TABLE 2.
ExbB and ExbD complementation assaysa
| Strain (plasmid[s]) | Relevant genotype | Dilution resulting in clearance by:
|
||
|---|---|---|---|---|
| Colicin B | Colicin D | Phage φ80 | ||
| GM1 | Wild type | ND | ND | 109 |
| KP1269(pKP298) | exbBD+ | 57 | 56 | 109 |
| KP1269(pKP339/pKP360) | T7exbB+exbD+ | 56 | 55 | 106 |
| KP1269(pKP323/pKP361) | T7exbD+exbB+ | 56 | 55 | 107 |
| KP1269[pET-24(a)+/ pACYC184] | ΔexbBD | 54 | 53 | 104 |
a
ExbBD activity was measured by sensitivity to colicins B and D and phage φ80. The results for colicins B and D indicate the final dilution that resulted in complete clearing of the indicator strain. The results for phage φ80 indicate the first dilution that resulted in no plaques being formed on the indicator strain. In both cases, lower numbers indicate higher levels of TonB (and thus ExbBD) function. All assays were performed in triplicate and gave identical results. ND, not done.