title: Recent developments in research on water oxidation by photosystem II.
abstract: Photosynthetic water oxidation chemistry at the unique manganese-calcium complex of photosystem II (PSII) is of fundamental importance and serves as a paragon in the development of efficient synthetic catalysts. A recent crystal structure of PSII shows the atoms of the water-oxidizing complex; its Mn4CaO5 core resembles inorganic manganese-calcium oxides. Merging of crystallographic and spectroscopic information reverses radiation-induced modifications at the Mn-complex in silico and facilitates discussion of the O-O bond chemistry. Coordinated proton movements are promoted by a water network connecting the Mn4CaO5 core with the oxidant, a tyrosine radical and one possibly mobile chloride ion. A basic reaction-cycle model predicts an alternating proton and electron removal from the catalytic site, which facilitates energetically efficient water oxidation.
authors.affiliation: Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany. holger.dau@fu-berlin.de
authors.forename: Holger
authors.initials: H
authors.lastname: Dau
authors.forename: Ivelina
authors.initials: I
authors.lastname: Zaharieva
authors.forename: Michael
authors.initials: M
authors.lastname: Haumann
mesh_terms: D006860:Hydrogen Bonding; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D014867:Water / Q000378:metabolism*
chemical_list: D045332:Photosystem II Protein Complex; D014867:Water