Protein-water-cofactor interactions in biological water oxidation - a paradigm for base metal activation

Photosynthesis by cyanobacteria, algae and plants is the basis for life on Earth as it converts solar into chemical energy and produces the oxygen we breadth.

These organisms perform the complex 4-electron 4-proton water oxidation chemistry by a metal-oxide cluster made of manganese and calcium, meanwhile artificial attempts to mimic this process require rare and expensive metals.

Recent progress has led to a deep understanding of the structure and function of the Mn4CaO5 cofactor and the process of O-O bond formation.

Similarly, insight starts to evolve regarding the structural dynamics of the photosystem II (PSII) complex and its water channels.

Nevertheless, the biological design principles leading to the high-activity and stability of the Mn4CaO5 cluster inside PSII have remained unknown beyond the general hypothesis that protein-water-cofactor interactions must be the decisive factor.

Our recent cryo-EM structure of PSII, with a record resolution of 1.71 Å, has opened the door towards an experimental identification H-atoms.

Here we propose to employ the complementary cryo-EM and XFEL techniques together with biophysical characterization and advanced QM/MM and MD multiscale simulations to unravel the function of protein-water-cofactor interactions in PSII.

We see this as an important step towards developing general design principles for base metal catalysts required for sustainable energy conversion reactions and green chemistry.