Speaker
Dr
Pieter Glatzel
(ESRF)
Description
The oxygen-evolving complex (OEC) located in the PSII membrane-bound protein in plant, algae, and cyanobacteria catalyses the water-oxidation reaction. The OEC, with four Mn and one Ca, couples the 4-electron chemistry of water oxidation with the one-electron photochemistry of the reaction center by sequentially storing oxidizing equivalents through five intermediate S-states (Si, i = 0 to 4), before one molecule of dioxygen is evolved. The Mn4CaO5 cluster provides a high degree of redox and chemical flexibility so that several oxidizing equivalents can be stored during the S-state cycle. To understand the mechanism of water oxidation in detail, it is crucial to know how the electronic and geometric structure of Mn4CaO5 changes during the catalysis and how the nature of the Mn-oxo bridges is affected by that. The S-states can be isolated by rapid freeze-quench after illumination but ideally the experiments are performed in a time-resolved manner at room temperature with in-situ illumination.
Primary author
Dr
Pieter Glatzel
(ESRF)
