TABLE 1.
Cell growth and activities of both ribosomal subunits and reconstituted particles of the strains dnaK+ (MC41.14) and ΔdnaK (BB11)
| MC 41.14 dnaK+ | BB11 ΔdnaK52::cmR | ||
|---|---|---|---|
| aDistinctive phenotypes of the dnaK+ and ΔdnaK strains used for in vitro reconstitution studies. | |||
| bPoly(Phe) synthesis activity of subunits derived from both dnaK+ and ΔdnaK strains in the presence of an excess of the complementary native subunits from the strain CAN20-12E (dnaK+). For details, see Materials and Methods. | |||
| c30S reconstitution experiments were performed with TP30 and 16S rRNA from both strains (dnaK+ and ΔdnaK) in all possible combinations. The activity of the reconstituted particles was assessed by poly(Phe) synthesis in the presence of an excess of native 50S subunits from strain CAN20-12E (dnaK+). | |||
| dExperiments corresponding to those described in C but involving 50S reconstituted particles. Background values (no reconstituted particles) between 150 and 500 cpm were subtracted. The resulting Phe incorporation values were between 7200 and 21,000 cpm, corresponding to 35 and 105 Phe incorporated per 70S ribosome, respectively. | |||
| A. Phenotypea | |||
| Growth at 30°C | + | + | |
| Growth at 30°C + 25 μg/mL chloramphenicol | − | + | |
| Growth at 37°C | + | − | |
| B. Ribosome activity (Phe incorporation per 70S)b | |||
| 50S subunits (in the presence of wt30S) | 88 ± 4 | 80 ± 5 | |
| 30S subunits (in the presence of wt50S) | 105 ± 5 | 103 ± 4 | |
| C. Reconstituted 30S subunits (Phe incorporation per 70S) (in the presence of native 50S)c | |||
| TP30 | |||
| dnaK+ | ΔdnaK | ||
| 16S rRNA | dnaK+ | 40 ± 3 | 36 ± 2 |
| ΔdnaK | 47 ± 3 | 48 ± 2 | |
| D. Reconstituted 50S subunits (Phe incorporation per 70S) (in the presence of native 30S)d | |||
| TP50 | |||
| dnaK+ | ΔdnaK | ||
| (23S + 5S) rRNA | dnaK+ | 48 ± 3 | 49 ± 3 |
| ΔdnaK | 46 ± 2 | 42 ± 3 | |
