Skip to main content
×
Home
    • Aa
    • Aa

Photosystem II: the engine of life

  • James Barber (a1)
Abstract

1. Introduction 71

2. Electron transfer in PS II 72

3. (Mn)4cluster and mechanism of water oxidation 73

4. Organization and structure of the protein subunits 75

5. Organization of chlorophylls and redox active cofactors 81

6. Implications arising from the structural models 82

7. Perspectives 84

8. Acknowledgements 86

9. Addendum 86

10. References 87

Photosystem II (PS II) is a multisubunit membrane protein complex, which uses light energy to oxidize water and reduce plastoquinone. High-resolution electron cryomicroscopy and X-ray crystallography are revealing the structure of this important molecular machine. Both approaches have contributed to our understanding of the organization of the transmembrane helices of higher plant and cyanobacterial PS II and both indicate that PS II normally functions as a dimer. However the high-resolution electron density maps derived from X-ray crystallography currently at 3·7/3·8 Å, have allowed assignments to be made to the redox active cofactors involved in the light-driven water–plastoquinone oxidoreductase activity and to the chlorophyll molecules that absorb and transfer energy to the reaction centre. In particular the X-ray work has identified density that can accommodate the four manganese atoms which catalyse the water-oxidation process. The Mn cluster is located at the lumenal surface of the D1 protein and approximately 7 Å from the redox active tyrosine residue (YZ) which acts an electron/proton transfer link to the primary oxidant P680.+. The lower resolution electron microscopy studies, however, are providing structural models of larger PS II supercomplexes that are ideal frameworks in which to incorporate the X-ray derived structures.

Copyright
Corresponding author
Tel.: 44 2075945266; Fax: 44 2075945267; E-mail: j.barber@ic.ac.uk
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Quarterly Reviews of Biophysics
  • ISSN: 0033-5835
  • EISSN: 1469-8994
  • URL: /core/journals/quarterly-reviews-of-biophysics
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 74 *
Loading metrics...

Abstract views

Total abstract views: 280 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 18th August 2017. This data will be updated every 24 hours.