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The Photosynthetic Mn Complex in Its Reaction Cycle: An Attempt to Obtain Pure FTIR Difference Spectra for the Four Transitions Between Semi-Stable S-States and for QB Redox Transitions

  • Björn Süss
  • Holger Dau
Conference paper

Abstract

In Oxygenic Photosynthesis, Water Is Oxidized At A Mn4Ca Complex Bound To The Proteins Of Photosystem Ii (Psii). The Water-Oxidation Cycle Of The Mn Complex May Involve Nine Distinct States Of The Mn Complex (Dau And Haumann 2006), But Only Four Of These Are Stable For Several Seconds (S2, S3), Several Hours (0), Or Fully Dark-Stable (S1). The Four Transitions Between These Semi-Stable S-States Have Been Studied By A Variety Of Spectroscopic Techniques. Due To The Pioneering Work Of Several Groups, Today Also Ftir Spectroscopy Plays A Prominent Role Frequently In Fruitful Conjunction With Mutagenesis Studies (See, E.G., Studies Of Debus And Coworkers). After Application Of Ns Or μS Flashes Of Saturating Light And Subsequent Ftir Measurements, Difference Spectra Can Be Calculated Which Are Mostly Interpreted As S-State Difference Spectra. However, Potential Complications Come From (I) Acceptor Side Contributions To The Ftir Spectra, (Ii) Psii With A Partially Defect Donorside, And (Iii) Significant Mixing Of S-State Populations Caused By So-Called Miss Events. We Have Measured Ftir Spectra On Psii Membrane Particles In The Intervals Between Laser Flashes Of An Extended Flash Sequence. Taking Into Account Also Complementary Results Obtained By Time-Resolved Prompt And Delayed Fluorescence Measurements, We Attempt A Correction (Or Deconvolution) For (I) To (Iii). These Investigations Aim At A Rationale To Get The Pure S-State Difference Spectra In Ftir Investigations On The Reaction Cycle Of Psii Water Oxidation. First Results Are Presented; Problems And Perspectives Are Discussed.

Keywords

Photosystem II FTIR S-state transitions 

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References

  1. Dau H, Haumann M (2006) Reaction cycle of photosynthetic water oxidation. Science 312: 1471-1472 (letter section).Google Scholar
  2. Dau H, Haumann M (2007) Time-resolved X-ray spectros-copy leads to an extension of the classical S-state cycle model of photosynthetic oxygen evolution. Photosynth Res Photosynth Res 92:327-343.CrossRefGoogle Scholar
  3. Debus RJ, Strickler MA, Walker LM, Hillier W (2005) No evidence from FTIR difference spectroscopy that aspartate-170 of the D1 polypeptide ligates a manga-nese ion that undergoes oxidation during the S0 to S1, S1 to S2, or S2 to S3 transitions in photosystem II. Biochemistry 44:1367-1374.PubMedCrossRefGoogle Scholar
  4. Kok B, Forbush B, McGloin M (1970) Cooperation of charges in photosynthetic O2 evolution - I. A linear four-step mechanism. Photochem Photobiol 11:457-475.PubMedCrossRefGoogle Scholar
  5. Noguchi T, Sugiura M (2002) Flash-induced FTIR differ-ence spectra of the water oxidizing complex in mod- erately hydrated photosystem II core films: Effect of hydration extent on S-state transitions. Biochemistry 41:2322-2330.PubMedCrossRefGoogle Scholar
  6. Yamanari T, Kimura Y, Mizusawa N, Ishii A, Ono T-A (2004) Mid- to low-frequency fourier transform infra-red spectra of S-state cycle for photosynthetic water oxidation in Synechocystis sp. PCC 6803. Biochemistry 43:7479-7490.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science + Business Media, B.V. 2008

Authors and Affiliations

  • Björn Süss
    • 1
  • Holger Dau
    • 1
  1. 1.Freie Universität Berlin, FB PhysikBerlinGermany

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