The distances from tyrosine D to redox-active components on the donor side of Photosystem II determined by pulsed electron-electron double resonance

AbstractA pulsed electron-electron double resonance (ELDOR) method was applied to measyre the dipole interactions between paramagnetic species on the donor side of Photosystem II. The distance between the Mn cluster and the redox-active tyrosine residue YD was determined to be 27 ± 0.2 Å in the S2 state of the oxygen-evolving Photosystem II. In Ca2+-depleted preparations the same distance was obtained from the measurement of the modified multiline signal. The distance between YD and the paramagnetic species giving rise to the split S3 signal was found to be 30 ± 0.2Å