Table 1.
Summary of photoreduction (σr) and photooxidation (σo) cross-section determined from Fig. 4A
| Cross-section | Pa cyt c551 WT | Pa cyt c551 F7A | hh cyt c |
| σr (cm2) | 6.4 × 10−20 | 7.3 × 10−21 | 4.3 × 10−22 |
| σo (cm2) | 3.6 × 10−20 | 5.8 × 10−20 | 0.88 × 10−22 |
The photooxidation cross-sections are expected to be less sensitive to the ruffling distortion because photooxidation probably involves electron loss from the ferrous π* excited state. The ferrous iron is low-spin and already has fully filled iron t2g orbitals, so that there is no localized or delocalized hole state (associated with an unpaired iron d electron) available to modulate the tunnel distance.