TABLE 3.
FecI-binding and induction activity of the wild-type and the mutated fecA promoter regionsa
| Plasmid | Base changes | β-Galactosidase activity (percent FecI-binding)
|
Relative fluorescence (percent induction)
|
||
|---|---|---|---|---|---|
| NB medium | NB medium + 1 mM citrate | NB medium | NB medium + 1 mM citrate | ||
| pBCSK+ | 108 | 325 (0) | 181 | 224 | |
| pHCA | Wild type | 94 | 192 (100) | 258 | 2,636 (100) |
| pHC10 | A−31C | 105 | 246 (60) | 255 | 1324 (50) |
| pHC29 | T−12G | 138 | 307 (14) | 178 | 909 (34) |
| pHC50 | G+10 T | 125 | 241 (63) | 160 | 234 (9) |
a
Values (in Miller units) were determined for E. coli ZI418 fecB-lacZ transformed with high-copy-number plasmids carrying the fecA wild-type promoter or fecA mutant promoter fused to gfp.