In Vivo Control of Glutamine Synthetase in the Facultative Phototrophic Bacterium Rhodopseudomonas sphaeroides

Abstract

In vivo control of glutamine synthetase (GS) in the facultative phototrophic bacterium Rhodopseudomonas sphaeroides was studied. The enzyme was partially purified from cells grown photosynthetically in ammonium-malate-medium. Its catalytic properties were characteristically changed by incubation with phosphodiesterase indicating an in vivo regulation by adenylylation/deadenylylation. Adenylylation states of GS were measured as a function of variations in the nitrogen source and the light intensity during photosynthetic growth.