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High‐field (94‐GHz) EPR spectroscopy on the S 2 multiline signal of photosystem II
Author(s) -
Teutloff Christian,
Keßen Sven,
Kern Jan,
Zouni Athina,
Bittl Robert
Publication year - 2006
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2006.05.039
Subject(s) - hyperfine structure , photosystem ii , electron paramagnetic resonance , chemistry , manganese , spectroscopy , spectral line , analytical chemistry (journal) , crystal (programming language) , molecular physics , nuclear magnetic resonance , atomic physics , physics , photosynthesis , biochemistry , organic chemistry , quantum mechanics , astronomy , chromatography , computer science , programming language
The multiline signal of the S 2 state in Photosystem II was measured both in frozen‐solution and single‐crystal preparations from the cyanobacterium Thermosynechococcus elongatus . The frozen‐solution EPR spectrum shows a gaussian‐like line shape without any resolution of Mn hyperfine couplings. This line shape can be understood on the basis of the single‐crystal spectra, where a strong orientation dependence of partially resolved hyperfine structures appears. Simulation of the frozen‐solution spectrum on the basis of Mn hyperfine couplings taken from published pulse‐ENDOR data yields a fully rhombic g ‐matrix for the multiline signal with principal components 1.997, 1.970, and 1.965. The resulting isotropic g ‐value g iso = 1.977 is surprisingly small compared to other manganese complexes containing manganese ions in the formal oxidation states three and four.