Kinetic analysis of LmrP-mediated, facilitated ethidium influx and efflux.

<p><b>A</b>, The ethidium influx rates in ATP-depleted cells were measured as a function of the ethidium concentration. Each data point represents the mean ± SEM of four independent experiments (n = 4). <b>B,</b> Comparison of V_max of the K357A or R260A mutant with that of Wt LmrP. The data were analysed by one-way ANOVA followed by the post-hoc Tukey’s test. **P<0.01, ***P<0.001, both significantly different. <b>C,</b> Comparison of K_m for ethidium of the K357A or R260A mutant with that of Wt LmrP. Analysis by one-way ANOVA shows that K_m values are not significantly different. <b>D,</b> The efflux rates in ATP-depleted cells were measured as a function of the ethidium concentration. Each data point represents the mean ± SEM of three independent experiments (n = 3). <b>E,</b> Comparison of V_max of K357A or R260A mutant with that of Wt LmrP. The data were analysed by one-way ANOVA followed by the post-hoc Tukey’s test. *P<0.05, significantly different. <b>F,</b> Comparison of K_m of the K357A or R260A mutant with that of Wt LmrP. K_m values were not significantly different when the data were analysed by one-way ANOVA.