Photosynthesis Research

, Volume 92, Issue 3, pp 289–303

Oxidation state changes of the Mn4Ca cluster in Photosystem II

Authors

    • Melvin Calvin Laboratory, Physical Biosciences DivisionLawrence Berkeley National Laboratory
    • Melvin Calvin Laboratory, Physical Biosciences DivisionLawrence Berkeley National Laboratory
Research Article

DOI: 10.1007/s11120-007-9153-5

Cite this article as:
Yano, J. & Yachandra, V.K. Photosynth Res (2007) 92: 289. doi:10.1007/s11120-007-9153-5

Abstract

A detailed electronic structure of the Mn4Ca cluster is required before two key questions for understanding the mechanism of photosynthetic water oxidation can be addressed. They are whether all four oxidizing equivalents necessary to oxidize water to O2 accumulate on the four Mn ions of the oxygen-evolving complex, or do some ligand-centered oxidations take place before the formation and release of O2 during the S→ [S4] → S0 transition, and what are the oxidation state assignments for the Mn during S-state advancement. X-ray absorption and emission spectroscopy of Mn, including the newly introduced resonant inelastic X-ray scattering spectroscopy have been used to address these questions. The present state of understanding of the electronic structure and oxidation state changes of the Mn4Ca cluster in all the S-states, particularly in the S2 to S3 transition, derived from these techniques is described in this review.

Keywords

Photosystem IIWater oxidationOxygen evolutionManganese clusterX-ray spectroscopy

Abbreviations

PS II

Photosystem II

OEC

oxygen-evolving complex

EPR

electron paramagnetic resonance

ENDOR

Electron-Nuclear Double Resonance

XAS

X-ray absorption spectroscopy

EXAFS

extended X-ray absorption fine structure

XANES

X-ray absorption near-edge spectroscopy

MLS

multiline EPR signal

NIR

near infra-red

IPE

Inflection point energy

XES

X-ray emission spectroscopy

RIXS

resonant inelastic X-ray scattering

CIE

constant incident energy

CET

constant energy transfer

Copyright information

© Springer Science+Business Media B.V. 2007