Pressure Effects on Electron Transfer in Bacterial Reaction Centers

Abstract

Studies of the effects of pressure on the various electron transfer reactions, both forward and backward, that mediate charge separation and recombination in bacterial reaction centers, can provide useful information on changes in conformation and distances involving the various chromophores and their protein scaffolding that may accompany these movements of charge. We have recently reported the effects of pressure on the rates of one forward reaction and three back reactions for two species of photosynthetic bacteria, Rb. sphaeroides and Rps. viridis (1). In this brief report I review these results and compare them with earlier studies of the temperature dependence of these processes (2,3). A simple model is proposed that appears to account for both pressure and temperature data and which can be tested by additional experiments.