Quinone (Q_B) Reduction by B-Branch Electron Transfer in Mutant Bacterial Reaction Centers fromRhodobacter sphaeroides: Quantum Efficiency and X-ray Structure^,

The photosynthetic reaction center (RC) from purple bacteria converts light into chemical energy. Although the RC shows two nearly structurally symmetric branches, A and B, light-induced electron transfer in the native RC occurs almost exclusively along the A-branch to a primary quinone electron acceptor QA. Subsequent electron and proton transfer to a mobile quinone molecule QB converts it to a quinol, QBH2. We report the construction and...