Non-damaging X-ray technique unveils protein complex uses sunlight split water

Non-damaging X-ray technique unveils protein complex that uses sunlight to split water

8:16 AM, 7th February 2015
Non-damaging X-ray technique unveils protein complex that uses sunlight to split water
The molecular architecture of the photosynthetic oxygen-evolving complex (gray: manganese, blue: calcium, red and yellow: oxygen, orange: water.

SAITAMA, JAPAN: A non-damaging X-ray technique improves our understanding of the protein complex that uses sunlight to split water. According to study by researchers from the RIKEN SPring-8 Center, Okayama University and the Japan Science and Technology Agency, a more accurate view of the structure of the oxygen-evolving complex that splits water during photosynthesis is now in hand. The new model of natural photosynthesis provides a blueprint for synthesizing water-splitting catalysts that mimic this natural process.

Natural photosynthesis starts in an elaborate pigment–protein complex known as photosystem II, which is found in cellular membranes of higher plants, algae and cyanobacteria. This complex catalyzes the splitting of water into oxygen, hydrogen ions and electrons. In principle, this reaction is a solar-powered fuel cycle, with the only end product being the water formed when the hydrogen and oxygen are recombined to release energy.

“The bottleneck in producing sustainable and clean fuel energy from sunlight and water is the availability of efficient artificial catalysts for water splitting,” said Hideo Ago from the RIKEN research team. This explains why there is such intense interest in understanding exactly how nature splits water so efficiently.

The structure of photosystem II has been examined before at very high resolution by x-ray diffraction crystallography, and detailed models of the system have been obtained. However, the high-energy x-rays used in such analyses tend to damage the structure of the complex, resulting in some discrepancy among findings and a lack of clarity for certain atomic structures.

The research team avoided the problem of radiation damage by using a series of ultrashort femtosecond x-ray pulses generated by RIKEN’s ‘SACLA’ x-ray free-electron laser facility. The short pulses prevented structural damage and the more accurate results allowed the researchers to identify several new features of the catalytic center of photosystem II from the bacterium Thermosynechococcus vulcanus. The results indicate that catalysis occurs in a cluster of manganese and oxygen atoms with one calcium atom. With more accurate measurement of the distances between the atoms, the researchers revealed that one of the oxygen atoms may actually form part of a hydroxide ion and could be derived from a split water molecule.

“We solved the structure in the ‘dark-stable’ state before the water-splitting reaction. We now hope to use the same method with light illumination to follow the process through the reaction cycle,” explained Jian-Ren Shen, one of the researchers from Okayama University. Such a study would provide a complete picture of how the biological photosynthesis reaction proceeds and greatly assist efforts to use the process in a fuel cycle.

 

© RIKEN News 

0 Comments

Login

Your Comments (Up to 2000 characters)
Please respect our community and the integrity of its participants. WOC reserves the right to moderate and approve your comment.

Related News


Technip bags ethylbenzene and styrene monomer plant contract in China

SHANGHAI, CHINA: Technip has been awarded by Qingdao Soda Ash Industrial & New Material Technology Company a contract for the supply of technology ...

Read more
Tronox to acquire FMC’s alkali chemicals business for $1.64 billion

STAMFORD, US: Tronox Limited has signed a definitive agreement with FMC Corporation to acquire its Alkali Chemicals business for $1.64 billion. The tr ...

Read more
Understanding ammonium carbonate monohydrate

CHESTER, UK: New structural studies of the superficially simple ammonium carbonate monohydrate could shed light on industrial processes, biochemistry ...

Read more
IFF opens new flavors facility in Chicago, US

NEW YORK, US: International Flavors & Fragrances Inc (IFF), a leading global creator of flavors and fragrances for consumer products, announced th ...

Read more
Transistors made of one-atom-thick silicon for super fast computing

AUSTIN, US: Researchers at The University of Texas at Austin’s Cockrell School of Engineering have created the first transistors made of silicen ...

Read more
Endocrine disrupting chemicals linked to early menopause, finds study

ST LOUIS, US: Fifteen chemicals that disrupt our endocrine hormonal systems have been linked to earlier menopause among US women. Amber Cooper from Wa ...

Read more
www.worldofchemicals.com uses cookies to ensure that we give you the best experience on our website. By using this site, you agree to our Privacy Policy and our Terms of Use. X