TY - JOUR
T1 - Photosystem II single crystals studied by EPR spectroscopy at 94 GHz
T2 - The tyrosine radical Yd•
AU - Hofbauer, W.
AU - Zouni, A.
AU - Bittl, R.
AU - Kern, J.
AU - Orth, P.
AU - Lendzian, F.
AU - Fromme, P.
AU - Witt, H. T.
AU - Lubitz, W.
PY - 2001/6/5
Y1 - 2001/6/5
N2 - Electron paramagnetic resonance (EPR) spectroscopy at 94 GHz is used to study the dark-stable tyrosine radical YD• in single crystals of photosystem II core complexes (cc) isolated from the thermophilic cyanobacterium Synechococcus elongatus. These complexes contain at least 17 subunits, including the water-oxidizing complex (WOC), and 32 chlorophyll a molecules/PS II; they are active in light-induced electron transfer and water oxidation. The crystals belong to the orthorhombic space group P212121, with four PS II dimers per unit cell. High-frequency EPR is used for enhancing the sensitivity of experiments performed on small single crystals as well as for increasing the spectral resolution of the g tensor components and of the different crystal sites. Magnitude and orientation of the g tensor of YD• and related information on several proton hyperfine tensors are deduced from analysis of angular-dependent EPR spectra. The precise orientation of tyrosine YD• in PS II is obtained as a first step in the EPR characterization of paramagnetic species in these single crystals.
AB - Electron paramagnetic resonance (EPR) spectroscopy at 94 GHz is used to study the dark-stable tyrosine radical YD• in single crystals of photosystem II core complexes (cc) isolated from the thermophilic cyanobacterium Synechococcus elongatus. These complexes contain at least 17 subunits, including the water-oxidizing complex (WOC), and 32 chlorophyll a molecules/PS II; they are active in light-induced electron transfer and water oxidation. The crystals belong to the orthorhombic space group P212121, with four PS II dimers per unit cell. High-frequency EPR is used for enhancing the sensitivity of experiments performed on small single crystals as well as for increasing the spectral resolution of the g tensor components and of the different crystal sites. Magnitude and orientation of the g tensor of YD• and related information on several proton hyperfine tensors are deduced from analysis of angular-dependent EPR spectra. The precise orientation of tyrosine YD• in PS II is obtained as a first step in the EPR characterization of paramagnetic species in these single crystals.
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U2 - 10.1073/pnas.101127598
DO - 10.1073/pnas.101127598
M3 - Article
C2 - 11381107
AN - SCOPUS:0035810932
SN - 0027-8424
VL - 98
SP - 6623
EP - 6628
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 12
ER -