Kinetics of phyllosemiquinone oxidation in the Photosystem i reaction centre of Acaryochloris marina

Stefano Santabarbara, Benjamin Bailleul, Kevin Redding, James Barber, Fabrice Rappaport, Alison Telfer

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

Light-induced electron transfer reactions in the chlorophyll a/d-binding Photosystem I reaction centre of Acaryochloris marina were investigated in whole cells by pump-probe optical spectroscopy with a temporal resolution of ~ 5 ns at room temperature. It is shown that phyllosemiquinone, the secondary electron transfer acceptor anion, is oxidised with bi-phasic kinetics characterised by lifetimes of 88 ± 6 ns and 345 ± 10 ns. These lifetimes, particularly the former, are significantly slower than those reported for chlorophyll a-binding Photosystem I, which typically range in the 5-30 ns and 200-300 ns intervals. The possible mechanism of electron transfer reactions in the chlorophyll a/d-binding Photosystem I and the slower oxidation kinetics of the secondary acceptors are discussed.

Original languageEnglish (US)
Pages (from-to)328-335
Number of pages8
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1817
Issue number2
DOIs
StatePublished - Feb 1 2012

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Keywords

  • Acaryochloris marina
  • Bidirectional electron transfer
  • Chlorophyll d
  • Photosystem I
  • Phylloquinone
  • Radical pair

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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