In a recent study published in Nature, a team of researchers examined a process known as Photosystem II, which is the protein complex that photosynthesis uses to harvest sunlight and convert carbon dioxide into energy, and ultimately oxygen. This study holds the potential to help scientists develop artificial photosynthetic systems that can eventually convert carbon dioxide into hydrogen and other carbon-based fuels.
Scientists have revealed the oxygen-producing that happens duirng photosynthesis using SLAC’s X-ray laser. (Credit: Greg Stewart/SLAC National Accelerator Laboratory)
“Photosystem II is giving us the blueprint for how to optimize our clean energy sources and avoid dead ends and dangerous side products that damage the system,” said Dr. Junko Yano, who is a scientist at Berkeley Lab and a co-author on the study. “What we once thought was just fundamental science could become a promising avenue to improving our energy technologies.”
For the study, the researchers used the Stanford Linear Accelerator Center (SLAC) Linac Coherent Light Source and the SPring-8 Angstrom Compact free electron LAser in Japan to reveal both the atomic structure and chemical processes of Photosystem II’s oxygen-evolving center, which is responsible for separating water molecules to release molecular oxygen. They were able to examine this center by using optical light to excite cyanobacteria samples then blasting them with rapid pulses of X-rays. Through this, the researchers were able to image what’s known as the transient state of Photosystem II where two oxygen atoms are bonded to form molecular oxygen, which is the first time this has been achieved.
“Other experts argued that this is something that could never be captured,” said Dr. Uwe Bergmann, who is professor at the University of Wisconsin-Madison, and a co-author on the study. “It’s really going to change the way we think about Photosystem II. Although we can't say we have a unique mechanism based on the data yet, we can exclude some models and ideas people have proposed over the last few decades. It’s the closest anyone has ever come to capturing this final step and showing how this process works with actual structural data.”
Photosynthesis is one of the key reasons why life on Earth exists and continues to thrive, which is why researchers like the ones who conducted this study are so eager to learn about its processes. Photosynthesis and its processes also hold applications for agriculture, environmental control, medicine, and electronics. The more we understand how photosynthesis works, the higher chance we have of saving life on Earth in a time when climate change is ravaging the planet more and more every day.
Going forward, the team hopes to image many more steps of this complicated, chemical process, which they plan to use with upgraded equipment.
What new discoveries will researchers make about photosynthesis and its applications in the coming years and decades? Only time will tell, and this is why we science!
As always, keep doing science & keep looking up!