LIGHT-INDUCED CHARGE SEPARATION IN PHOTOSYNTHETIC REACTION CENTERS - MAGNETIC-RESONANCE STUDIES

The radical ions formed in the charge separation process of bacterial reaction centers are studied by EPR, ENDOR, and ESEEM spectroscopy. De tails of the electronic structure are obtained via determination of th e hyperfine coupling constants. Additional information about the spati al structure is provided by the investigation of single crystals. Hydr ogen bonds between the cofactors and the protein have been detected. T hey have a profound influence on the electronic structure of the radic al ions. Specific mutants introducing or breaking hydrogen bonds to th e primary donor are described. The observed changes in the electronic structure of these mutants are correlated with changes in the electron transfer rates.