Table 4.
Suppression of the H20X substitutions by ExbB(A39E)
| Mutant typea | Sensitivity tob: |
||||
|---|---|---|---|---|---|
| Colicin B | Colicin D | Colicin M | Colicin Ia | φ80 | |
| Chromosomal | 9, 9, 9 | 7, 7, 7 | 6, 5, 5 | 9, 9, 9 | 8, 8, 8 |
| pKP325 (wild type) | 8, 8, 7 | 6, 7, 6 | 3, 5, 5 | 7, 7, 7 | 8, 7, 7 |
| ΔtonB | T, T, T | T, T, T | T, T, T | T, T, T | T, T, T |
| ΔV17 | 4*, 4*, 4* | 3, 3, 3 | T, T, T | T, T, T | 3, 3, 5 |
| H20A | T, T, T | T, T, T | T, T, T | T, T, T | 6, 7, 8 |
| H20C | 3*, 4*, 4* | T, T, T | T, T, T | 4*, 3*, 3* | 7, 6, 6 |
| H20D | 4*, 4*, 5* | 4, 4, 3 | 0*, 2*, 2* | T, T, 2 | 3, 5, 3 |
| H20E | 7, 7, 7 | 5, 6, 7 | 3, 3, 4 | 6, 6, 6 | 8, 7, 7 |
| H20F | T, T, T | T, T, T | T, T, T | T, T, T | 5, 5, 5 |
| H20G | T, T, T | T, T, T | T, T, T | T, T, T | 2, 3, 3 |
| H20I | T, T, T | T, T, T | T, T, T | T, T, T | 4, 5, 6 |
| H20K | T, T, T | T, T, T | T, T, T | T, T, T | 6, 5, 5 |
| H20L | T, T, T | T, T, T | T, T, T | T, T, T | 6, 6, 6 |
| H20M | 4*, 3*, 4* | 3, 3, 3 | T, T, T | 3*, 2*, 2* | 6, 7, 8 |
| H20N | 8, 9, 8 | 5, 6, 6 | 4, 5, 5 | 7, 7, 7 | 8, 7, 7 |
| H20P | T, T, T | T, T, T | T, T, T | T, T, T | 5, 7, 7 |
| H20Q | 7, 7, 7 | 3, 3, 4 | 2*, 3*, 3* | 4, 5, 5 | 4, 4, 5 |
| H20R | 7, 7, 7 | 5, 5, 5 | 5, 5, 5 | 6, 6, 6 | 7, 8, 8 |
| H20S | 4*, 4*, 4* | 3*, 3*, 2* | 2*, 3*, 3* | 3*, 2*, 3 | 7, 8, 7 |
| H20T | 5*, 6*, 7* | 2*, 3*, 4* | 3*, 3*, 3* | 3, 3, 3 | 9, 8, 8 |
| H20V | 6, 6, 6 | 3, 4, 4 | 3*, 3*, 4* | 4, 5, 4 | 7, 8, 8 |
| H20W | 7, 7, 7 | 4, 4, 4 | 5, 4, 4 | 5, 5, 4 | 8, 8, 7 |
| H20Y | 6, 6, 6 | 3, 3, 4 | 4, 4, 3 | 4, 4, 4 | 6, 7, 7 |
Chromosomal indicates the wild-type strain W3110 carrying the vector plasmid pKP477. ΔtonB indicates strain KP1353 [tonB aroB exbB(A39E)] which served as the background in which all plasmids were analyzed. Wild-type TonB from pKP325 and TonB substitutions were expressed at chromosomal levels using the l-arabinose levels shown in Table 1.
Colicins were spotted in 5-fold dilutions in λ-Ca2+ buffer, and bacteriophage φ80 was spotted in 10-fold dilutions in λ-Ca2+ buffer. Results of triplicate assays for the highest dilution at which clearing was observed are shown. T, tolerance (insensitivity) to the agent tested; *, clearing was faint at all dilutions. A result of 0 indicates clearing was seen only with undiluted agent.