Table 2.
The effect of tri-alanine substitutions of σ70 R4 on basal transcription from the class II fumC, inaA and micF promoters.
| Tri-Alanine Stretches ofσ70R4 | β-galactosidase activity (% of wild type) | ||
|---|---|---|---|
| fumC | micF | inaA | |
| P531A-D533A | 134 ±6 | 132 ±18 | 124 ±4 |
| S534A-T536A | 98 ±15 | 88 ±10 | 118 ±5 |
| T537A-S539A | 81 ±13 | 84 ±11 | 137 ±8 |
| L540A-A542A | 88 ±22 | 125 ±9 | 116 ±4 |
| A543A-H545A | 116 ±18 | 105 ±14 | 98 ±4 |
| D46A-L548A | 56 ±5 | 100 ±7 | 117 ±6 |
| A549A-L551A | 174 ±18 | 121 ±10 | 92 ±4 |
| T552A-R554A | 177 ±13 | 107 ±4 | 97 ±6 |
| E555A-K557A | 10 ±12 | 122 ±10 | 110 ±3 |
| V558A-R560A | 151 ±8 | 108 ±8 | 89 ±9 |
| M561A-F563A | 59 ±5 | 130 ±6 | 120 ±6 |
| G564A-D566A | 82 ±6 | 130 ±4 | 124 ±3 |
| M567A-T569A | 72 ±10 | 137 ±5 | 73 ±8 |
| D570A-T572A | 215 ±14 | 183 ±13 | 126 ±5 |
| L573A-E575A | 90 ±17 | 163 ±8 | 104 ±5 |
| V576A-K578A | 62 ±3 | 209 ±24 | 86 ± 7 |
| Q579A-D581A | 290 ±14 | 208 ±8 | 100 ±3 |
| V582A-R584A | 64 ±7 | 135 ±4 | 108 ±6 |
| E585A-I587A | 54 ±5 | 156 ±7 | 75 ±4 |
| R588A-I590A | 219 ±18 | 169 ±7 | 78 ±3 |
The experiments were carried out with the same class II fusion strains and under the same conditions as those described in Table 1, except that no arabinose was added to the cultures such that SoxS expression was not induced. Expression of the fusions was determined by assay of β-galactosidase activity as described in Materials and Methods. The data are expressed as the % of the wild type value and the standard deviations are given as the % of the mean. Wild type Miller units at SoxS dependent promoters were fumC (287), inaA (77) and micF (123). As described in the text, values for mutants that are ≤ 80% of the wild type activity are taken as a meaningful difference; these values are in bold and are highlighted in grey.