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Structural organization in photosynthetic proteins as studied by high‐field EPR of spin‐correlated radical pair states
Author(s) -
Link Gerhard,
Poluektov Oleg G.,
Utschig Lisa M.,
Lalevée Jacques,
Yago Tomoaki,
Weidner JoergUlrich,
Thurnauer Marion C.,
Kothe Gerd
Publication year - 2005
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1678
Subject(s) - electron paramagnetic resonance , chemistry , p700 , photosynthesis , photosystem i , pulsed epr , electron transfer , photosystem ii , site directed spin labeling , photosynthetic reaction centre , spectroscopy , chemical physics , photochemistry , nuclear magnetic resonance , spin echo , physics , biochemistry , medicine , quantum mechanics , magnetic resonance imaging , radiology
We demonstrate the potential of high‐field (HF) time‐resolved electron paramagnetic resonance (EPR) spectroscopy to reveal unique information about electron transfer processes and the structure of photosynthetic systems. The lineshapes and electron spin polarization (ESP) of spin‐correlated radical pair (SCRP) spectra recorded with HF‐EPR are very sensitive to the magnetic parameters, interactions, and geometry of the radicals in the pair. This sensitivity facilitates an analysis of more sophisticated models and methods to reveal the important relationship between structural organization and light‐induced electron transfer of the photosynthetic proteins. In this review, we report on a new time‐resolved HF and multi‐frequency EPR approach developed in the Freiburg laboratory in cooperation with the Argonne Photosynthesis group. The method is designed to probe the geometric structure of charge separated states in the photosynthetic membrane. First, we discuss the magneto‐orientation of photosynthetic cyanobacteria as revealed by time‐resolved HF‐EPR of SCRPs. Then, we demonstrate how the three‐dimensional structure of the SCRP $P_{700}^{+} A_{1}^{-}$ from photosystem I of oxygenic photosynthesis and its arrangement in the membrane is obtained from application of multi‐frequency including time‐resolved HF‐EPR techniques. Copyright © 2005 John Wiley & Sons, Ltd.