FIG. 2.
Effect of TorRso overproduction and of deletions in the torE promoter region on tor-lacZ fusion expression in E. coli. The TorR binding site and the putative −10 box are underlined, and the transcription start point of torE is indicated by the arrow at +1. The 5" end of the cloned tor sequence is shown, whereas the 3" part of the tor region is not shown and corresponds to position +217 for pPTorso4 and +119 for pPTorso7 and pPTorso9, relative to the torE transcription start site. Strain LCB436 containing plasmid pRso2 (torRso) and a plasmid of the pPTorso series, as indicated, was grown anaerobically (−O2) or aerobically (+O2), in the presence (+) or absence (−) of 0.001% arabinose. β-Galactosidase activities of the plasmid-borne tor-lacZ fusions are expressed in Miller units. nd, not determined.