Substrate accessibility of residues lining up the substrate translocation pathway in the triple knockout strain and in AcrB_D407A.

<p><b>A.</b> Representative gel images. For each position tested, the bottom panel (F) is the fluorescence image before staining and the top panel (CB) is the image of the same gel after Coomassie blue stain. Labeling of mutants containing Cys at the indicated site on the background of _CLAcrB in MG1655<i>ΔacrB</i> (lane C) or MG1655<i>ΔacrABtolC</i> (lane 1), and _CLAcrB_D407A in MG1655<i>ΔacrB</i> (lane 2). <b>B.</b> Relative percentage of labeling for each site in <i>acrABtolC</i> knockout strain as compared to <i>acrB</i> knockout strain (black), and in _CLAcrB_D407A as compared to in _CLAcrB (grey). Each experiment was performed three times. The average value and standard deviation were shown. <b>C.</b> Representative gel images of labeling in the absence (lane C) or presence of over-expressed AcrA (lane 1) or TolC (lane 2). Gels were labeled similarly as above.