragment with a Na ion is observed at 1440.87 m/z. c The density maps of A2058 (A2085) in the 15B196/WT S. aureus ribosome complex. Both of two density maps of are contoured at 7.5σ. d The density of the desosamine in the complex of 15B196 ribosome complex was significantly decreased, compared to the WT ribosome complex. e The π–π interaction of quinolone ring with A2062 (A2089) and C1782–C2586 (C1809–C2613), was not affected by whether A2058 (A2085) was methylated.