X-ray spectroscopy of the photosynthetic oxygen-evolving complex

Water oxidation to dioxygen in photosynthesis is catalyzed by a Mn4Ca cluster with 0 bridging in Photosystem, II (PS II) of plants, algae and cyanobacteria. A variety of spectroscopic methods have been applied to analyzing the participation of the complex. X-ray spectroscopy is particularly useful because it is element- speci fi c, and because it can reveal important structural features of the complex with high accuracy and identify the participation of Mn in the redox chemistry. Following a brief history of the application of X-ray spectroscopy to PS II, an overview of newer results will be presented and a description of the present state of our knowledge based on this approach. (c) 2007 Elsevier B.V. All rights reserved.