Table 2.
A752 and U2609 nucleotide changes that affect tnaA’-‘lacZ expression in the bacterial cell
| 23S rRNAs | β-gal activity (Miller units)a ± SD |
Induction ration (+Trp/−Trp)b | |
|---|---|---|---|
| −Trp | +Trp | ||
| A752/U2609 (wt) | 120 ± 10 | 4500 ± 20 | 37.5 |
| A/U combination | |||
| A752/U2609A | 110 ± 12 | 100 ± 10 | 1.0 |
| A752U/U2609 | 130 ± 15 | 140 ± 20 | 1.1 |
| A752U/U2609A | 90 ± 10 | 200 ± 13 | 2.2 |
| G/C combination | |||
| A752/U2609C | 75 ± 10 | 85 ± 6 | 1.1 |
| A752G/U2609 | 150 ± 20 | 3500 ± 22 | 23.3 |
| A752G/U2609C | 120 ± 15 | 4200 ± 20 | 35.0 |
| A752C/U2609 | 120 ± 10 | 160 ± 10 | 1.3 |
| Other combinations | |||
| A752C/U2609A | 130 ± 9 | 140 ± 8 | 1.1 |
| A752C/U2609C | 110 ± 12 | 140 ± 10 | 1.3 |
| A752U/U2609C | 90 ± 9 | 100 ± 8 | 1.1 |
aCultures of SR-14 derived strains obtained by replacement of the prrnC-sacB plasmid by pK4–16 variants were grown in minimal medium plus 0.2% glycerol, 0.05% acid-hydrolyzed casein, 0.01% vitamin B1 and 50 µg/ml kanamycin with (+Trp) or without (−Trp) 100 µg/ml Trp. β-gal assays were performed in four independent experiments.
bRatio of values for cultures grown with Trp (+Trp) and those grown without Trp (−Trp).