Magnetic structure of manganese cluster in photosystem II investigated by electron paramagnetic resonance
نویسندگان
چکیده
The electronic structure of manganese (Mn) cluster in photosystem II was investigated by electron paramagnetic resonance (EPR) spectroscopy. In order to determine the spin density distribution in magnetically coupled Mn in the S2 state Mn cluster, pulsed electron-electron double resonance (PELDOR) measurement was performed. The local environment of the Mn cluster was investigated by electron-nuclear double resonance (ENDOR). Using spin projections determined by PELDOR, ENDOR signals were assigned to the water molecules ligated to the Mn cluster. The location of a high-affinity Mn2+ site in apo-photosystem II, which is the initial site of photoactivation of the Mn cluster, was determined by PELDOR.
منابع مشابه
Proximity of the manganese cluster of photosystem II to the redox-active tyrosine YZ.
Electron spin echo electron-nuclear double resonance (ESE-ENDOR) experiments performed on a broad radical electron paramagnetic resonance (EPR) signal observed in photosystem II particles depleted of Ca2+ indicate that this signal arises from the redox-active tyrosine YZ. The tyrosine EPR signal width is increased relative to that observed in a manganese-depleted preparation due to a magnetic i...
متن کاملRecent pulsed EPR studies of the photosystem II oxygen-evolving complex: implications as to water oxidation mechanisms.
The pulsed electron paramagnetic resonance (EPR) methods of electron spin echo envelope modulation (ESEEM) and electron spin echo-electron nuclear double resonance (ESE-ENDOR) are used to investigate the structure of the Photosystem II oxygen-evolving complex (OEC), including the paramagnetic manganese cluster and its immediate surroundings. Recent unpublished results from the pulsed EPR labora...
متن کاملComparative studies of the S0 and S2 multiline electron paramagnetic resonance signals from the manganese cluster in Photosystem II.
Electron paramagnetic resonance (EPR) spectroscopy is one of the major techniques used to analyse the structure and function of the water oxidising complex (WOC) in Photosystem II. The discovery of an EPR signal from the S0 state has opened the way for new experiments, aiming to characterise the S0 state and elucidate the differences between the different S states. We present a review of the bi...
متن کاملMultifrequency pulsed electron paramagnetic resonance study of the S2 state of the photosystem II manganese cluster.
Multifrequency electron spin-echo envelope modulation (ESEEM) spectroscopy is employed to measure the strength of the hyperfine coupling of magnetic nuclei to the paramagnetic (S = 1/2) S2 form of photosystem II (PSII). Previous X-band-frequency ESEEM studies indicated that one or more histidine nitrogens are electronically coupled to the tetranuclear manganese cluster in the S2 state of PSII. ...
متن کاملDetection of an electron paramagnetic resonance signal in the S0 state of the manganese complex of photosystem II from Synechococcus elongatus.
The Mn(4)-cluster of photosystem II (PSII) from Synechococcus elongatus was studied by electron paramagnetic resonance (EPR) spectroscopy after a series of saturating laser flashes given in the presence of either methanol or ethanol. Results were compared to those obtained in similar experiments done on PSII isolated from plants. The flash-dependent changes in amplitude of the EPR multiline sig...
متن کامل