Progress Toward a Molecular Mechanism of Water Oxidation in Photosystem II

Annu Rev Phys Chem. 2017 May 5:68:101-116. doi: 10.1146/annurev-physchem-052516-044820. Epub 2017 Feb 2.

Abstract

The active site of photosynthetic water oxidation is the oxygen-evolving complex (OEC) in the photosystem II (PSII) reaction center. The OEC is a Mn4CaO5 cluster embedded in the PSII protein matrix, and it cycles through redox intermediates known as Si states (i = 0-4). Significant progress has been made in understanding the inorganic and physical chemistry of states S0-S3 through experiment and theory. The chemical steps from S3 to S0 are more poorly understood, however, because the identity of the substrate water molecules and the mechanism of O-O bond formation are not well established. In this review, we highlight both the consensuses and the remaining challenges of PSII research.

Keywords: oxygen evolution; photosynthesis; solar fuels.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Kinetics
  • Models, Molecular
  • Oxidation-Reduction
  • Oxygen / metabolism
  • Photosynthesis*
  • Photosystem II Protein Complex / chemistry
  • Photosystem II Protein Complex / metabolism*
  • Plants / chemistry
  • Plants / metabolism*
  • Protons
  • Water / metabolism*

Substances

  • Photosystem II Protein Complex
  • Protons
  • Water
  • Oxygen