TABLE 3.
Activity of TonB1-TonBEc chimeras in P. aeruginosa and E. coli
| Plasmid | TonB (sequences)a | Zone of growth (diam [cm])
|
Growth (OD600) of E. coli KP1032d | |
|---|---|---|---|---|
| P. aeruginosa K1040b | E. coli RK5015c | |||
| pQZ-06 | Wild type | 2.7 | 2.8 | 0.65 |
| pMMB206 | 0 | 0 | ||
| pQZ-CPa-1 | TonBEc (1-152)-TonB1 (254-342) | 2.6 | 3.2 | 0.66 |
| pQZ-CPa-2 | TonBEc (1-170)-TonB1 (272-342) | 0 | 0 | 0.00 |
| pQZ-CPa-3 | TonBEc (1-199)-TonB1 (301-342) | 0 | 0 | 0.00 |
| pQZ-CPa-4 | TonBEc (1-217)-TonB1 (319-342) | 0 | 0 | 0.00 |
| pQZ-NPa-1 | TonB1 (1-254)-TonBEc (154-239) | 0 | 2.2 | 0.59 |
| pQZ-NPa-2 | TonB1 (1-273)-TonBEc (173-239) | 0 | 2.8 | 0.76 |
| pQZ-NPa-3 | TonB1 (1-304)-TonBEc (204-239) | 0 | 2.8 | 0.73 |
| pQZ-NPa-4 | TonB1 (1-319)-TonBEc (219-239) | 0 | 0 | 0.79 |
| pQZ-CEc-1 | TonB1 (1-81)-TonBEc (1-239) | (1)e | 2.9 | 0.43 |
| pQZ-CEc-2 | TonB1 (1-140)-TonBEc (51-239) | 0 | 2.7 | 0.88 |
The positions of the corresponding amino acid sequences of TonB1 and TonBEc encoded by the chimeric tonB genes present on the indicated plasmids are indicated in parentheses.
The TonB1-deficient P. aeruginosa K1040 strain harboring wild-type tonB1 or the indicated tonB1-tonBEc plasmids were plated onto the surface of an iron-deficient succinate minimal plate containing 180 μg of EDDHA/ml and 20 μM IPTG (to induce the tonB genes). Filter disks impregnated with 8 μl of pyoverdine (50-mg/ml stock) were placed on the plates, and the zones of growth (i.e., diameter) appearing after ca. 40 h at 37°C were measured. The data are representative of three separate experiments.
The tonB metE mutant E. coli strain RK5015 harboring wild-type tonB1 or the indicated tonB1-tonBEc plasmids were plated onto the surface of glucose minimal plates containing 20μM IPTG. Filter disks impregnated with 8 μl of vitamin B12 (10 μM stock) were placed on the plates, and the zones of growth (i.e., diameter) appearing after ca. 40 h at 37°C were measured. The data are representative of three separate experiments.
The E. coli tonB mutant KP1032 carrying the indicated plasmids was inoculated into DTSB medium at an OD600 of 0.05, and growth (i.e., the increase in cell density as measured by OD600) was monitored for 10 h. The final OD600 at 10 h is shown above. The data are representative of three independent experiments and have been corrected for background growth (OD600 = 0.18) of KP1032 carrying pMMB206.
Weak growth.