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Updated: Jul 31, 2026

Electron Spin Resonance Micro-imaging of Live Species for Oxygen Mapping
Published on: August 27, 2010
Light-induced structural changes in photosynthetic reaction centres studied by ESEEM of spin-correlated D+QA- radical
I V Borovykh1, S A Dzuba, I I Proskuryakov
1Department of Biophysics, Huygens Laboratory, Leiden University, P.O. Box 9504, 2300 RA Leiden, Netherlands.
Abstract:
Zn-substituted Rhodobacter sphaeroides R26 reaction centres (RCs) frozen in the dark and under illumination exhibit quite different recombination kinetics of the D+QA- radical pairs [Kleinfeld et al., Biochemistry, 23 (1984) 5780]. We have applied electron spin echo envelope modulation (ESEEM) of the spin-correlated D+QA- radical pairs to assess a possible light-induced change in the distance between the D and QA cofactors. The recombination kinetics and the field-swept spin-polarized EPR signal for the two preparations have been monitored by time-resolved EPR spectroscopy. For the samples frozen under illumination, a slight increase in the distance, 0.4+/-0.2 A, has been detected.
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