Table 3. Assignment of the reduction potential of each cluster in PqqE and its variants.
The reported reduction potentials of other SPASM/twitch domain proteins are listed for comparison. Uncertainties of the experimental redox potentials are ± 3 mV for the single cluster variants, and ± 5 mV for the other variants.
| Reduction potential (mV vs. S. H. E.) | |||
|---|---|---|---|
| PqqE variants | (RS [4Fe-4S]) | (AuxI [2Fe-2S]) | (AuxII [4Fe-4S]) |
| WT | −485 | −435 | −535 |
| AuxI/AuxII | - | −440 | −510 |
| RS/AuxII | −460 | - | −525 |
| RS/AuxI | −495 | −435 | - |
| RS only | −455 | - | - |
| AuxI only | - | −370 | - |
| RS/AuxI/D319H | −465 | −405 | −520 |
| RS/AuxI/D319C | −500 | −445 | −555 |
| RS/D319C | −440 | - | −495 |
| AuxI/D319C | - | −500 | −560 |
| RS/C268H/AuxII | −475 | - | −520 |
| Other SPASM/twitch | E1 | E2 | E3 |