Determination of Proton Transfer Rates by Chemical Rescue: Application to Bacterial Reaction Centers

The bacterial reaction center (RC) converts light into chemical energy through the reduction of an internal quinone molecule QB to QBH2. In the native RC, proton transfer is coupled to electron transfer and is not rate-controlling. Consequently, proton transfer is not directly observable, and its rate was unknown. In this work, we present a method for making proton transfer rate-controlling, which enabled us to determine its rate. The imidazole...