FIG. 2.

Sequences of single-point mutants with mutations in the region from −80 to −30, aligned with the sequence of the wild-type tcpA promoter. Base pair changes or deletions are shown; wild-type bases are indicated by dots. Strains carrying the tcpA-lacZ fusions on plasmid pRS415 with no ToxT or with the ToxT-expressing plasmid pTSS-5 were grown overnight in LB medium (pH 6.5) at 30°C. The β-galactosidase activity (in Miller units) and the level of activation (act.) in the presence of ToxT are shown for each strain. The values are averages for at least two independent experiments.