Imperial College London

Professor Bill Rutherford FRS

Faculty of Natural SciencesDepartment of Life Sciences

Chair in Biochemistry of Solar Energy



+44 (0)20 7594 5329a.rutherford Website




702Sir Ernst Chain BuildingSouth Kensington Campus






BibTex format

author = {Zimmermann, JL and Rutherford, AW},
doi = {10.1016/0005-2728(84)90091-4},
journal = {BBA - Bioenergetics},
pages = {160--167},
title = {EPR studies of the oxygen-evolving enzyme of Photosystem II},
url = {},
volume = {767},
year = {1984}

RIS format (EndNote, RefMan)

AB - The light-induced EPR multiline signal is studied in O2-evolving PS II membranes. The following results are reported: (1) Its amplitude is shown to oscillate with a period of 4, with respect to the number of flashes given at room temperature (maxima on the first and fifth flashes). (2) Glycerol enhances the signal intensity. This effect is shown to come from changes in relaxation properties rather than an increase in spin concentration. (3) Deactivation experiments clearly indicate an association with the S2 state of the water-oxidizing enzyme. A signal at g = 4.1 with a linewidth of 360 G is also reported and it is suggested that this arises from an intermediate donor between the S states and the reaction centre. This suggestion is based on the following observations: (1) The g = 4.1 signal is formed by illumination at 200 K and not by flash excitation at room temperature, suggesting that it arises from an intermediate unstable under physiological conditions. (2) The formation of the g = 4.1 signal at 200 K does not occur in the presence of DCMU, indicating that more than one turnover is required for its maximum formation. (3) The g = 4.1 signal decreases in the dark at 220 K probably by recombination with Q-AFe. This recombination occurs before the multiline signal decreases, indicating that the g = 4.1 species is less stable than S2. (4) At short times, the decay of the g = 4.1 signal corresponds with a slight increase in the multiline S2 signal, suggesting that the loss of the g = 4.1 signal results in the disappearance of a magnetic interaction which diminishes the multiline signal intensity. (5) Tris-washed PS II membranes illuminated at 200 K do not exhibit the signal. © 1984.
AU - Zimmermann,JL
AU - Rutherford,AW
DO - 10.1016/0005-2728(84)90091-4
EP - 167
PY - 1984///
SN - 0005-2728
SP - 160
TI - EPR studies of the oxygen-evolving enzyme of Photosystem II
T2 - BBA - Bioenergetics
UR -
VL - 767
ER -