Magnetic-field-induced orientation of photosynthetic reaction centers, as revealed by time-resolved d-band Electron Paramagnetic Resonance of Spin-correlated radical pairs. II. Field dependence of the alignement
| Autor: | Thomas Berthold, Eli Stavitski, Gerd Kothe, Jochen R. Golecki, Giorgio J. Moro, Sandra L. Schlesselman, Oleg Poluektov, Ulrich Heinen, Ernst Ohmes, and Marion C. Thurnauer, Haim Levanon |
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| Jazyk: | angličtina |
| Rok vydání: | 2004 |
| Předmět: |
Photosynthetic reaction centre
ORIENTATIONAL ORDER PARAMETERS Chemistry electron paramagnetic resonance photosynthetic reaction center Photosystem I Molecular physics Spectral line Surfaces Coatings and Films law.invention Magnetic field Nuclear magnetic resonance law Materials Chemistry Diamagnetism Physical and Theoretical Chemistry Electron paramagnetic resonance Anisotropy Spin (physics) |
| Popis: | The magnetic-field-induced orientation of photosynthetic reaction centers has been studied by time-resolved D-band (130 GHz) electron paramagnetic resonance (EPR) of the secondary radical pair, , in plant photosystem I (PSI). Experiments have been performed for fresh and lyophilized whole cells of the deuterated cyanobacterium S. lividus. A computer fit of the angle-dependent D-band spectra, measured for two different sample orientations, provides the order parameter SZ‘Z‘ of the symmetry axis, Z‘, of the susceptibility tensor, relative to the magnetic field. The positive sign of this order parameter indicates that membrane proteins are the major source for the anisotropy of the diamagnetic susceptibility, ΔχV. A value for ΔχV has been extracted from the magnetic-field dependence of SZ‘Z‘. The value of ΔχV = 5.7 × 10-27 m3 is in good agreement with an estimate for the susceptibility anisotropy of a cyanobacterial cell. This demonstrates that whole cells are aligned in the magneto-orientation process. The ... |
| Databáze: | OpenAIRE |
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