Mechanism and Macromolecular Organization in Photosynthetic Reaction Centers

点击翻译按钮获取中文摘要

Biophysical studies of the mechanism of the initial charge separation steps in photosynthetic reaction centers (RC) will be continued. The recent X-ray structure determinations of RCs from two bacterial species has focused attention on the molecular mechanism of highly efficient electron transfer in this chromophore-protein assembly. Photoinduced electron transfer generates an intermediate which is a radical pair and has a large electric dipole moment. These two characteristics make possible the manipulation of the reaction dynamics by applied magnetic and electric fields, respectively. The initial charge separation and energy storage steps in photosynthesis take place in a membrane bound chlorophyll- protein complex called the photosynthetic reaction center. The RC is the smallest isolatable unit which carries out the initial charge separation steps of photosynthesis. The three dimensional structure of the RC from two species of purple non-sulfur bacteria have been determined to atomic resolution in the past several years. Although a great deal of spectroscopic and kinetic data had been obtained before the crystal structure was solved, the availability of the atomic coordinates of all the reactive components and their solvent has stimulated great interest in understanding the underlying physics of the RC function.