Quadrupole parameters of nitrogen nuclei in the cation radical P.+700 determined by ESEEM of single crystals of photosystem I

H. Käß, Petra Fromme, W. Lubitz

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The cation radical of the primary donor P700 of photosystem I (PS I) is investigated by ESEEM on single crystals of PS I from the cyanobacterium Synechococcus elongatus. The nuclear quadrupole parameters Κ and η of five different 14N nuclei are determined and 14N hyperfine couplings (hfc's) of P.+700 are evaluated. For comparison the cation of methyl-chlorophyllide a is studied in frozen solution. The 14N hfc data agree with published results for the 15N-labeled cation radicals of P700 and chlorophyll a and are discussed in terms of a chlorophyll a dimer model for the cation radical P.+700.

Original languageEnglish
Pages (from-to)197-206
Number of pages10
JournalChemical Physics Letters
Issue number1-2
Publication statusPublished - Jul 19 1996


ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Spectroscopy
  • Atomic and Molecular Physics, and Optics

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