EPR studies of manganese spin centers in the even-number oxidation states of water oxidizing complex in photosystem II

To investigate the position of the spin center of the manganese clusters in water oxidizing complex in photosystem II (PS II), S-0-, S-2-, and S-2-states EPR signals were investigated of the preparations of each Si-state. The distances between the spin centers in the S0- and S-2- state multiline and Y-D radical have been determined by simulation of the time profiles of pulsed ELDOR in the biochemically reduced spinach PS II. These are 34.0 +/- 0.5 Angstrom and 33.0 +/- 1.0 Angstrom, for the S-0- and S-2-state, respectively. The distance for the S-2-state was obtained to be 27.0 +/- 0.5 Angstrom. in the 200 K illuminated PS II. The distances in the S-0- and S-2-states were same as those of a cyanobacterial photosystem II prepared by flash light illumination.