Tempe, Ariz. - An international team of scientists, including two from Arizona State University, have taken a significant step closer to unlocking the secrets of photosynthesis, and possibly to cleaner fuels.
Plants and algae, as well as cyanobacteria, use photosynthesis to produce oxygen and "fuels," the latter being oxidizable substances like carbohydrates and hydrogen. There are two pigment-protein complexes that orchestrate the primary reactions of light in oxygenic photosynthesis: photosystem I (PSI) and photosystem II (PSII). Understanding how these photosystems work their magic is one of the long-sought goals of biochemistry.
The ASU scientists working with collaborators at the Max Planck Institute at Mlheim a.d. Ruhr in Germany have been investigating the PSI reaction center.
They have made an important observation that is nut-shelled in the title of a paper published in this week's online Early Edition of the Proceedings of the National Academy of Sciences (PNAS). The paper is titled "Independent initiation of primary electron transfer in the two branches of the photosystem I reaction center."
Kevin Redding, an associate professor in the department of chemistry and biochemistry in the College of Liberal Arts and Sciences, is leading the research at ASU. His lab created mutations in a single-celled green alga (Chlamydomonas reinhardtii or 'Chlamy' for short). Using these mutants, Redding and collaborators have shown that the primary light-triggered electron transfer event in the PSI reaction center can be initiated independently in each of its parallel branches. At the same time, they showed that PSI has two charge separation devices that effectively work in parallel to increase the overall efficiency of electron transfer.
"Although we knew that both branches were being used in PSI, and that our mutations had an effect upon the relative use of each pathway, what we did not know was how these mutatio
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Arizona State University