FIG 2.

Mutations in SoxR confer resistance to doxycycline. (A) Verification of mutations enriched in the regulator library for resistance to doxycycline at a 25-μg/ml concentration. (B) The regulation network of SoxR control genes involved in multidrug efflux pumps and expression of porins. (C) Fold change in the levels of expression of SoxR-regulated genes in the SoxR G121K, I120E, G121N, and G121P mutants relative to their expression in strain MG1655 under a doxycycline concentration of 15 μg/ml. (D) The positions of mutated residues in the SoxR structure (blue). The ligand [2Fe-2S] is shown in red (PDB accession number 2ZHH).