Achievement

Trainee K. Nguyen along with Task 1 faculty Drs. Bruce and Frymier have been studying how to increase the reduction of photosystem I primary electron donor (P700+) by the soluble electron carrier, cyt c6. Using a LED pump-probe spectrometer, we have generated a detailed in vitro profile of the re-reduction kinetics. We can also vary the kinetics of this process by nearly 1000-fold by modulating factors including cyt c6 concentration, temperature, pH, and ionic strength. In addition to these factors, we have also used comparative genomics and structural biology to explore the surface properties of these proteins that influence their interaction. Taking a lesson from higher plants and algae, we have been mimicking electrostatic interactions between PSI and cyt c6. By increasing the binding kinetics of this electron donor-acceptor (cyt-PSI) interaction, we predict a parallel increase in H2 evolution rate with a bound hydrogenase to PSI.