Tuning electron transfer by ester-group of chlorophylls in bacterial photosynthetic reaction center

Accessory chlorophylls (BA/B) in bacterial photosynthetic reaction center play a key role in charge-separation. Although light-exposed and dark-adapted bRC crystal structures are virtually identical, the calculated BA redox potentials for one-electron reduction differ. This can be traced back to different orientations of the BA ester-group. This tuning ability of chlorophyll redox potentials modulates the electron transfer from SP* to BA.