EVALUATION OF 2D-ESEEM DATA OF N-15-LABELED RADICAL CATIONS OF THE PRIMARY DONOR P-700 IN PHOTOSYSTEM-I AND CHLOROPHYLL-A

Hyperfine couplings (hfc's) of the nitrogen nuclei in the N-15-labeled radical cations of chlorophyll a and the primary donor P-700 in photo system I of spinach were investigated in frozen solution by two-dimens ional stimulated echo ESEEM. N-15 hfc tensors were evaluated by compar ison of the experimental data with simulations of the time domain and frequency domain ESEEM signals. The results are discussed in the frame work of a chlorophyll a dimer model for the radical cation of P-700.