Proteins give lessons in water splitting

An international team of researchers has taken a significant step on the road to using water as a cheap source of hydrogen.

The researchers, from Imperial College London, UK, and from the Japan Science and Technology Corporation, used X-ray crystallography to study a protein complex called Photosystem II (PSII), which catalyses photosynthesis in plants and bacteria.

They studied the oxygen-evolving centre (OEC) of PSII in a cyanobacterium, Thermosynechococcus elongatus. They found that the OEC has a Mn₃CaO₄ cube-like structure, while a fourth reactive manganese atom links to one of the oxygen atoms of the cube. The researchers suggest that the structure gives strong hints about the way that amino acids and cofactors are involved in the water-splitting chemistry within photosynthesis.

’Manufacturing hydrogen from water using the photosynthetic method would be far more efficient than using electrolysis and if we can learn to use even a fraction of the 326m cubic miles of water on the planet we can begin to address the world’s pressing need for new and environmentally friendly energy sources,’ notes James Barber, who led the Imperial team.

Hamish Kidd