Figure 3 .

(A) β-galactosidase assay measurement of the activation of PpbrA, containing a 1 nt deletion in the 19 bp promoter spacer, to increasing levels of Pb(II) inC. metalliduransAE104 carrying pMUPbrRpbrA-1. Micromolar Pb(II) concentrations are indicated by the suffix to Pb on the abscissa. Pb0 contains no added Pb(II), Pb200 contains 200 μM Pb(II) . The sequence of wild-type PpbrA and the −1 mutant PpbrA are shown below the graph. The −35 and −10 sequences are marked in BOLD. Arrows show dyad symmetrical DNA sequences within the promoters. (B) β-galactosidase assay measurement of the activation of −10 sequence mutant PpbrA clones in pMU2385 in response to no added Pb(II) or 100 μM Pb(II). WT denotes wild-type −10 sequence (TTAAAT), CON denotes the E. coli consensus promoter −10 sequence (TATAAT) and MER the Tn501 PmerT promoter −10 sequence (TAAGGT). The sequences of the wild-type (PpbrA wt), consensus (PpbrA con), and PmerT-like promoters (PpbrA mer) are shown below the graph. The −35 and −10 sequences are marked in BOLD. Arrows show dyad symmetrical DNA sequences within the promoters, and altered bases are marked in Gray.

Hobman et al. BMC Microbiology 2012 12:109   doi:10.1186/1471-2180-12-109
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