Elucidating the structure of the Mn4/Ca cluster and its mechanism for water oxidation in photosystem II (PSII) remains one of the most challenging problems in bio-energetics. While the most recent 1.9 A resolution crystal structure of PSII was a major advance, revealing for the first time the geometry of the Mn4/Ca cluster, its validity has been questioned because it exhibits anomalous features in conflict with earlier studies.
展开▼
