Miscellaneous Applications of EPR to PS II

8 Miscellaneous Applications of EPR to PS II. - A number of authors used EPR to detect changes of the S-state cycle and the tyrosine radicals and correlated this with other functional aspects of the OEC and PS II. In particular, the prominent S2 state MLS and the tyrosine signals have been used for these investigations. A representative fraction of such work and some other EPR applications from the last years are discussed below. 

Styring and coworkers demonstrated the application of EPR spectroscopy of the different EPR signatures of PS II to monitor certain regions of PS II during photophosphorylation of core proteins, which is known to control repair of PS 

One of the problems to extract structural information from EPR lies in the correct simulation of the experimental spectra. Misra536 reviewed spin Hamiltonians applicable to exchange-coupled Mn complexes, and described techniques for simulation of EPR spectra. Various structural models for the Mm-cluster in PS II were presented. 

In photosynthesis radical-ions and triplet states of the pigments, radical-pairs and biradicals involving various chlorophylls and quinones, amino acid radicals, hemes in cytochromes, metal clusters of low and higher nuclearity and even coupled metallo-radical species have been observed. Thus the field of photosyn- 

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