Current molecular mechanisms of photosynthetic oxygen evolution

The recently published 3.5-angstrom resolution X-ray crystal structure of a cyanobacterial Photosystem II provides a detailed architecture of the oxygen-evolving complex (OEC) and the surrounding amino acids. Despite intense interest in the mechanism of dioxygen evolution by the OEC of Photosystem II in green plants, the precise mechanism involved remains a matter of debate. In this paper two mechanisms are compared, and a new mechanism is described.