T. Matsukawa et al., Electron paramagnetic resonance study of the magnetic structure of the S-1-state in oriented oxygen evolving photosystem II membranes, SPECT ACT A, 55(4), 1999, pp. 895-901
Citations number
29
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
The S-1-state of the oxygen evolving complex was studied in oriented photos
ystem II membranes by parallel polarization electron paramagnetic resonance
(EPR) spectroscopy. The EPR intensity, ascribed to the S-1-state Mn-cluste
r with S = 1, varies depending on the magnetic field direction relative to
the membrane normal: maximum and minimum were observed at angles of 0 and 9
0 degrees, respectively. Successful simulations of line shape and intensity
observed in the non-oriented and the oriented membranes were obtained usin
g the values of the zero-field parameter, D = +/- 0.14 +/- 0.01 cm(-1) and
E/D = - 0.11 +/- 0.02, by assuming an isotropic g-value of 2.0. The anisotr
opy in EPR intensity shows that the axial direction of the zero-field inter
action of the manganese cluster is almost parallel to the membrane plane. (
C) 1999 Elsevier Science B.V. All rights reserved.