James Barber elucidated the mechanism of the first stage of photosynthesis, which enables plants to use the Sun’s energy to split water into oxygen and hydrogen, harvesting electrons. His insights into the structure and function of the key enzyme have since been applied in efforts to develop new sources of renewable energy.

Focusing on photosystem II, the multi-subunit protein complex that catalyses the splitting of water in green plants, algae and cyanobacteria, James undertook structural studies at ever-higher resolutions. These have revealed the three-dimensional arrangement of the metal-containing cluster at the centre of the catalytic site.

James instigated a programme to develop an ‘artificial leaf’ — based partly on studies of biological catalysts such as photosystem II — that could harness the abundant energy of the Sun to generate energy and capture atmospheric carbon dioxide. He was a winner of the Biochemical Society’s Novartis prize, and the Royal Society of Chemistry’s Interdisciplinary Prize.

Professor James Barber FRS died on 5 January 2020.