COUPLING AND CONTROL AT THE CYTOCHROME LEVEL OF BACTERIAL PHOTOSYNTHETIC ELECTRON TRANSPORT

Abstract

This chapter focuses on coupling and control at the cytochrome level of bacterial photosynthetic electron transport. In the light-induced cyclic electron transport system of chromatophores from the photosynthetic bacterium Rhodospirillum rubrum reversible changes occur in the steady-state oxidation reduction level of cytochromes upon addition of low concentrations of ADP. Both in bacterial and in plant light-induced electron transport the first and so far the only coupling site that has been localized is at the cytochrome level linked to the oxidation of b-type cytochrome. Rhodospirillum rubrum, strain S-1 or G-9 were grown and chromatophores prepared. Uncoupling agents, such as FCCP, will effectively inhibit the ADP cycles and when added under illumination cause a rapid oxidation of the b-type cytochrome in chromatophores.