Phosphorylation coupled to H 2 oxidation by chromatophores from Rhodopseudomonas capsulata

Abstract

The phototrophic bacterium, Rhodopseudomonas capsulata can use Hz as electron donor for either photoautotrophic or chemoautotrophic growth [ 1,2]. When grown in the presence of Ha, cells contain a relatively high hydrogenase activity of the Hz -uptake type [3]. This hydrogenase is located in the membrane [3], which also contains the redox components of the respiratory chain. Cells of Rps. capsulata grown anaerobically in the light have been shown to have respiratory activities [4] similar to those found in aerobic cells [5]. The purpose of the experiments reported here was to show that hydrogenase formed in the membranes of photosynthetically grown cells can feed electrons to the respiratory chain and that Hz oxidation is linked to ATP synthesis.