The study describes the coordinated changes that must occur in the protein to facilitate the reaction and shows that the strength of the hydrogen-bonded network is important.
"This research helps to clarify how ammonia inhibits the photosystem, which is something that researchers have been wondering about for many years," Barry explained. "Our work suggests that ammonia can inhibit the reaction by disrupting this network of hydrogen bonds."
The research also suggests that in design of artificial devices that carry out this reaction, sustaining a similar hydrogen-bonding network may be important. The stabilizing effect of trehalose discovered by Polander and Barry may also be important.
Beyond the importance of understanding the photosynthetic process, the work could lead to new techniques for producing hydrogen and oxygen using sunlight. One possibility would be to add a biomimetic photocatalytic process to a photovoltaic system producing electricity from the sun.
"In terms of providing new sources of energy, we still have lessons to learn from plants about how they carry out these critical processes," Barry said. "It would be a great advance for the planet to have new, sustainable, and inexpensive processes to carry out this reaction."
Ultimately, she hopes the full water oxidizing cycle can be explored and potentially harnessed or imitated for oxygen and energy production.
"We are only looking at a single part of the overall reaction now, but we would like to study the entire cycle, in which oxygen is produced, to see how the interactions in the water network change and how the interactions with the protein change," Barry said. "The work is another step in understanding how plants carry out this amazing series of photosynthetic reactions."
|Contact: John Toon|
Georgia Institute of Technology Research News