Mark Paddock, Ph.D University of California, San Diego

Proton Transfer within the Bacterial Reaction Center

My initial experimental investigations have included determining the primary pathway for proton transfer into the catalytic Q_B site and investigations on the coupling of proton and electron transfer reactions that occur in the conversion of quinone to dihydroquione:

Q_B + 2e^- + 2H⁺ + 2hν → Q_BH₂
The reaction occurs in two sequential electron transfer steps followed by internal proton transfer (at physiological pH values). Protons are transferred from the external aqueous solvent through amino acid side chains and bound water molecules to the reduced quinone within the Q_B sites (see Figure). (More details are available in the publication list.)