TABLE 2.
Effect of rpoB mutations on competencea
| Strain (rpoB allele) | Doubling time in GM-I medium (min) | Optical density at t0 in GM-I medium (Klett units) | No. of PheA+ transformants (per ml) | Total CFU/ml | Transformation efficiency relative to wild type |
|---|---|---|---|---|---|
| WN547 (wild type) | 45 | 94 | 1,325 | 1.20 × 108 | 1.0 |
| WN758 (Q469R) | 45 | 86 | 34 | 2.06 × 108 | 0.015 |
| WN759 (H482R) | 57 | 130 | 8 | 1.24 × 108 | 0.006 |
| WN760 (H482Y) | 51 | 100 | 44 | 3.08 × 108 | 0.013 |
| WN761 (S487L) | 45 | 48 | 0 | 2.4 × 107 | <0.004 |
a
One milliliter of competent cells, prepared in GM-I or GM-II medium containing 50 μg of tryptophan and phenylalanine per ml, was transformed with 50 ng of chromosomal DNA purified from strain 168, and PheA+ transformants were selected.