The aim of Dr. Feher's research program is to contribute toward an understanding of the primary processes in photosynthesis, i.e., the mechanism of conversion of electromagnetic energy into chemical free energy. He is focusing his studies on the photosynthetic process in purple bacteria (e.g. Rhodopseudomonas sphaeriodes). The work is divided into two main categories: 1) Structural aspects of the reaction center: In parallel with the determination of the spatial (three dimensional) structure of the bacteriochlorophyll-protein complex called the reaction center (RC), the electronic structure of the primary reactants (donors and acceptors) is being determined by a variety of techniques, including electron paramagnetic resonance, electron nuclear double resonance and optical spectroscopy. The effects of structural modifications of the RC (e. g. by site directed mutagenesis, removal of iron etc.) on the function are being investigated. 2) Functional aspects of the reaction center: Electron transfer in RCs is being investigated by measuring the effect of electric fields on the kinetics as well as the effect of isotopic substitution (deuteration). Protonation of both the one and two electron states is being studied using site directed mutagenesis.
