Table 4.
Steady-state cyt bc1 activities in various R. capsulatus cyt b Lys329 mutants
| Strains | Ps growth on enriched medium | DBH2 activity (%) | DBH2 activity (%) + Ant |
|---|---|---|---|
| MT-RBC1 | - | 1.9 ± 0.74 | ND |
| MT-RBC1/pMTSI (wild type) | + | 100.0 ± 4.9 | 13.5 ± 1.0 |
| MT-RBC1/pBK23 (Lys329Arg) | + | 85.0 ± 8.0 | 11.8 ± 1.3 |
| MT-RBC1/pBK30 (Lys329Ala) | - | 33.0 ± 5.3 | 7.2 ± 0.8 |
| MT-RBC1/pBK29 (Lys329Asp) | - | 10.7 ± 0.7 | 6.2 |
Ps growth refers to photosynthetic growth, and + or - indicates growth or no growth ability. DBH2 activity is indicated as a % of wild type (wt) cyt bc1 activity in R. capsulatus membranes. In this case, the 100 % of wild type activity corresponded to 1.19 μmoles of cyt c reduced/min/mg of total membrane proteins. The 1.9 % of wild type activity seen in MT-RBC1 lacking cyt bc1 corresponds to a cyt bc1-independent background activity. Ant, Antimycin A. ND, not determined. The fraction, if any, of residual antimycin-insensitive activities correspond to superoxide production was not determined.