TABLE 1.
Oxidative phosphorylation in vivo and ATP synthesis activities in vitro
Oxidative phosphorylation in vivo and ATP synthesis activities of membrane preparations of mutants and controls were measured as described under “Materials and Methods.” When indicated, 20 μg/ml oligomycin was present in the ATP synthesis assay. The given values represent the average of at least four independent measurements ± S.D. The positive control was strain pTR19-ASDS/DK8, which expresses Bacillus PS3 ATP synthase in E. coli; this strain served as background for the deletions. The negative control was strain pUC118/DK8, which expresses neither PS3 ATP synthase nor the endogenous E. coli enzyme. The amount of F1Fo in the membrane preparations was measured by quantitative immunoblot analysis, as described under “Materials and Methods.” Turnover rates were calculated using a molecular mass of 531 kDa for the holoenzyme, taking into account the differing amounts of ATP synthase in the individual membrane preparations.
| Strain/mutation | Growth yields in limiting glucose | Amount of F1Fo on membranes | NADH-driven ATP synthesis ctivity | Turnover rate kcat |
|---|---|---|---|---|
| % of wild-type | % of total protein | milliunits/mg | s−1 | |
| Wild-type | 100 ± 4 | 20 ± 5 | 60 ± 22 | 2.7 |
| + oligomycin | 1.35 ± 0.50 | <0.1 | ||
| ϵI88stop | 101 ± 4 | 21 ± 6 | 151 ± 33 | 6.4 |
| Δγ | 65 ± 2 | 9 ± 4 | 0.62 ± 0.97 | <0.1 |
| pUC118/DK8 (unc−) | 65 ± 3 | 0 | 0.17 ± 0.85 | |
| γQ36stop | 75 ± 2 | 9 ± 2 | 7.5 ± 2.6 | 0.7 |
| + oligomycin | 0.13 ± 0.93 | <0.1 | ||
| γQ36stop/ϵI88stop | 62 ± 2 | 10 ± 2 | 1.03 ± 0.86 | <0.1 |
| γP43stop | 76 ± 3 | 13 ± 4 | 14.1 ± 3.4 | 1.0 |
| + oligomycin | −1.05 ± 1.26 | <0.1 | ||
| γP43stop/ϵI88stop | 71 ± 2 | 12 ± 4 | 9.5 ± 4.5 | 0.7 |
| + oligomycin | 0.04 ± 0.90 | <0.1 |