Erratum to: Multidrug resistance protein MdtM adds to the repertoire of antiporters involved in alkaline pH homeostasis in Escherichia coli

Erratum

It has been brought to our attention after publication that there is an error in Fig. 2 of our article [1]. The panel in Fig. 2a which purported to show the growth phenotypes of E.coli BW25113 cells transformed with plasmids pMdtM and pD22A at logarithmic dilutions of 10^–3 to 10^–5 at pH 9.75 actually showed the 10^–4 to 10^–6 logarithmic dilutions of cells grown at pH 9.5. The offending panel has been removed and the correct panel, which shows the growth phenotypes of transformants at logarithmic dilutions of 10^–3 to 10^–5 at pH 9.75, has been incorporated into the new Fig. 2 shown at the end of this erratum. The figure legend remains unchanged. This error does not affect the other results or any of the conclusions of the article.

Fig. 2

E. coli ΔmdtM cells complemented with wild-type mdtM can grow at alkaline pH. a Growth phenotypes of ΔmdtM E. coli BW25113 cells transformed with a multicopy plasmid encoding wild-type MdtM (pMdtM) or the dysfunctional MdtM D22A mutant (pD22A) at different alkaline pH’s on LB agar. As indicated, 4 μl aliquots of a logarithmic dilution series of cells were spotted onto the solid media and the plates were incubated for 24 h at 37 °C prior to digital imaging. b Growth of ΔmdtM E. coli BW25113 cells complemented with pMdtM or the pD22A mutant in liquid LB media at different alkaline pH values. Data points and error bars represent the mean ± SE of three independent measurements. c Comparison of expression levels of recombinant wild-type and D22A mutant MdtM at three different pH values by Western blot analysis of DDM detergent-solubilised membranes of E. coli BW25113 cells that overproduced the protein from plasmidic DNA. Cells harbouring empty pBAD vector were used as a negative control. Each lane contained 10 μg of membrane protein