TY - JOUR
T1 - g-anisotropy of the S2-state manganese cluster in single crystals of cyanobacterial photosystem II studied by W-band electron paramagnetic resonance spectroscopy
AU - Matsuoka, Hideto
AU - Furukawa, Ko
AU - Kato, Tatsuhi
AU - Mino, Hiroyuki
AU - Shen, Jian Ren
AU - Kawamori, Asako
PY - 2006/7/6
Y1 - 2006/7/6
N2 - The multiline signal from the S2-state manganese cluster in the oxygen evolving complex of photosystem II (PSII) was observed in single, crystals of a thermophilic cyanobacterium Thermosynechococcus vulcanus for the first time by W-band (94 GHz) electron paramagnetic resonance (EPR). At W-band, spectra were characterized by the g-anisotropy, which enabled the precise determination of the tensor. Distinct hyperfine splittings (hfs's) as seen in frozen solutions of PSII at X-band (9.5 GHz) were detected in most of the crystal orientations relative to the magnetic field. In some orientations, however, the hfs's disappeared due to overlapping of a large number of EPR lines from eight crystallographic symmetry-related sites of the manganese cluster within the unit cell of the crystal. Analysis of the orientation-dependent spectral features yielded the following g-tensor components: gx = 1.988, gz = 1.981, gz = 1.965. The principal values suggested an approximate axial symmetry around the Mn(III) ion in the cluster.
AB - The multiline signal from the S2-state manganese cluster in the oxygen evolving complex of photosystem II (PSII) was observed in single, crystals of a thermophilic cyanobacterium Thermosynechococcus vulcanus for the first time by W-band (94 GHz) electron paramagnetic resonance (EPR). At W-band, spectra were characterized by the g-anisotropy, which enabled the precise determination of the tensor. Distinct hyperfine splittings (hfs's) as seen in frozen solutions of PSII at X-band (9.5 GHz) were detected in most of the crystal orientations relative to the magnetic field. In some orientations, however, the hfs's disappeared due to overlapping of a large number of EPR lines from eight crystallographic symmetry-related sites of the manganese cluster within the unit cell of the crystal. Analysis of the orientation-dependent spectral features yielded the following g-tensor components: gx = 1.988, gz = 1.981, gz = 1.965. The principal values suggested an approximate axial symmetry around the Mn(III) ion in the cluster.
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U2 - 10.1021/jp055008f
DO - 10.1021/jp055008f
M3 - Article
C2 - 16805638
AN - SCOPUS:33746328682
VL - 110
SP - 13242
EP - 13247
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 26
ER -