During the remarkable cascade of events of photosynthesis, plants approach the pinnacle of stinginess by scavenging nearly every photon of available light energy to produce food. Yet after many years of careful research into its exact mechanisms, some key questions remain about this fundamental biological process that supports all life on earth.

Now, a large research team led by Neal Woodbury, a scientist at ASU's Biodesign Institute, has come up with a new insight into the mechanism of photosynthesis, which involves the orchestrated movement of proteins on the timescale of a millionth of a millionth of a second. Their findings are described in "Protein Dynamics Control the Kinetics of Initial Electron Transfer in Photosynthesis," in the May 4 issue of Science.

"The studies that led up to this work initiated 20 years ago when Jim Allen and I looked at one of our mutants and thought our spectrometer was broken," Woodbury said. "That mutant turned out to be the first of a long series of mutations that systematically altered the energy of the initial reaction." Since then, Woodbury and colleagues have managed to shed light on an amazing process that provides earth's primary power source.

To get a closer look at what was happening during photosynthesis, the team used a well studied purple photosynthetic bacterium called Rhodobacter sphaeroides. This type of organism was likely one of the earliest photosynthetic bacteria to evolve. The researchers focused their efforts by studying the center stage of photosynthesis, the reaction center, where light energy is funneled into specialized chlorophyll binding proteins.

The textbook picture of photosynthesis represents the reaction center proteins as a scaffold, holding chlorophyll molecules at a highly optimized distance and orientation so that electrons can hop from one chlorophyll to another. With the chlorophylls in just the right position, any systematic pr
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Contact: Joe Caspermeyer
joseph.caspermeyer@asu.edu
480-727-0369
Arizona State University
3-May-2007