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 = {Rutherford, AW},
doi = {10.1016/0005-2728(85)90122-7},
journal = {BBA - Bioenergetics},
pages = {189--201},
title = {Orientation of EPR signals arising from components in Photosystem II membranes},
url = {},
volume = {807},
year = {1985}

RIS format (EndNote, RefMan)

AB - EPR signals arising from components in oriented multilayers of Photosystem II (PS II) membranes have been studied and the following results have been obtained. (1) The EPR signals arising from the primary semiquinone-iron complex (Q-AFe) were highly oriented, with features at g = 1.90, g = 1.82 and g = 1.66 showing maxima when the membranes were perpendicular to the magnetic field. (2) The EPR signal, arising from the reduced pheophytin acceptor interacting with Q-AFe, showed an orientation-dependent splitting, ranging from 39 G when the membranes were parallel to the magnetic field to 27 G when the membranes were perpendicular to the magnetic field. (3) The S2 multiline signal associated with the O2-evolving enzyme showed an orientation dependence. This was most marked as position shifts in the low-field wings of the spectrum. These effects indicate that the component is oriented within the membrane and has some magnetically anisotropic character. (4) The component at g {reversed tilde equals} 4, though to be due to an oxidized charge carrier close to S2, showed a slight orientation dependence in its amplitude, but a significant orientation-dependent field-position shift was present, indicating that this is a magnetically anisotropic centre with a fixed geometry in the membrane. (5) Cytochrome b-559 in its oxidized form showed large highly oriented signals. The gz 2.97 feature was maximum when the membranes were oriented parallel to the magnetic field, while the gy 2.22 was maximum when the membrane plane was perpendicular to the magnetic field. This indicates that the haem plane is perpendicular to the plane of the membrane, in agreement with previous reports using chloroplasts. Ageing of the sample brings about a change from low- to high-spin state accompanied by a change in orientation of the haem relative to the membrane (from perpendicular to approximately 45°). (6) Signal II slow, which is present in the dark and which arises from a component which acts a
AU - Rutherford,AW
DO - 10.1016/0005-2728(85)90122-7
EP - 201
PY - 1985///
SN - 0005-2728
SP - 189
TI - Orientation of EPR signals arising from components in Photosystem II membranes
T2 - BBA - Bioenergetics
UR -
VL - 807
ER -